Hi all,
Is there a way to have the LPC11C2x wakeup from a low-power mode when there is
any activity on the CANbus?
Looking at the datasheets I cannot see a way to generate an interrupt or wake-up
event from the CAN RX signal, which has no physical pin on this part. The RX
signal is available in the CANTEST register, but no interrupt seems to monitor
this bit.
Without this ability, it seems the entire C_CAN controller must remaining
running in order to detect traffic on the CANbus. This puts a pretty large lower
limit on the power consumption... :-(
Anyone have any ideas?
Thanks,
Kevin.
LPC11C2x wakeup on CAN activity?
Started by ●November 7, 2012
Reply by ●November 7, 20122012-11-07
Hi Kevin,
Although we are not using the LPC11C2x (we use the LPC1765), you might
use the CAN driver TJA1041 for a wake up. The TJA1041 can be put into
sleep mode, but as soon as CAN activity is detected then the INH
pin will be going from "closed" to "open" (INH is an internal FET).
The output of the INH pin with a possible level converter in between
can be routed to an interrupt capable pin.
I have not look thoroughly well on the TI site, but they have similar
CAN drivers with less pins.
Hopes this helps.
Br,
Armand
On 11/07/2012 06:07 AM, Kevin wrote:
> Hi all,
>
> Is there a way to have the LPC11C2x wakeup from a low-power mode when there is any activity on the CANbus?
>
> Looking at the datasheets I cannot see a way to generate an interrupt or wake-up event from the CAN RX signal, which has no physical pin on this part. The RX signal is available in the CANTEST register, but no interrupt seems to monitor this bit.
>
> Without this ability, it seems the entire C_CAN controller must remaining running in order to detect traffic on the CANbus. This puts a pretty large lower limit on the power consumption... :-(
>
> Anyone have any ideas?
>
> Thanks,
> Kevin.
>
Although we are not using the LPC11C2x (we use the LPC1765), you might
use the CAN driver TJA1041 for a wake up. The TJA1041 can be put into
sleep mode, but as soon as CAN activity is detected then the INH
pin will be going from "closed" to "open" (INH is an internal FET).
The output of the INH pin with a possible level converter in between
can be routed to an interrupt capable pin.
I have not look thoroughly well on the TI site, but they have similar
CAN drivers with less pins.
Hopes this helps.
Br,
Armand
On 11/07/2012 06:07 AM, Kevin wrote:
> Hi all,
>
> Is there a way to have the LPC11C2x wakeup from a low-power mode when there is any activity on the CANbus?
>
> Looking at the datasheets I cannot see a way to generate an interrupt or wake-up event from the CAN RX signal, which has no physical pin on this part. The RX signal is available in the CANTEST register, but no interrupt seems to monitor this bit.
>
> Without this ability, it seems the entire C_CAN controller must remaining running in order to detect traffic on the CANbus. This puts a pretty large lower limit on the power consumption... :-(
>
> Anyone have any ideas?
>
> Thanks,
> Kevin.
>
Reply by ●November 7, 20122012-11-07
Hi Armand,
Thanks for your reply, but the "nice" thing about the LPC11C2x part is that is has an inbuilt CAN transceiver. So using an external transceiver invalidates the purpose of using the LPC11C2x in the first place.
Seems a bit of an oversight by NXP that they didn't allow better interrupt/wakeup functionality when they integrated the CAN :-(
Regards,
Kevin.
--- In l..., Armand wrote:
>
> Hi Kevin,
>
> Although we are not using the LPC11C2x (we use the LPC1765), you might
> use the CAN driver TJA1041 for a wake up. The TJA1041 can be put into
> sleep mode, but as soon as CAN activity is detected then the INH
> pin will be going from "closed" to "open" (INH is an internal FET).
> The output of the INH pin with a possible level converter in between
> can be routed to an interrupt capable pin.
>
> I have not look thoroughly well on the TI site, but they have similar
> CAN drivers with less pins.
>
> Hopes this helps.
>
> Br,
>
> Armand
> On 11/07/2012 06:07 AM, Kevin wrote:
> > Hi all,
> >
> > Is there a way to have the LPC11C2x wakeup from a low-power mode when there is any activity on the CANbus?
> >
> > Looking at the datasheets I cannot see a way to generate an interrupt or wake-up event from the CAN RX signal, which has no physical pin on this part. The RX signal is available in the CANTEST register, but no interrupt seems to monitor this bit.
> >
> > Without this ability, it seems the entire C_CAN controller must remaining running in order to detect traffic on the CANbus. This puts a pretty large lower limit on the power consumption... :-(
> >
> > Anyone have any ideas?
> >
> > Thanks,
> > Kevin.
> >
> >
>
Thanks for your reply, but the "nice" thing about the LPC11C2x part is that is has an inbuilt CAN transceiver. So using an external transceiver invalidates the purpose of using the LPC11C2x in the first place.
Seems a bit of an oversight by NXP that they didn't allow better interrupt/wakeup functionality when they integrated the CAN :-(
Regards,
Kevin.
--- In l..., Armand wrote:
>
> Hi Kevin,
>
> Although we are not using the LPC11C2x (we use the LPC1765), you might
> use the CAN driver TJA1041 for a wake up. The TJA1041 can be put into
> sleep mode, but as soon as CAN activity is detected then the INH
> pin will be going from "closed" to "open" (INH is an internal FET).
> The output of the INH pin with a possible level converter in between
> can be routed to an interrupt capable pin.
>
> I have not look thoroughly well on the TI site, but they have similar
> CAN drivers with less pins.
>
> Hopes this helps.
>
> Br,
>
> Armand
> On 11/07/2012 06:07 AM, Kevin wrote:
> > Hi all,
> >
> > Is there a way to have the LPC11C2x wakeup from a low-power mode when there is any activity on the CANbus?
> >
> > Looking at the datasheets I cannot see a way to generate an interrupt or wake-up event from the CAN RX signal, which has no physical pin on this part. The RX signal is available in the CANTEST register, but no interrupt seems to monitor this bit.
> >
> > Without this ability, it seems the entire C_CAN controller must remaining running in order to detect traffic on the CANbus. This puts a pretty large lower limit on the power consumption... :-(
> >
> > Anyone have any ideas?
> >
> > Thanks,
> > Kevin.
> >
> >
>
Reply by ●November 9, 20122012-11-09
Il 08/11/2012 02:40, Kevin ha scritto:
>
>
> Hi Armand,
>
> Thanks for your reply, but the "nice" thing about the LPC11C2x part is
> that is has an inbuilt CAN transceiver. So using an external
> transceiver invalidates the purpose of using the LPC11C2x in the first
> place.
>
> Seems a bit of an oversight by NXP that they didn't allow better
> interrupt/wakeup functionality when they integrated the CAN :-(
>
In practice CAN is most used in automotive and industrial applications
where the sleep mode offered by LPC11Cxx is perfectly adequate and the
other most deeper sleep modes aren't very adequate because it is better
to have the microcontroller really off.
Remember that in automotive and industrial application the power
consumption due to the microcontroller is a little fraction compared
with the rest of the board consumption.
For other application I2C is a good candidate for multi processor
communication bus both for inter board and board to board communications
and you could also use it for "extreme" long distance communications
with some care. Personally I achieved better long distance results with
I2C then CAN bus so it is only design matter.
> Regards,
> Kevin.
>
> --- In l... ,
> Armand wrote:
> >
> > Hi Kevin,
> >
> > Although we are not using the LPC11C2x (we use the LPC1765), you might
> > use the CAN driver TJA1041 for a wake up. The TJA1041 can be put into
> > sleep mode, but as soon as CAN activity is detected then the INH
> > pin will be going from "closed" to "open" (INH is an internal FET).
> > The output of the INH pin with a possible level converter in between
> > can be routed to an interrupt capable pin.
> >
> > I have not look thoroughly well on the TI site, but they have similar
> > CAN drivers with less pins.
> >
> > Hopes this helps.
> >
> > Br,
> >
> > Armand
> >
> >
> > On 11/07/2012 06:07 AM, Kevin wrote:
> > > Hi all,
> > >
> > > Is there a way to have the LPC11C2x wakeup from a low-power mode
> when there is any activity on the CANbus?
> > >
> > > Looking at the datasheets I cannot see a way to generate an
> interrupt or wake-up event from the CAN RX signal, which has no
> physical pin on this part. The RX signal is available in the CANTEST
> register, but no interrupt seems to monitor this bit.
> > >
> > > Without this ability, it seems the entire C_CAN controller must
> remaining running in order to detect traffic on the CANbus. This puts
> a pretty large lower limit on the power consumption... :-(
> > >
> > > Anyone have any ideas?
> > >
> > > Thanks,
> > > Kevin.
> > >
> > >
> > >
> >
>
>
> Hi Armand,
>
> Thanks for your reply, but the "nice" thing about the LPC11C2x part is
> that is has an inbuilt CAN transceiver. So using an external
> transceiver invalidates the purpose of using the LPC11C2x in the first
> place.
>
> Seems a bit of an oversight by NXP that they didn't allow better
> interrupt/wakeup functionality when they integrated the CAN :-(
>
In practice CAN is most used in automotive and industrial applications
where the sleep mode offered by LPC11Cxx is perfectly adequate and the
other most deeper sleep modes aren't very adequate because it is better
to have the microcontroller really off.
Remember that in automotive and industrial application the power
consumption due to the microcontroller is a little fraction compared
with the rest of the board consumption.
For other application I2C is a good candidate for multi processor
communication bus both for inter board and board to board communications
and you could also use it for "extreme" long distance communications
with some care. Personally I achieved better long distance results with
I2C then CAN bus so it is only design matter.
> Regards,
> Kevin.
>
> --- In l... ,
> Armand wrote:
> >
> > Hi Kevin,
> >
> > Although we are not using the LPC11C2x (we use the LPC1765), you might
> > use the CAN driver TJA1041 for a wake up. The TJA1041 can be put into
> > sleep mode, but as soon as CAN activity is detected then the INH
> > pin will be going from "closed" to "open" (INH is an internal FET).
> > The output of the INH pin with a possible level converter in between
> > can be routed to an interrupt capable pin.
> >
> > I have not look thoroughly well on the TI site, but they have similar
> > CAN drivers with less pins.
> >
> > Hopes this helps.
> >
> > Br,
> >
> > Armand
> >
> >
> > On 11/07/2012 06:07 AM, Kevin wrote:
> > > Hi all,
> > >
> > > Is there a way to have the LPC11C2x wakeup from a low-power mode
> when there is any activity on the CANbus?
> > >
> > > Looking at the datasheets I cannot see a way to generate an
> interrupt or wake-up event from the CAN RX signal, which has no
> physical pin on this part. The RX signal is available in the CANTEST
> register, but no interrupt seems to monitor this bit.
> > >
> > > Without this ability, it seems the entire C_CAN controller must
> remaining running in order to detect traffic on the CANbus. This puts
> a pretty large lower limit on the power consumption... :-(
> > >
> > > Anyone have any ideas?
> > >
> > > Thanks,
> > > Kevin.
> > >
> > >
> > >
> >
Reply by ●November 10, 20122012-11-10
Hi,
This can be achieved. It depends on which low power mode you are referring to.
In Sleep Mode (referred to in section 3.9.2 of the user manual): The C_CAN module can wake up the chip. since the C_CAN is a Vectored interrupt as pointed to in section 6.4.
In deep sleep mode (referred to in section 3.9.3 of the user manual): This can be achieved with a small work around. You can tie the CAN_TxD/CAN_RxD to any one of the pins PIO0_0 to PIO0_11 and PIO1_0 and then wake up the LPC11Cxx from Deep-sleep mode.
In deep power down mode (referred to in section 3.9.3 of the user manual): A similar work around like the one pointed to earlier can be done but the signal needs to be tied to the wakeup pin instead (A more detailed description of the procedure to wake up the chip from deep-power down is given in section 2.9.4.3 of the user manual).
--- In l..., "Kevin" wrote:
>
> Hi all,
>
> Is there a way to have the LPC11C2x wakeup from a low-power mode when there is any activity on the CANbus?
>
> Looking at the datasheets I cannot see a way to generate an interrupt or wake-up event from the CAN RX signal, which has no physical pin on this part. The RX signal is available in the CANTEST register, but no interrupt seems to monitor this bit.
>
> Without this ability, it seems the entire C_CAN controller must remaining running in order to detect traffic on the CANbus. This puts a pretty large lower limit on the power consumption... :-(
>
> Anyone have any ideas?
>
> Thanks,
> Kevin.
>
This can be achieved. It depends on which low power mode you are referring to.
In Sleep Mode (referred to in section 3.9.2 of the user manual): The C_CAN module can wake up the chip. since the C_CAN is a Vectored interrupt as pointed to in section 6.4.
In deep sleep mode (referred to in section 3.9.3 of the user manual): This can be achieved with a small work around. You can tie the CAN_TxD/CAN_RxD to any one of the pins PIO0_0 to PIO0_11 and PIO1_0 and then wake up the LPC11Cxx from Deep-sleep mode.
In deep power down mode (referred to in section 3.9.3 of the user manual): A similar work around like the one pointed to earlier can be done but the signal needs to be tied to the wakeup pin instead (A more detailed description of the procedure to wake up the chip from deep-power down is given in section 2.9.4.3 of the user manual).
--- In l..., "Kevin" wrote:
>
> Hi all,
>
> Is there a way to have the LPC11C2x wakeup from a low-power mode when there is any activity on the CANbus?
>
> Looking at the datasheets I cannot see a way to generate an interrupt or wake-up event from the CAN RX signal, which has no physical pin on this part. The RX signal is available in the CANTEST register, but no interrupt seems to monitor this bit.
>
> Without this ability, it seems the entire C_CAN controller must remaining running in order to detect traffic on the CANbus. This puts a pretty large lower limit on the power consumption... :-(
>
> Anyone have any ideas?
>
> Thanks,
> Kevin.
>
Reply by ●November 10, 20122012-11-10
--- In l..., "M. Manca" wrote:
Hi,
This is possible. The procedure depends on the mode you are in.
In Sleep mode (AS pointed to in Section 3.9.2 of the user manual): The chip will wake up if any of the Vectored interrupts (explained in chapter) are asserted. The C_CAN interrupt is a Vectored interrupt.
In Deep Sleep mode (AS pointed to in Section 3.9.3 of the user manual): You can tie the CAN_RxD to any one of the pins PIO0_0 to PIO0_11 and PIO1_0 and then wake up the LPC11Cxx from Deep-sleep mode. Section 3.9.3.3 explains the procedure in more detail.
In Deep power down mode: You can tie the WAKEUP pin to the CAN_RxD and wakeup the chip. A detailed description of the procedure to be followed is described in the section 3.9.4.3.
>
> Il 08/11/2012 02:40, Kevin ha scritto:
> >
> >
> > Hi Armand,
> >
> > Thanks for your reply, but the "nice" thing about the LPC11C2x part is
> > that is has an inbuilt CAN transceiver. So using an external
> > transceiver invalidates the purpose of using the LPC11C2x in the first
> > place.
> >
> > Seems a bit of an oversight by NXP that they didn't allow better
> > interrupt/wakeup functionality when they integrated the CAN :-(
> >
> In practice CAN is most used in automotive and industrial applications
> where the sleep mode offered by LPC11Cxx is perfectly adequate and the
> other most deeper sleep modes aren't very adequate because it is better
> to have the microcontroller really off.
>
> Remember that in automotive and industrial application the power
> consumption due to the microcontroller is a little fraction compared
> with the rest of the board consumption.
>
> For other application I2C is a good candidate for multi processor
> communication bus both for inter board and board to board communications
> and you could also use it for "extreme" long distance communications
> with some care. Personally I achieved better long distance results with
> I2C then CAN bus so it is only design matter.
> >
> >
> > Regards,
> > Kevin.
> >
> > --- In l... ,
> > Armand wrote:
> > >
> > > Hi Kevin,
> > >
> > > Although we are not using the LPC11C2x (we use the LPC1765), you might
> > > use the CAN driver TJA1041 for a wake up. The TJA1041 can be put into
> > > sleep mode, but as soon as CAN activity is detected then the INH
> > > pin will be going from "closed" to "open" (INH is an internal FET).
> > > The output of the INH pin with a possible level converter in between
> > > can be routed to an interrupt capable pin.
> > >
> > > I have not look thoroughly well on the TI site, but they have similar
> > > CAN drivers with less pins.
> > >
> > > Hopes this helps.
> > >
> > > Br,
> > >
> > > Armand
> > >
> > >
> > > On 11/07/2012 06:07 AM, Kevin wrote:
> > > > Hi all,
> > > >
> > > > Is there a way to have the LPC11C2x wakeup from a low-power mode
> > when there is any activity on the CANbus?
> > > >
> > > > Looking at the datasheets I cannot see a way to generate an
> > interrupt or wake-up event from the CAN RX signal, which has no
> > physical pin on this part. The RX signal is available in the CANTEST
> > register, but no interrupt seems to monitor this bit.
> > > >
> > > > Without this ability, it seems the entire C_CAN controller must
> > remaining running in order to detect traffic on the CANbus. This puts
> > a pretty large lower limit on the power consumption... :-(
> > > >
> > > > Anyone have any ideas?
> > > >
> > > > Thanks,
> > > > Kevin.
> > > >
> > > >
> > > >
> > >
> >
> >
>
Hi,
This is possible. The procedure depends on the mode you are in.
In Sleep mode (AS pointed to in Section 3.9.2 of the user manual): The chip will wake up if any of the Vectored interrupts (explained in chapter) are asserted. The C_CAN interrupt is a Vectored interrupt.
In Deep Sleep mode (AS pointed to in Section 3.9.3 of the user manual): You can tie the CAN_RxD to any one of the pins PIO0_0 to PIO0_11 and PIO1_0 and then wake up the LPC11Cxx from Deep-sleep mode. Section 3.9.3.3 explains the procedure in more detail.
In Deep power down mode: You can tie the WAKEUP pin to the CAN_RxD and wakeup the chip. A detailed description of the procedure to be followed is described in the section 3.9.4.3.
>
> Il 08/11/2012 02:40, Kevin ha scritto:
> >
> >
> > Hi Armand,
> >
> > Thanks for your reply, but the "nice" thing about the LPC11C2x part is
> > that is has an inbuilt CAN transceiver. So using an external
> > transceiver invalidates the purpose of using the LPC11C2x in the first
> > place.
> >
> > Seems a bit of an oversight by NXP that they didn't allow better
> > interrupt/wakeup functionality when they integrated the CAN :-(
> >
> In practice CAN is most used in automotive and industrial applications
> where the sleep mode offered by LPC11Cxx is perfectly adequate and the
> other most deeper sleep modes aren't very adequate because it is better
> to have the microcontroller really off.
>
> Remember that in automotive and industrial application the power
> consumption due to the microcontroller is a little fraction compared
> with the rest of the board consumption.
>
> For other application I2C is a good candidate for multi processor
> communication bus both for inter board and board to board communications
> and you could also use it for "extreme" long distance communications
> with some care. Personally I achieved better long distance results with
> I2C then CAN bus so it is only design matter.
> >
> >
> > Regards,
> > Kevin.
> >
> > --- In l... ,
> > Armand wrote:
> > >
> > > Hi Kevin,
> > >
> > > Although we are not using the LPC11C2x (we use the LPC1765), you might
> > > use the CAN driver TJA1041 for a wake up. The TJA1041 can be put into
> > > sleep mode, but as soon as CAN activity is detected then the INH
> > > pin will be going from "closed" to "open" (INH is an internal FET).
> > > The output of the INH pin with a possible level converter in between
> > > can be routed to an interrupt capable pin.
> > >
> > > I have not look thoroughly well on the TI site, but they have similar
> > > CAN drivers with less pins.
> > >
> > > Hopes this helps.
> > >
> > > Br,
> > >
> > > Armand
> > >
> > >
> > > On 11/07/2012 06:07 AM, Kevin wrote:
> > > > Hi all,
> > > >
> > > > Is there a way to have the LPC11C2x wakeup from a low-power mode
> > when there is any activity on the CANbus?
> > > >
> > > > Looking at the datasheets I cannot see a way to generate an
> > interrupt or wake-up event from the CAN RX signal, which has no
> > physical pin on this part. The RX signal is available in the CANTEST
> > register, but no interrupt seems to monitor this bit.
> > > >
> > > > Without this ability, it seems the entire C_CAN controller must
> > remaining running in order to detect traffic on the CANbus. This puts
> > a pretty large lower limit on the power consumption... :-(
> > > >
> > > > Anyone have any ideas?
> > > >
> > > > Thanks,
> > > > Kevin.
> > > >
> > > >
> > > >
> > >
> >
> >
>
Reply by ●November 10, 20122012-11-10
Il 10/11/2012 04:38, praj1029 ha scritto:
>
>
> --- In l... , "M.
> Manca" wrote:
>
> Hi,
> This is possible. The procedure depends on the mode you are in.
>
> In Sleep mode (AS pointed to in Section 3.9.2 of the user manual): The
> chip will wake up if any of the Vectored interrupts (explained in
> chapter) are asserted. The C_CAN interrupt is a Vectored interrupt.
>
> In Deep Sleep mode (AS pointed to in Section 3.9.3 of the user
> manual): You can tie the CAN_RxD to any one of the pins PIO0_0 to
> PIO0_11 and PIO1_0 and then wake up the LPC11Cxx from Deep-sleep mode.
> Section 3.9.3.3 explains the procedure in more detail.
>
This should be a viable solution only if he needs to detect the traffic
on a low traffic bus because this system awake the microcontroller every
time there is a transition edge on the CAN RXD pin and not when a
specific filered message is received. To implement this feature the only
possibility offerede by this microcontroller is to put the
microcontroller in SLEEP MODE. Anyway I would like to point that
switching off the main PLL is a good practice to reduce also the static
current consumption to a bare minimum value in sleep mode.
> In Deep power down mode: You can tie the WAKEUP pin to the CAN_RxD and
> wakeup the chip. A detailed description of the procedure to be
> followed is described in the section 3.9.4.3.
>
I don't believe this could be a real good solution because the wakeup
pin accept impulses longer then 55ns then the cpu will go to reset and
only the boot time is 55microseconds and you should add initial
stabilization time (it is not a fixed period) and application
initialization.
> >
> > Il 08/11/2012 02:40, Kevin ha scritto:
> > >
> > >
> > > Hi Armand,
> > >
> > > Thanks for your reply, but the "nice" thing about the LPC11C2x part is
> > > that is has an inbuilt CAN transceiver. So using an external
> > > transceiver invalidates the purpose of using the LPC11C2x in the first
> > > place.
> > >
> > > Seems a bit of an oversight by NXP that they didn't allow better
> > > interrupt/wakeup functionality when they integrated the CAN :-(
> > >
> > In practice CAN is most used in automotive and industrial applications
> > where the sleep mode offered by LPC11Cxx is perfectly adequate and the
> > other most deeper sleep modes aren't very adequate because it is better
> > to have the microcontroller really off.
> >
> > Remember that in automotive and industrial application the power
> > consumption due to the microcontroller is a little fraction compared
> > with the rest of the board consumption.
> >
> > For other application I2C is a good candidate for multi processor
> > communication bus both for inter board and board to board communications
> > and you could also use it for "extreme" long distance communications
> > with some care. Personally I achieved better long distance results with
> > I2C then CAN bus so it is only design matter.
> > >
> > >
> > > Regards,
> > > Kevin.
> > >
> > > --- In l...
> ,
> > > Armand wrote:
> > > >
> > > > Hi Kevin,
> > > >
> > > > Although we are not using the LPC11C2x (we use the LPC1765), you
> might
> > > > use the CAN driver TJA1041 for a wake up. The TJA1041 can be put
> into
> > > > sleep mode, but as soon as CAN activity is detected then the INH
> > > > pin will be going from "closed" to "open" (INH is an internal FET).
> > > > The output of the INH pin with a possible level converter in between
> > > > can be routed to an interrupt capable pin.
> > > >
> > > > I have not look thoroughly well on the TI site, but they have
> similar
> > > > CAN drivers with less pins.
> > > >
> > > > Hopes this helps.
> > > >
> > > > Br,
> > > >
> > > > Armand
> > > >
> > > >
> > > > On 11/07/2012 06:07 AM, Kevin wrote:
> > > > > Hi all,
> > > > >
> > > > > Is there a way to have the LPC11C2x wakeup from a low-power mode
> > > when there is any activity on the CANbus?
> > > > >
> > > > > Looking at the datasheets I cannot see a way to generate an
> > > interrupt or wake-up event from the CAN RX signal, which has no
> > > physical pin on this part. The RX signal is available in the CANTEST
> > > register, but no interrupt seems to monitor this bit.
> > > > >
> > > > > Without this ability, it seems the entire C_CAN controller must
> > > remaining running in order to detect traffic on the CANbus. This puts
> > > a pretty large lower limit on the power consumption... :-(
> > > > >
> > > > > Anyone have any ideas?
> > > > >
> > > > > Thanks,
> > > > > Kevin.
> > > > >
> > > > >
> > > > >
> > > >
> > >
> > >
> >
> >
> >
> >
> >
>
>
> --- In l... , "M.
> Manca" wrote:
>
> Hi,
> This is possible. The procedure depends on the mode you are in.
>
> In Sleep mode (AS pointed to in Section 3.9.2 of the user manual): The
> chip will wake up if any of the Vectored interrupts (explained in
> chapter) are asserted. The C_CAN interrupt is a Vectored interrupt.
>
> In Deep Sleep mode (AS pointed to in Section 3.9.3 of the user
> manual): You can tie the CAN_RxD to any one of the pins PIO0_0 to
> PIO0_11 and PIO1_0 and then wake up the LPC11Cxx from Deep-sleep mode.
> Section 3.9.3.3 explains the procedure in more detail.
>
This should be a viable solution only if he needs to detect the traffic
on a low traffic bus because this system awake the microcontroller every
time there is a transition edge on the CAN RXD pin and not when a
specific filered message is received. To implement this feature the only
possibility offerede by this microcontroller is to put the
microcontroller in SLEEP MODE. Anyway I would like to point that
switching off the main PLL is a good practice to reduce also the static
current consumption to a bare minimum value in sleep mode.
> In Deep power down mode: You can tie the WAKEUP pin to the CAN_RxD and
> wakeup the chip. A detailed description of the procedure to be
> followed is described in the section 3.9.4.3.
>
I don't believe this could be a real good solution because the wakeup
pin accept impulses longer then 55ns then the cpu will go to reset and
only the boot time is 55microseconds and you should add initial
stabilization time (it is not a fixed period) and application
initialization.
> >
> > Il 08/11/2012 02:40, Kevin ha scritto:
> > >
> > >
> > > Hi Armand,
> > >
> > > Thanks for your reply, but the "nice" thing about the LPC11C2x part is
> > > that is has an inbuilt CAN transceiver. So using an external
> > > transceiver invalidates the purpose of using the LPC11C2x in the first
> > > place.
> > >
> > > Seems a bit of an oversight by NXP that they didn't allow better
> > > interrupt/wakeup functionality when they integrated the CAN :-(
> > >
> > In practice CAN is most used in automotive and industrial applications
> > where the sleep mode offered by LPC11Cxx is perfectly adequate and the
> > other most deeper sleep modes aren't very adequate because it is better
> > to have the microcontroller really off.
> >
> > Remember that in automotive and industrial application the power
> > consumption due to the microcontroller is a little fraction compared
> > with the rest of the board consumption.
> >
> > For other application I2C is a good candidate for multi processor
> > communication bus both for inter board and board to board communications
> > and you could also use it for "extreme" long distance communications
> > with some care. Personally I achieved better long distance results with
> > I2C then CAN bus so it is only design matter.
> > >
> > >
> > > Regards,
> > > Kevin.
> > >
> > > --- In l...
> ,
> > > Armand wrote:
> > > >
> > > > Hi Kevin,
> > > >
> > > > Although we are not using the LPC11C2x (we use the LPC1765), you
> might
> > > > use the CAN driver TJA1041 for a wake up. The TJA1041 can be put
> into
> > > > sleep mode, but as soon as CAN activity is detected then the INH
> > > > pin will be going from "closed" to "open" (INH is an internal FET).
> > > > The output of the INH pin with a possible level converter in between
> > > > can be routed to an interrupt capable pin.
> > > >
> > > > I have not look thoroughly well on the TI site, but they have
> similar
> > > > CAN drivers with less pins.
> > > >
> > > > Hopes this helps.
> > > >
> > > > Br,
> > > >
> > > > Armand
> > > >
> > > >
> > > > On 11/07/2012 06:07 AM, Kevin wrote:
> > > > > Hi all,
> > > > >
> > > > > Is there a way to have the LPC11C2x wakeup from a low-power mode
> > > when there is any activity on the CANbus?
> > > > >
> > > > > Looking at the datasheets I cannot see a way to generate an
> > > interrupt or wake-up event from the CAN RX signal, which has no
> > > physical pin on this part. The RX signal is available in the CANTEST
> > > register, but no interrupt seems to monitor this bit.
> > > > >
> > > > > Without this ability, it seems the entire C_CAN controller must
> > > remaining running in order to detect traffic on the CANbus. This puts
> > > a pretty large lower limit on the power consumption... :-(
> > > > >
> > > > > Anyone have any ideas?
> > > > >
> > > > > Thanks,
> > > > > Kevin.
> > > > >
> > > > >
> > > > >
> > > >
> > >
> > >
> >
> >
> >
> >
> >
Reply by ●November 11, 20122012-11-11
--- In l..., "M. Manca" wrote:
>
> Il 10/11/2012 04:38, praj1029 ha scritto:
> >
> >
> >
> >
> > --- In l... , "M.
> > Manca" wrote:
> >
> > Hi,
> > This is possible. The procedure depends on the mode you are in.
> >
> > In Sleep mode (AS pointed to in Section 3.9.2 of the user manual): The
> > chip will wake up if any of the Vectored interrupts (explained in
> > chapter) are asserted. The C_CAN interrupt is a Vectored interrupt.
> >
> > In Deep Sleep mode (AS pointed to in Section 3.9.3 of the user
> > manual): You can tie the CAN_RxD to any one of the pins PIO0_0 to
> > PIO0_11 and PIO1_0 and then wake up the LPC11Cxx from Deep-sleep mode.
> > Section 3.9.3.3 explains the procedure in more detail.
> >
> This should be a viable solution only if he needs to detect the traffic
> on a low traffic bus because this system awake the microcontroller every
> time there is a transition edge on the CAN RXD pin and not when a
> specific filered message is received. To implement this feature the only
> possibility offerede by this microcontroller is to put the
> microcontroller in SLEEP MODE. Anyway I would like to point that
> switching off the main PLL is a good practice to reduce also the static
> current consumption to a bare minimum value in sleep mode.
You are correct, the deep sleep mode will wake up the chip regardless of the filter settings. I was just presenting the options. Also, thank you for pointing out the drawbacks.
> >
> >
> > In Deep power down mode: You can tie the WAKEUP pin to the CAN_RxD and
> > wakeup the chip. A detailed description of the procedure to be
> > followed is described in the section 3.9.4.3.
> >
> I don't believe this could be a real good solution because the wakeup
> pin accept impulses longer then 55ns then the cpu will go to reset and
> only the boot time is 55microseconds and you should add initial
> stabilization time (it is not a fixed period) and application
> initialization.
Yes this solution would result in some complication because of the time constraints that are to be taken care of.
> >
> >
> > >
> > > Il 08/11/2012 02:40, Kevin ha scritto:
> > > >
> > > >
> > > > Hi Armand,
> > > >
> > > > Thanks for your reply, but the "nice" thing about the LPC11C2x part is
> > > > that is has an inbuilt CAN transceiver. So using an external
> > > > transceiver invalidates the purpose of using the LPC11C2x in the first
> > > > place.
> > > >
> > > > Seems a bit of an oversight by NXP that they didn't allow better
> > > > interrupt/wakeup functionality when they integrated the CAN :-(
> > > >
> > > In practice CAN is most used in automotive and industrial applications
> > > where the sleep mode offered by LPC11Cxx is perfectly adequate and the
> > > other most deeper sleep modes aren't very adequate because it is better
> > > to have the microcontroller really off.
> > >
> > > Remember that in automotive and industrial application the power
> > > consumption due to the microcontroller is a little fraction compared
> > > with the rest of the board consumption.
> > >
> > > For other application I2C is a good candidate for multi processor
> > > communication bus both for inter board and board to board communications
> > > and you could also use it for "extreme" long distance communications
> > > with some care. Personally I achieved better long distance results with
> > > I2C then CAN bus so it is only design matter.
> > > >
> > > >
> > > > Regards,
> > > > Kevin.
> > > >
> > > > --- In l...
> > ,
> > > > Armand wrote:
> > > > >
> > > > > Hi Kevin,
> > > > >
> > > > > Although we are not using the LPC11C2x (we use the LPC1765), you
> > might
> > > > > use the CAN driver TJA1041 for a wake up. The TJA1041 can be put
> > into
> > > > > sleep mode, but as soon as CAN activity is detected then the INH
> > > > > pin will be going from "closed" to "open" (INH is an internal FET).
> > > > > The output of the INH pin with a possible level converter in between
> > > > > can be routed to an interrupt capable pin.
> > > > >
> > > > > I have not look thoroughly well on the TI site, but they have
> > similar
> > > > > CAN drivers with less pins.
> > > > >
> > > > > Hopes this helps.
> > > > >
> > > > > Br,
> > > > >
> > > > > Armand
> > > > >
> > > > >
> > > > > On 11/07/2012 06:07 AM, Kevin wrote:
> > > > > > Hi all,
> > > > > >
> > > > > > Is there a way to have the LPC11C2x wakeup from a low-power mode
> > > > when there is any activity on the CANbus?
> > > > > >
> > > > > > Looking at the datasheets I cannot see a way to generate an
> > > > interrupt or wake-up event from the CAN RX signal, which has no
> > > > physical pin on this part. The RX signal is available in the CANTEST
> > > > register, but no interrupt seems to monitor this bit.
> > > > > >
> > > > > > Without this ability, it seems the entire C_CAN controller must
> > > > remaining running in order to detect traffic on the CANbus. This puts
> > > > a pretty large lower limit on the power consumption... :-(
> > > > > >
> > > > > > Anyone have any ideas?
> > > > > >
> > > > > > Thanks,
> > > > > > Kevin.
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> > >
> > >
> > >
> >
> >
>
>
> Il 10/11/2012 04:38, praj1029 ha scritto:
> >
> >
> >
> >
> > --- In l... , "M.
> > Manca" wrote:
> >
> > Hi,
> > This is possible. The procedure depends on the mode you are in.
> >
> > In Sleep mode (AS pointed to in Section 3.9.2 of the user manual): The
> > chip will wake up if any of the Vectored interrupts (explained in
> > chapter) are asserted. The C_CAN interrupt is a Vectored interrupt.
> >
> > In Deep Sleep mode (AS pointed to in Section 3.9.3 of the user
> > manual): You can tie the CAN_RxD to any one of the pins PIO0_0 to
> > PIO0_11 and PIO1_0 and then wake up the LPC11Cxx from Deep-sleep mode.
> > Section 3.9.3.3 explains the procedure in more detail.
> >
> This should be a viable solution only if he needs to detect the traffic
> on a low traffic bus because this system awake the microcontroller every
> time there is a transition edge on the CAN RXD pin and not when a
> specific filered message is received. To implement this feature the only
> possibility offerede by this microcontroller is to put the
> microcontroller in SLEEP MODE. Anyway I would like to point that
> switching off the main PLL is a good practice to reduce also the static
> current consumption to a bare minimum value in sleep mode.
You are correct, the deep sleep mode will wake up the chip regardless of the filter settings. I was just presenting the options. Also, thank you for pointing out the drawbacks.
> >
> >
> > In Deep power down mode: You can tie the WAKEUP pin to the CAN_RxD and
> > wakeup the chip. A detailed description of the procedure to be
> > followed is described in the section 3.9.4.3.
> >
> I don't believe this could be a real good solution because the wakeup
> pin accept impulses longer then 55ns then the cpu will go to reset and
> only the boot time is 55microseconds and you should add initial
> stabilization time (it is not a fixed period) and application
> initialization.
Yes this solution would result in some complication because of the time constraints that are to be taken care of.
> >
> >
> > >
> > > Il 08/11/2012 02:40, Kevin ha scritto:
> > > >
> > > >
> > > > Hi Armand,
> > > >
> > > > Thanks for your reply, but the "nice" thing about the LPC11C2x part is
> > > > that is has an inbuilt CAN transceiver. So using an external
> > > > transceiver invalidates the purpose of using the LPC11C2x in the first
> > > > place.
> > > >
> > > > Seems a bit of an oversight by NXP that they didn't allow better
> > > > interrupt/wakeup functionality when they integrated the CAN :-(
> > > >
> > > In practice CAN is most used in automotive and industrial applications
> > > where the sleep mode offered by LPC11Cxx is perfectly adequate and the
> > > other most deeper sleep modes aren't very adequate because it is better
> > > to have the microcontroller really off.
> > >
> > > Remember that in automotive and industrial application the power
> > > consumption due to the microcontroller is a little fraction compared
> > > with the rest of the board consumption.
> > >
> > > For other application I2C is a good candidate for multi processor
> > > communication bus both for inter board and board to board communications
> > > and you could also use it for "extreme" long distance communications
> > > with some care. Personally I achieved better long distance results with
> > > I2C then CAN bus so it is only design matter.
> > > >
> > > >
> > > > Regards,
> > > > Kevin.
> > > >
> > > > --- In l...
> > ,
> > > > Armand wrote:
> > > > >
> > > > > Hi Kevin,
> > > > >
> > > > > Although we are not using the LPC11C2x (we use the LPC1765), you
> > might
> > > > > use the CAN driver TJA1041 for a wake up. The TJA1041 can be put
> > into
> > > > > sleep mode, but as soon as CAN activity is detected then the INH
> > > > > pin will be going from "closed" to "open" (INH is an internal FET).
> > > > > The output of the INH pin with a possible level converter in between
> > > > > can be routed to an interrupt capable pin.
> > > > >
> > > > > I have not look thoroughly well on the TI site, but they have
> > similar
> > > > > CAN drivers with less pins.
> > > > >
> > > > > Hopes this helps.
> > > > >
> > > > > Br,
> > > > >
> > > > > Armand
> > > > >
> > > > >
> > > > > On 11/07/2012 06:07 AM, Kevin wrote:
> > > > > > Hi all,
> > > > > >
> > > > > > Is there a way to have the LPC11C2x wakeup from a low-power mode
> > > > when there is any activity on the CANbus?
> > > > > >
> > > > > > Looking at the datasheets I cannot see a way to generate an
> > > > interrupt or wake-up event from the CAN RX signal, which has no
> > > > physical pin on this part. The RX signal is available in the CANTEST
> > > > register, but no interrupt seems to monitor this bit.
> > > > > >
> > > > > > Without this ability, it seems the entire C_CAN controller must
> > > > remaining running in order to detect traffic on the CANbus. This puts
> > > > a pretty large lower limit on the power consumption... :-(
> > > > > >
> > > > > > Anyone have any ideas?
> > > > > >
> > > > > > Thanks,
> > > > > > Kevin.
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> > >
> > >
> > >
> >
> >
>
Reply by ●February 10, 20132013-02-10
Hi Praj / M.Manca,
Thanks for your replies - I got sidetracked and only just got back to
looking at this now...
Re your suggestions about generating an interrupt from the CAN_RXD
signal, this is what I was trying to do, but the problem is that there
is no CAN_RXD pin to connect to a PIO and create a wakeup event. The
LPC11C24 has an integrated transceiver and does not make the RXD signal
available. Well, except as a bit in the CANTEST register, but there
doesn't appear to be a way to generate an int from this bit.
Re power consumption in automotive environments, in my experience
standby power is a critical issue. The LPC11 is the main Iq component at
the moment (I am having trouble getting it less than about 4mA). By the
time there are several of these in a system the whole thing can be
drawing >20mA when it's supposed to be asleep, which is too much to add
to the drain on the vehicle's battery when not operating for an extended
period.
I think I placed too much value on the integrated transceiver when I
chose the '11C24, and I may have to ditch it in favour of a 2-chip
solution :-(
But thanks again for your comments. Hope this thread can help someone
else planning a low power design with the LPC11 parts.
Kevin.
--- In l..., "praj1029" wrote:
>
> --- In l..., "M. Manca" wrote:
> >
> > Il 10/11/2012 04:38, praj1029 ha scritto:
> > >
> > >
> > >
> > >
> > > --- In l... , "M.
> > > Manca" wrote:
> > >
> > > Hi,
> > > This is possible. The procedure depends on the mode you are in.
> > >
> > > In Sleep mode (AS pointed to in Section 3.9.2 of the user manual):
The
> > > chip will wake up if any of the Vectored interrupts (explained in
> > > chapter) are asserted. The C_CAN interrupt is a Vectored
interrupt.
> > >
> > > In Deep Sleep mode (AS pointed to in Section 3.9.3 of the user
> > > manual): You can tie the CAN_RxD to any one of the pins PIO0_0 to
> > > PIO0_11 and PIO1_0 and then wake up the LPC11Cxx from Deep-sleep
mode.
> > > Section 3.9.3.3 explains the procedure in more detail.
> > >
> > This should be a viable solution only if he needs to detect the
traffic
> > on a low traffic bus because this system awake the microcontroller
every
> > time there is a transition edge on the CAN RXD pin and not when a
> > specific filered message is received. To implement this feature the
only
> > possibility offerede by this microcontroller is to put the
> > microcontroller in SLEEP MODE. Anyway I would like to point that
> > switching off the main PLL is a good practice to reduce also the
static
> > current consumption to a bare minimum value in sleep mode.
>
> You are correct, the deep sleep mode will wake up the chip regardless
of the filter settings. I was just presenting the options. Also, thank
you for pointing out the drawbacks.
> > >
> > >
> > > In Deep power down mode: You can tie the WAKEUP pin to the CAN_RxD
and
> > > wakeup the chip. A detailed description of the procedure to be
> > > followed is described in the section 3.9.4.3.
> > >
> > I don't believe this could be a real good solution because the
wakeup
> > pin accept impulses longer then 55ns then the cpu will go to reset
and
> > only the boot time is 55microseconds and you should add initial
> > stabilization time (it is not a fixed period) and application
> > initialization.
>
> Yes this solution would result in some complication because of the
time constraints that are to be taken care of.
>
> > >
> > >
> > > >
> > > > Il 08/11/2012 02:40, Kevin ha scritto:
> > > > >
> > > > >
> > > > > Hi Armand,
> > > > >
> > > > > Thanks for your reply, but the "nice" thing about the LPC11C2x
part is
> > > > > that is has an inbuilt CAN transceiver. So using an external
> > > > > transceiver invalidates the purpose of using the LPC11C2x in
the first
> > > > > place.
> > > > >
> > > > > Seems a bit of an oversight by NXP that they didn't allow
better
> > > > > interrupt/wakeup functionality when they integrated the CAN
:-(
> > > > >
> > > > In practice CAN is most used in automotive and industrial
applications
> > > > where the sleep mode offered by LPC11Cxx is perfectly adequate
and the
> > > > other most deeper sleep modes aren't very adequate because it is
better
> > > > to have the microcontroller really off.
> > > >
> > > > Remember that in automotive and industrial application the power
> > > > consumption due to the microcontroller is a little fraction
compared
> > > > with the rest of the board consumption.
> > > >
> > > > For other application I2C is a good candidate for multi
processor
> > > > communication bus both for inter board and board to board
communications
> > > > and you could also use it for "extreme" long distance
communications
> > > > with some care. Personally I achieved better long distance
results with
> > > > I2C then CAN bus so it is only design matter.
> > > > >
> > > > >
> > > > > Regards,
> > > > > Kevin.
> > > > >
> > > > > --- In l...
> > > ,
> > > > > Armand wrote:
> > > > > >
> > > > > > Hi Kevin,
> > > > > >
> > > > > > Although we are not using the LPC11C2x (we use the LPC1765),
you
> > > might
> > > > > > use the CAN driver TJA1041 for a wake up. The TJA1041 can be
put
> > > into
> > > > > > sleep mode, but as soon as CAN activity is detected then the
INH
> > > > > > pin will be going from "closed" to "open" (INH is an
internal FET).
> > > > > > The output of the INH pin with a possible level converter in
between
> > > > > > can be routed to an interrupt capable pin.
> > > > > >
> > > > > > I have not look thoroughly well on the TI site, but they
have
> > > similar
> > > > > > CAN drivers with less pins.
> > > > > >
> > > > > > Hopes this helps.
> > > > > >
> > > > > > Br,
> > > > > >
> > > > > > Armand
> > > > > >
> > > > > >
> > > > > > On 11/07/2012 06:07 AM, Kevin wrote:
> > > > > > > Hi all,
> > > > > > >
> > > > > > > Is there a way to have the LPC11C2x wakeup from a
low-power mode
> > > > > when there is any activity on the CANbus?
> > > > > > >
> > > > > > > Looking at the datasheets I cannot see a way to generate
an
> > > > > interrupt or wake-up event from the CAN RX signal, which has
no
> > > > > physical pin on this part. The RX signal is available in the
CANTEST
> > > > > register, but no interrupt seems to monitor this bit.
> > > > > > >
> > > > > > > Without this ability, it seems the entire C_CAN controller
must
> > > > > remaining running in order to detect traffic on the CANbus.
This puts
> > > > > a pretty large lower limit on the power consumption... :-(
> > > > > > >
> > > > > > > Anyone have any ideas?
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Kevin.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> >
> >
> >
> >
>
Thanks for your replies - I got sidetracked and only just got back to
looking at this now...
Re your suggestions about generating an interrupt from the CAN_RXD
signal, this is what I was trying to do, but the problem is that there
is no CAN_RXD pin to connect to a PIO and create a wakeup event. The
LPC11C24 has an integrated transceiver and does not make the RXD signal
available. Well, except as a bit in the CANTEST register, but there
doesn't appear to be a way to generate an int from this bit.
Re power consumption in automotive environments, in my experience
standby power is a critical issue. The LPC11 is the main Iq component at
the moment (I am having trouble getting it less than about 4mA). By the
time there are several of these in a system the whole thing can be
drawing >20mA when it's supposed to be asleep, which is too much to add
to the drain on the vehicle's battery when not operating for an extended
period.
I think I placed too much value on the integrated transceiver when I
chose the '11C24, and I may have to ditch it in favour of a 2-chip
solution :-(
But thanks again for your comments. Hope this thread can help someone
else planning a low power design with the LPC11 parts.
Kevin.
--- In l..., "praj1029" wrote:
>
> --- In l..., "M. Manca" wrote:
> >
> > Il 10/11/2012 04:38, praj1029 ha scritto:
> > >
> > >
> > >
> > >
> > > --- In l... , "M.
> > > Manca" wrote:
> > >
> > > Hi,
> > > This is possible. The procedure depends on the mode you are in.
> > >
> > > In Sleep mode (AS pointed to in Section 3.9.2 of the user manual):
The
> > > chip will wake up if any of the Vectored interrupts (explained in
> > > chapter) are asserted. The C_CAN interrupt is a Vectored
interrupt.
> > >
> > > In Deep Sleep mode (AS pointed to in Section 3.9.3 of the user
> > > manual): You can tie the CAN_RxD to any one of the pins PIO0_0 to
> > > PIO0_11 and PIO1_0 and then wake up the LPC11Cxx from Deep-sleep
mode.
> > > Section 3.9.3.3 explains the procedure in more detail.
> > >
> > This should be a viable solution only if he needs to detect the
traffic
> > on a low traffic bus because this system awake the microcontroller
every
> > time there is a transition edge on the CAN RXD pin and not when a
> > specific filered message is received. To implement this feature the
only
> > possibility offerede by this microcontroller is to put the
> > microcontroller in SLEEP MODE. Anyway I would like to point that
> > switching off the main PLL is a good practice to reduce also the
static
> > current consumption to a bare minimum value in sleep mode.
>
> You are correct, the deep sleep mode will wake up the chip regardless
of the filter settings. I was just presenting the options. Also, thank
you for pointing out the drawbacks.
> > >
> > >
> > > In Deep power down mode: You can tie the WAKEUP pin to the CAN_RxD
and
> > > wakeup the chip. A detailed description of the procedure to be
> > > followed is described in the section 3.9.4.3.
> > >
> > I don't believe this could be a real good solution because the
wakeup
> > pin accept impulses longer then 55ns then the cpu will go to reset
and
> > only the boot time is 55microseconds and you should add initial
> > stabilization time (it is not a fixed period) and application
> > initialization.
>
> Yes this solution would result in some complication because of the
time constraints that are to be taken care of.
>
> > >
> > >
> > > >
> > > > Il 08/11/2012 02:40, Kevin ha scritto:
> > > > >
> > > > >
> > > > > Hi Armand,
> > > > >
> > > > > Thanks for your reply, but the "nice" thing about the LPC11C2x
part is
> > > > > that is has an inbuilt CAN transceiver. So using an external
> > > > > transceiver invalidates the purpose of using the LPC11C2x in
the first
> > > > > place.
> > > > >
> > > > > Seems a bit of an oversight by NXP that they didn't allow
better
> > > > > interrupt/wakeup functionality when they integrated the CAN
:-(
> > > > >
> > > > In practice CAN is most used in automotive and industrial
applications
> > > > where the sleep mode offered by LPC11Cxx is perfectly adequate
and the
> > > > other most deeper sleep modes aren't very adequate because it is
better
> > > > to have the microcontroller really off.
> > > >
> > > > Remember that in automotive and industrial application the power
> > > > consumption due to the microcontroller is a little fraction
compared
> > > > with the rest of the board consumption.
> > > >
> > > > For other application I2C is a good candidate for multi
processor
> > > > communication bus both for inter board and board to board
communications
> > > > and you could also use it for "extreme" long distance
communications
> > > > with some care. Personally I achieved better long distance
results with
> > > > I2C then CAN bus so it is only design matter.
> > > > >
> > > > >
> > > > > Regards,
> > > > > Kevin.
> > > > >
> > > > > --- In l...
> > > ,
> > > > > Armand wrote:
> > > > > >
> > > > > > Hi Kevin,
> > > > > >
> > > > > > Although we are not using the LPC11C2x (we use the LPC1765),
you
> > > might
> > > > > > use the CAN driver TJA1041 for a wake up. The TJA1041 can be
put
> > > into
> > > > > > sleep mode, but as soon as CAN activity is detected then the
INH
> > > > > > pin will be going from "closed" to "open" (INH is an
internal FET).
> > > > > > The output of the INH pin with a possible level converter in
between
> > > > > > can be routed to an interrupt capable pin.
> > > > > >
> > > > > > I have not look thoroughly well on the TI site, but they
have
> > > similar
> > > > > > CAN drivers with less pins.
> > > > > >
> > > > > > Hopes this helps.
> > > > > >
> > > > > > Br,
> > > > > >
> > > > > > Armand
> > > > > >
> > > > > >
> > > > > > On 11/07/2012 06:07 AM, Kevin wrote:
> > > > > > > Hi all,
> > > > > > >
> > > > > > > Is there a way to have the LPC11C2x wakeup from a
low-power mode
> > > > > when there is any activity on the CANbus?
> > > > > > >
> > > > > > > Looking at the datasheets I cannot see a way to generate
an
> > > > > interrupt or wake-up event from the CAN RX signal, which has
no
> > > > > physical pin on this part. The RX signal is available in the
CANTEST
> > > > > register, but no interrupt seems to monitor this bit.
> > > > > > >
> > > > > > > Without this ability, it seems the entire C_CAN controller
must
> > > > > remaining running in order to detect traffic on the CANbus.
This puts
> > > > > a pretty large lower limit on the power consumption... :-(
> > > > > > >
> > > > > > > Anyone have any ideas?
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Kevin.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> >
> >
> >
> >
>
Reply by ●February 13, 20132013-02-13
