Reply by old_cow_yellow●November 21, 20062006-11-21
Skylooroo,
You should have used 32.768kHz Watch Crystal, not 4 Mhz Crystal.
This way, you can use LPM3 while the Watchdog is running with ACLK.
The 4 MHz Crystal oscillator consumes a lot of power and takes a long
time to start. Use the DCO instead. It consumes less power and can be
stopped and started almost instantly. If the frequency of DCO is not
accurate enough for your application, you can use the crystal
controlled ACLK as a reference to calibrate it.
--- In m..., "Clifford Heath" wrote: >
> > When LPM3_mode,DCO clock is not working.Only ACLK is support of
> MSP430F122.
> > Do you have a idea when LPM3_mode ?
>
> That's how it's meant to work. The ACLK is left running so you can
wake > on a timer, as well as the other interrupts that work
on LPM4.
>
> What did you want to know about LPM3?
>
Reply by Clifford Heath●November 20, 20062006-11-20
> When LPM3_mode,DCO clock is not working.Only ACLK is
support of MSP430F122. > Do you have a idea when LPM3_mode ?
That's how it's meant to work. The ACLK is left running so you can
wake
on a timer, as well as the other interrupts that work on LPM4.
What did you want to know about LPM3?
Reply by old_cow_yellow●November 20, 20062006-11-20
Two typo's. Corrected and marked with *** below
--- In m..., "old_cow_yellow"
wrote: >
> Reply inserted below.
>
> --- In m..., "skylooroo" wrote:
> >
> > hi! everyone!
> >
> > I'm using watchdog reset of MSP430F122.
> > Anyway, watchdog reset is not working. i tested . When i setting
> > Watchdog registor then system immediately reset.
>
> You probably did not include the pass-world (0x5A00) and
> that will cause immediate reset.
>
> >
> > Watchdog reset time is determined. I want to use the 250msec or
> > 500msec .but device is determined 64msec per 4MHZ crystal
>
> If you use 4000kHz as the clock of Watchdog, the longest
> reset time will be 8.192msec (32768/4000).
>
> To get 250msec reset, the clock must be 131.072kHz (32768/250),
> 32.768kHz (8192/250), 2.048kHz (512/250), or 0.256kHz (64/250).
>
> To get 500msec reset, the clock must be 65.536kHz (32768/500),
> 16.384kHz (8192/500), 1.024kHz (512/500), or 0.128kHz (64/500).
>
> > I want to seclect watchdog reset time. how can registor setting ? or > > do you have idea? and how can i do ?
>
> You can set SMCLK to one of the above desired frequencies and
> use that as the source of the Watchdog clock.
>
> Use WDT=0x5A08 for reset time 32768/SMCLK.
> Use WDT=0x5A09 for reset time 8192/SMCLK.
> Use WDT=0x5A0A (***not 8***) for reset time 512/SMCLK.
> Use WDT=0x5A0B (***not 8***)for reset time 64/SMCL.
>
> To get such SMCLK, set SMCLk = DCO, DCO/2, DCO/4, or DCO/8
> and adjust DCO to 1*, 2*, 4*, or 8* the desired frequency.
>
> >> P.S : iar compiler 3.30a ACLK : 4MHZ XTAL : 4MHz
> >
> > please advice for me.
> >
> > Best Regards,
> > Ragon.
>
Reply by old_cow_yellow●November 20, 20062006-11-20
Reply inserted below.
--- In m..., "skylooroo" wrote: >
> hi! everyone!
>
> I'm using watchdog reset of MSP430F122.
> Anyway, watchdog reset is not working. i tested . When i setting
> Watchdog registor then system immediately reset.
You probably did not include the pass-world (0x5A00) and
that will cause immediate reset.
>
> Watchdog reset time is determined. I want to use the 250msec or
> 500msec .but device is determined 64msec per 4MHZ crystal
If you use 4000kHz as the clock of Watchdog, the longest
reset time will be 8.192msec (32768/4000).
To get 250msec reset, the clock must be 131.072kHz (32768/250),
32.768kHz (8192/250), 2.048kHz (512/250), or 0.256kHz (64/250).
To get 500msec reset, the clock must be 65.536kHz (32768/500),
16.384kHz (8192/500), 1.024kHz (512/500), or 0.128kHz (64/500).
> I want to seclect watchdog reset time. how can
registor setting ? or
> do you have idea? and how can i do ?
You can set SMCLK to one of the above desired frequencies and
use that as the source of the Watchdog clock.
Use WDT=0x5A08 for reset time 32768/SMCLK.
Use WDT=0x5A09 for reset time 8192/SMCLK.
Use WDT=0x5A08 for reset time 512/SMCLK.
Use WDT=0x5A08 for reset time 64/SMCL.
To get such SMCLK, set SMCLk = DCO, DCO/2, DCO/4, or DCO/8
and adjust DCO to 1*, 2*, 4*, or 8* the desired frequency.
>> P.S : iar compiler 3.30a ACLK : 4MHZ XTAL : 4MHz
>
> please advice for me.
>
> Best Regards,
> Ragon.
>
Reply by skylooroo●November 20, 20062006-11-20
hi! everyone!
I'm using watchdog reset of MSP430F122.
Anyway, watchdog reset is not working. i tested . When i setting
Watchdog registor then system immediately reset.
Watchdog reset time is determined. I want to use the 250msec or
500msec .but device is determined 64msec per 4MHZ crystal
I want to seclect watchdog reset time. how can registor setting ? or
do you have idea? and how can i do ?
