I'm experiencing a series of problems with my current MSP-based design.
When the system is being turned "off", half of the supporting circuitry powers
off (including VCC for the MSP) while the other half remains powered (to retain
some logic states). I thought there may have been some leakage current going
into the MSP from the always-powered half of the system, and that it was causing
some damage to the MSP pin function control circuitry - causing the internal
pull up/down resistors to be enabled. I have added protection circuitry to
prevent any leakage into the MSP while VCC is off, but I'm still seeing
behavior that looks like the internal pull up/down resistors are being enabled.
I've made sure that the P1REN bits are cleared during initialization as
well as each time I clear the watchdog timer. It seems like the resistor
control circuit or some other part of the pin control circuit is being damaged
and is subsequently leaking current. I'm not sure about the damage part,
but the MSP is definitely leaking current when the pins are configured for ADC
input.
Does anybody have any ideas why this is happening?
thanks,
Aaron
MSP430F2012 - internal pull up/down resistors being enabled erroneously
Started by ●April 14, 2008
Reply by ●April 14, 20082008-04-14
There is a write up on this somewhere, I remember seeing it, but don't
recall exactly where. I have a feeling it was in the Old testament
(SLAA024!) probably under the hardware or FAQs section, but I couldn't
find it whe n I looked just now. baically it was discussing problems
related to channels configured for A/d that had a Logic level on them,
and even mixing pins on the same port between analog and digital. Sorr
can't remember where, but it was witin the last few days.
Al
Aaron Greer wrote:
>I'm experiencing a series of problems with my current MSP-based design. When the system is being turned "off", half of the supporting circuitry powers off (including VCC for the MSP) while the other half remains powered (to retain some logic states). I thought there may have been some leakage current going into the MSP from the always-powered half of the system, and that it was causing some damage to the MSP pin function control circuitry - causing the internal pull up/down resistors to be enabled. I have added protection circuitry to prevent any leakage into the MSP while VCC is off, but I'm still seeing behavior that looks like the internal pull up/down resistors are being enabled. I've made sure that the P1REN bits are cleared during initialization as well as each time I clear the watchdog timer. It seems like the resistor control circuit or some other part of the pin control circuit is being damaged and is subsequently leaking current. I'm not sure about the damage part, but the MSP is definitely leaking current when the pins are configured for ADC input.
>Does anybody have any ideas why this is happening?
>
>thanks,
>Aaron
>
>
recall exactly where. I have a feeling it was in the Old testament
(SLAA024!) probably under the hardware or FAQs section, but I couldn't
find it whe n I looked just now. baically it was discussing problems
related to channels configured for A/d that had a Logic level on them,
and even mixing pins on the same port between analog and digital. Sorr
can't remember where, but it was witin the last few days.
Al
Aaron Greer wrote:
>I'm experiencing a series of problems with my current MSP-based design. When the system is being turned "off", half of the supporting circuitry powers off (including VCC for the MSP) while the other half remains powered (to retain some logic states). I thought there may have been some leakage current going into the MSP from the always-powered half of the system, and that it was causing some damage to the MSP pin function control circuitry - causing the internal pull up/down resistors to be enabled. I have added protection circuitry to prevent any leakage into the MSP while VCC is off, but I'm still seeing behavior that looks like the internal pull up/down resistors are being enabled. I've made sure that the P1REN bits are cleared during initialization as well as each time I clear the watchdog timer. It seems like the resistor control circuit or some other part of the pin control circuit is being damaged and is subsequently leaking current. I'm not sure about the damage part, but the MSP is definitely leaking current when the pins are configured for ADC input.
>Does anybody have any ideas why this is happening?
>
>thanks,
>Aaron
>
>
Reply by ●April 14, 20082008-04-14
When Vcc is off, all the register settings are lost and do not have
any effect.
If some of the pins of that MSP430 is connected to live signals,
current will leak into MSP430. This may cause current to leak out of
other pins which are not connected to live signals.
Use a voltmeter to measure the voltage of each of the MSP430 pins
(including the Vcc pin.) There are only 16 pins!
--- In m..., Aaron Greer wrote:
>
> I'm experiencing a series of problems with my current MSP-based
design. When the system is being turned "off", half of the supporting
circuitry powers off (including VCC for the MSP) while the other half
remains powered (to retain some logic states). I thought there may
have been some leakage current going into the MSP from the
always-powered half of the system, and that it was causing some damage
to the MSP pin function control circuitry - causing the internal pull
up/down resistors to be enabled. I have added protection circuitry to
prevent any leakage into the MSP while VCC is off, but I'm still
seeing behavior that looks like the internal pull up/down resistors
are being enabled. I've made sure that the P1REN bits are cleared
during initialization as well as each time I clear the watchdog timer.
It seems like the resistor control circuit or some other part of the
pin control circuit is being damaged and is subsequently leaking
current. I'm not sure about the damage part, but the MSP is definitely
leaking current when the pins are configured for ADC input.
> Does anybody have any ideas why this is happening?
>
> thanks,
> Aaron
>
any effect.
If some of the pins of that MSP430 is connected to live signals,
current will leak into MSP430. This may cause current to leak out of
other pins which are not connected to live signals.
Use a voltmeter to measure the voltage of each of the MSP430 pins
(including the Vcc pin.) There are only 16 pins!
--- In m..., Aaron Greer wrote:
>
> I'm experiencing a series of problems with my current MSP-based
design. When the system is being turned "off", half of the supporting
circuitry powers off (including VCC for the MSP) while the other half
remains powered (to retain some logic states). I thought there may
have been some leakage current going into the MSP from the
always-powered half of the system, and that it was causing some damage
to the MSP pin function control circuitry - causing the internal pull
up/down resistors to be enabled. I have added protection circuitry to
prevent any leakage into the MSP while VCC is off, but I'm still
seeing behavior that looks like the internal pull up/down resistors
are being enabled. I've made sure that the P1REN bits are cleared
during initialization as well as each time I clear the watchdog timer.
It seems like the resistor control circuit or some other part of the
pin control circuit is being damaged and is subsequently leaking
current. I'm not sure about the damage part, but the MSP is definitely
leaking current when the pins are configured for ADC input.
> Does anybody have any ideas why this is happening?
>
> thanks,
> Aaron
>
Reply by ●April 14, 20082008-04-14
OCY,
I already took the measurements like you said, that is how I determined that current was in fact leaking into the MSP. The analog signals connected to P1.0 to P1.2 were live when the MSP was not, this caused current to leak into the MSP and out the VCC pin, causing other problems. I have added FETs and buffers to make sure no analog signals are live when the MSP is off. So that is no longer a problem. The problem now is that with the MSP fully powered, I'm still seeing what appears to be the internal pull up resistor being enabled or something else that is causing current to leave the MSP and distort the analog signal being measured. I'm trying to figure out why that is happening.
thanks for your suggestions,
Aaron
----- Original Message -----
From: "old_cow_yellow"
To: m...
Sent: Monday, April 14, 2008 5:33:42 PM (GMT-0700) America/Denver
Subject: [msp430] Re: MSP430F2012 - internal pull up/down resistors being enabled erroneously
When Vcc is off, all the register settings are lost and do not have
any effect.
If some of the pins of that MSP430 is connected to live signals,
current will leak into MSP430. This may cause current to leak out of
other pins which are not connected to live signals.
Use a voltmeter to measure the voltage of each of the MSP430 pins
(including the Vcc pin.) There are only 16 pins!
--- In m... , Aaron Greer wrote:
>
> I'm experiencing a series of problems with my current MSP-based
design. When the system is being turned "off", half of the supporting
circuitry powers off (including VCC for the MSP) while the other half
remains powered (to retain some logic states). I thought there may
have been some leakage current going into the MSP from the
always-powered half of the system, and that it was causing some damage
to the MSP pin function control circuitry - causing the internal pull
up/down resistors to be enabled. I have added protection circuitry to
prevent any leakage into the MSP while VCC is off, but I'm still
seeing behavior that looks like the internal pull up/down resistors
are being enabled. I've made sure that the P1REN bits are cleared
during initialization as well as each time I clear the watchdog timer.
It seems like the resistor control circuit or some other part of the
pin control circuit is being damaged and is subsequently leaking
current. I'm not sure about the damage part, but the MSP is definitely
leaking current when the pins are configured for ADC input.
> Does anybody have any ideas why this is happening?
>
> thanks,
> Aaron
>
I already took the measurements like you said, that is how I determined that current was in fact leaking into the MSP. The analog signals connected to P1.0 to P1.2 were live when the MSP was not, this caused current to leak into the MSP and out the VCC pin, causing other problems. I have added FETs and buffers to make sure no analog signals are live when the MSP is off. So that is no longer a problem. The problem now is that with the MSP fully powered, I'm still seeing what appears to be the internal pull up resistor being enabled or something else that is causing current to leave the MSP and distort the analog signal being measured. I'm trying to figure out why that is happening.
thanks for your suggestions,
Aaron
----- Original Message -----
From: "old_cow_yellow"
To: m...
Sent: Monday, April 14, 2008 5:33:42 PM (GMT-0700) America/Denver
Subject: [msp430] Re: MSP430F2012 - internal pull up/down resistors being enabled erroneously
When Vcc is off, all the register settings are lost and do not have
any effect.
If some of the pins of that MSP430 is connected to live signals,
current will leak into MSP430. This may cause current to leak out of
other pins which are not connected to live signals.
Use a voltmeter to measure the voltage of each of the MSP430 pins
(including the Vcc pin.) There are only 16 pins!
--- In m... , Aaron Greer wrote:
>
> I'm experiencing a series of problems with my current MSP-based
design. When the system is being turned "off", half of the supporting
circuitry powers off (including VCC for the MSP) while the other half
remains powered (to retain some logic states). I thought there may
have been some leakage current going into the MSP from the
always-powered half of the system, and that it was causing some damage
to the MSP pin function control circuitry - causing the internal pull
up/down resistors to be enabled. I have added protection circuitry to
prevent any leakage into the MSP while VCC is off, but I'm still
seeing behavior that looks like the internal pull up/down resistors
are being enabled. I've made sure that the P1REN bits are cleared
during initialization as well as each time I clear the watchdog timer.
It seems like the resistor control circuit or some other part of the
pin control circuit is being damaged and is subsequently leaking
current. I'm not sure about the damage part, but the MSP is definitely
leaking current when the pins are configured for ADC input.
> Does anybody have any ideas why this is happening?
>
> thanks,
> Aaron
>
Reply by ●April 14, 20082008-04-14
Al,
thanks for pointing me to this. I'll look through this and other app notes. Please post if you remember what doc you are thinking of.
thanks,
Aaron
----- Original Message -----
From: "Onestone"
To: m...
Sent: Monday, April 14, 2008 5:27:09 PM (GMT-0700) America/Denver
Subject: Re: [msp430] MSP430F2012 - internal pull up/down resistors being enabled erroneously
There is a write up on this somewhere, I remember seeing it, but don't
recall exactly where. I have a feeling it was in the Old testament
(SLAA024!) probably under the hardware or FAQs section, but I couldn't
find it whe n I looked just now. baically it was discussing problems
related to channels configured for A/d that had a Logic level on them,
and even mixing pins on the same port between analog and digital. Sorr
can't remember where, but it was witin the last few days.
Al
Aaron Greer wrote:
>I'm experiencing a series of problems with my current MSP-based design. When the system is being turned "off", half of the supporting circuitry powers off (including VCC for the MSP) while the other half remains powered (to retain some logic states). I thought there may have been some leakage current going into the MSP from the always-powered half of the system, and that it was causing some damage to the MSP pin function control circuitry - causing the internal pull up/down resistors to be enabled. I have added protection circuitry to prevent any leakage into the MSP while VCC is off, but I'm still seeing behavior that looks like the internal pull up/down resistors are being enabled. I've made sure that the P1REN bits are cleared during initialization as well as each time I clear the watchdog timer. It seems like the resistor control circuit or some other part of the pin control circuit is being damaged and is subsequently leaking current. I'm not sure abou t the damage part, but the MSP is definitely leaking current when the pins are configured for ADC input.
>Does anybody have any ideas why this is happening?
>
>thanks,
>Aaron
>
>
thanks for pointing me to this. I'll look through this and other app notes. Please post if you remember what doc you are thinking of.
thanks,
Aaron
----- Original Message -----
From: "Onestone"
To: m...
Sent: Monday, April 14, 2008 5:27:09 PM (GMT-0700) America/Denver
Subject: Re: [msp430] MSP430F2012 - internal pull up/down resistors being enabled erroneously
There is a write up on this somewhere, I remember seeing it, but don't
recall exactly where. I have a feeling it was in the Old testament
(SLAA024!) probably under the hardware or FAQs section, but I couldn't
find it whe n I looked just now. baically it was discussing problems
related to channels configured for A/d that had a Logic level on them,
and even mixing pins on the same port between analog and digital. Sorr
can't remember where, but it was witin the last few days.
Al
Aaron Greer wrote:
>I'm experiencing a series of problems with my current MSP-based design. When the system is being turned "off", half of the supporting circuitry powers off (including VCC for the MSP) while the other half remains powered (to retain some logic states). I thought there may have been some leakage current going into the MSP from the always-powered half of the system, and that it was causing some damage to the MSP pin function control circuitry - causing the internal pull up/down resistors to be enabled. I have added protection circuitry to prevent any leakage into the MSP while VCC is off, but I'm still seeing behavior that looks like the internal pull up/down resistors are being enabled. I've made sure that the P1REN bits are cleared during initialization as well as each time I clear the watchdog timer. It seems like the resistor control circuit or some other part of the pin control circuit is being damaged and is subsequently leaking current. I'm not sure abou t the damage part, but the MSP is definitely leaking current when the pins are configured for ADC input.
>Does anybody have any ideas why this is happening?
>
>thanks,
>Aaron
>
>
Reply by ●April 14, 20082008-04-14
What are the settings of the registers? What signals (digital in,
digital out, or analog in) are each pin connected to?
--- In m..., Aaron Greer wrote:
>
> OCY,
> I already took the measurements like you said, that is how I
determined that current was in fact leaking into the MSP. The analog
signals connected to P1.0 to P1.2 were live when the MSP was not, this
caused current to leak into the MSP and out the VCC pin, causing other
problems. I have added FETs and buffers to make sure no analog signals
are live when the MSP is off. So that is no longer a problem. The
problem now is that with the MSP fully powered, I'm still seeing what
appears to be the internal pull up resistor being enabled or something
else that is causing current to leave the MSP and distort the analog
signal being measured. I'm trying to figure out why that is happening.
>
> thanks for your suggestions,
> Aaron
>
> ----- Original Message -----
> From: "old_cow_yellow"
> To: m...
> Sent: Monday, April 14, 2008 5:33:42 PM (GMT-0700) America/Denver
> Subject: [msp430] Re: MSP430F2012 - internal pull up/down resistors
being enabled erroneously
>
> When Vcc is off, all the register settings are lost and do not have
> any effect.
>
> If some of the pins of that MSP430 is connected to live signals,
> current will leak into MSP430. This may cause current to leak out of
> other pins which are not connected to live signals.
>
> Use a voltmeter to measure the voltage of each of the MSP430 pins
> (including the Vcc pin.) There are only 16 pins!
>
> --- In m... , Aaron Greer wrote:
> >
> > I'm experiencing a series of problems with my current MSP-based
> design. When the system is being turned "off", half of the supporting
> circuitry powers off (including VCC for the MSP) while the other half
> remains powered (to retain some logic states). I thought there may
> have been some leakage current going into the MSP from the
> always-powered half of the system, and that it was causing some damage
> to the MSP pin function control circuitry - causing the internal pull
> up/down resistors to be enabled. I have added protection circuitry to
> prevent any leakage into the MSP while VCC is off, but I'm still
> seeing behavior that looks like the internal pull up/down resistors
> are being enabled. I've made sure that the P1REN bits are cleared
> during initialization as well as each time I clear the watchdog timer.
> It seems like the resistor control circuit or some other part of the
> pin control circuit is being damaged and is subsequently leaking
> current. I'm not sure about the damage part, but the MSP is definitely
> leaking current when the pins are configured for ADC input.
> > Does anybody have any ideas why this is happening?
> >
> > thanks,
> > Aaron
> >
>
digital out, or analog in) are each pin connected to?
--- In m..., Aaron Greer wrote:
>
> OCY,
> I already took the measurements like you said, that is how I
determined that current was in fact leaking into the MSP. The analog
signals connected to P1.0 to P1.2 were live when the MSP was not, this
caused current to leak into the MSP and out the VCC pin, causing other
problems. I have added FETs and buffers to make sure no analog signals
are live when the MSP is off. So that is no longer a problem. The
problem now is that with the MSP fully powered, I'm still seeing what
appears to be the internal pull up resistor being enabled or something
else that is causing current to leave the MSP and distort the analog
signal being measured. I'm trying to figure out why that is happening.
>
> thanks for your suggestions,
> Aaron
>
> ----- Original Message -----
> From: "old_cow_yellow"
> To: m...
> Sent: Monday, April 14, 2008 5:33:42 PM (GMT-0700) America/Denver
> Subject: [msp430] Re: MSP430F2012 - internal pull up/down resistors
being enabled erroneously
>
> When Vcc is off, all the register settings are lost and do not have
> any effect.
>
> If some of the pins of that MSP430 is connected to live signals,
> current will leak into MSP430. This may cause current to leak out of
> other pins which are not connected to live signals.
>
> Use a voltmeter to measure the voltage of each of the MSP430 pins
> (including the Vcc pin.) There are only 16 pins!
>
> --- In m... , Aaron Greer wrote:
> >
> > I'm experiencing a series of problems with my current MSP-based
> design. When the system is being turned "off", half of the supporting
> circuitry powers off (including VCC for the MSP) while the other half
> remains powered (to retain some logic states). I thought there may
> have been some leakage current going into the MSP from the
> always-powered half of the system, and that it was causing some damage
> to the MSP pin function control circuitry - causing the internal pull
> up/down resistors to be enabled. I have added protection circuitry to
> prevent any leakage into the MSP while VCC is off, but I'm still
> seeing behavior that looks like the internal pull up/down resistors
> are being enabled. I've made sure that the P1REN bits are cleared
> during initialization as well as each time I clear the watchdog timer.
> It seems like the resistor control circuit or some other part of the
> pin control circuit is being damaged and is subsequently leaking
> current. I'm not sure about the damage part, but the MSP is definitely
> leaking current when the pins are configured for ADC input.
> > Does anybody have any ideas why this is happening?
> >
> > thanks,
> > Aaron
> >
>
Reply by ●April 15, 20082008-04-15
Aaron Greer :
> I have added FETs and buffers to make sure no analog signals are
> live when the MSP is off.
> I'm still seeing
> what appears to be the internal pull up resistor being enabled or
> something else that is causing current to leave the MSP and
> distort the analog signal being measured. I'm trying to figure out
> why that is happening.
Maybe your external FET's are leaking now? Or your board?
Below <1uA I also have trouble sometimes; cleaning and/or drying the
board helps to find out that this is or is not the problem.
M.
> I have added FETs and buffers to make sure no analog signals are
> live when the MSP is off.
> I'm still seeing
> what appears to be the internal pull up resistor being enabled or
> something else that is causing current to leave the MSP and
> distort the analog signal being measured. I'm trying to figure out
> why that is happening.
Maybe your external FET's are leaking now? Or your board?
Below <1uA I also have trouble sometimes; cleaning and/or drying the
board helps to find out that this is or is not the problem.
M.
Reply by ●April 15, 20082008-04-15
Once I discovered that the MSP appeared to be leaking current, I removed all the
circuitry and protection FETs and placed a single 10K resistor from the ADC pin
to ground. There is about 40uA of current leaking out the ADC pin, producing a
voltage of 400mV, not ground (0V) as would be expected. This experiment made me
believe the problem was the MSP and not any leakage through FETs, etc.
I'll see if cleaning the board helps.
thanks,
Aaron
----- Original Message -----
From: "Matthias Weingart"
To: m...
Sent: Tuesday, April 15, 2008 1:43:20 AM (GMT-0700) America/Denver
Subject: [msp430] Re: Re: MSP430F2012 - internal pull up/down resistors being enabled erroneously
Aaron Greer < a...@qsicorp.com >:
> I have added FETs and buffers to make sure no analog signals are
> live when the MSP is off.
> I'm still seeing
> what appears to be the internal pull up resistor being enabled or
> something else that is causing current to leave the MSP and
> distort the analog signal being measured. I'm trying to figure out
> why that is happening.
Maybe your external FET's are leaking now? Or your board?
Below <1uA I also have trouble sometimes; cleaning and/or drying the
board helps to find out that this is or is not the problem.
M.
I'll see if cleaning the board helps.
thanks,
Aaron
----- Original Message -----
From: "Matthias Weingart"
To: m...
Sent: Tuesday, April 15, 2008 1:43:20 AM (GMT-0700) America/Denver
Subject: [msp430] Re: Re: MSP430F2012 - internal pull up/down resistors being enabled erroneously
Aaron Greer < a...@qsicorp.com >:
> I have added FETs and buffers to make sure no analog signals are
> live when the MSP is off.
> I'm still seeing
> what appears to be the internal pull up resistor being enabled or
> something else that is causing current to leave the MSP and
> distort the analog signal being measured. I'm trying to figure out
> why that is happening.
Maybe your external FET's are leaking now? Or your board?
Below <1uA I also have trouble sometimes; cleaning and/or drying the
board helps to find out that this is or is not the problem.
M.
Reply by ●April 17, 20082008-04-17
With I ADC I know one problem. To disable it, I have to use this
sequence:
ADC12CTL1=0;
ADC12CTL0=0;
ADC12CTL1=0;
ADC12CTL0=0;
Otherwise it will draw current from Vcc.
M.
Aaron Greer :
> Once I discovered that the MSP appeared to be leaking current, I
> removed all the circuitry and protection FETs and placed a single
> 10K resistor from the ADC pin to ground. There is about 40uA of
> current leaking out the ADC pin, producing a voltage of 400mV, not
> ground (0V) as would be expected. This experiment made me believe
> the problem was the MSP and not any leakage through FETs, etc.
> I'll see if cleaning the board helps. thanks,
> Aaron
>
> ----- Original Message -----
> From: "Matthias Weingart"
> To: m...
> Sent: Tuesday, April 15, 2008 1:43:20 AM (GMT-0700) America/Denver
> Subject: [msp430] Re: Re: MSP430F2012 - internal pull up/down
> resistors being enabled erroneously
>
> Aaron Greer < a...@qsicorp.com >:
>
>> I have added FETs and buffers to make sure no analog signals are
>> live when the MSP is off.
>> I'm still seeing
>> what appears to be the internal pull up resistor being enabled or
>> something else that is causing current to leave the MSP and
>> distort the analog signal being measured. I'm trying to figure
>> out why that is happening.
>
> Maybe your external FET's are leaking now? Or your board?
> Below <1uA I also have trouble sometimes; cleaning and/or drying
> the board helps to find out that this is or is not the problem.
>
> M.
>
sequence:
ADC12CTL1=0;
ADC12CTL0=0;
ADC12CTL1=0;
ADC12CTL0=0;
Otherwise it will draw current from Vcc.
M.
Aaron Greer :
> Once I discovered that the MSP appeared to be leaking current, I
> removed all the circuitry and protection FETs and placed a single
> 10K resistor from the ADC pin to ground. There is about 40uA of
> current leaking out the ADC pin, producing a voltage of 400mV, not
> ground (0V) as would be expected. This experiment made me believe
> the problem was the MSP and not any leakage through FETs, etc.
> I'll see if cleaning the board helps. thanks,
> Aaron
>
> ----- Original Message -----
> From: "Matthias Weingart"
> To: m...
> Sent: Tuesday, April 15, 2008 1:43:20 AM (GMT-0700) America/Denver
> Subject: [msp430] Re: Re: MSP430F2012 - internal pull up/down
> resistors being enabled erroneously
>
> Aaron Greer < a...@qsicorp.com >:
>
>> I have added FETs and buffers to make sure no analog signals are
>> live when the MSP is off.
>> I'm still seeing
>> what appears to be the internal pull up resistor being enabled or
>> something else that is causing current to leave the MSP and
>> distort the analog signal being measured. I'm trying to figure
>> out why that is happening.
>
> Maybe your external FET's are leaking now? Or your board?
> Below <1uA I also have trouble sometimes; cleaning and/or drying
> the board helps to find out that this is or is not the problem.
>
> M.
>
