Hi,
We do have PCBs with TM4C1294 which do show
- no failure
- failure sometimes
- failure allways
Failure description:
- Comparator inputs are stable on 2V and 2,2V (no noise measurable with oscilloscope)
- the comparator sometimes announces false state
- after Reset OR
- after PowerUp
That's the code:
init ()
{
// ...
// -----------------------
// Set GPIO and Comparator
// -----------------------
// PORT P
SysCtlPeripheralEnable(SYSCTL_PERIPH_COMP0);
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOP);
while(!SysCtlPeripheralReady(SYSCTL_PERIPH_COMP0))
{
}
GPIOPinTypeComparator(GPIO_PORTP_BASE, (GPIO_PIN_0 | GPIO_PIN_1));
ComparatorRefSet(COMP_BASE, COMP_REF_OFF);
ComparatorConfigure(COMP_BASE, 0, COMP_TRIG_NONE | COMP_OUTPUT_NORMAL );
//...
}
void idle100HzCallback( xTimerHandle xTimer )
{
static uint32_t counter = 0;
bool b = ComparatorValueGet(COMP_BASE, 0);
gesSetLed2(1);
if (!b)
{
counter++;
// wait for 10 occurrencies
if (counter >= 10)
{
// Switch on test LED
gesSetLed3(1);
// Do Power down procedure
// ...
}
}
else
{
counter = 0;
}
}
// ...
}
In the Errata we coudn't find any hints.
Any idea what's wrong.
Thanks for your support.
Best regards,
Reto
