Tool/software:
I use BOCS to detect broken sensors and observe unexpected behavior.
I proceed as follows: (very simplified example)
while(1){
INPMUX to Ch0(+) / Ch1(-) // set channel
System Control Register = 0b11110000 (BOCS = 10uA) // switch on BOCS
start_ADC() // start acquisition
while (not(DRDY)){} // takes about 100ms
read_out_ADC()
System Control Register = 0b00010000 // switch off BOCS
}
But the inputs are not pulled to VDD and VSS.
But if I set a delay before the acquisition, it works:
while(1){
INPMUX to Ch0(+) / Ch1(-) // set channel
System Control Register = 0b11110000 (BOCS = 10uA) // switch on BOCS
start_ADC() // start acquisition
while (not(DRDY)){} // takes about 100ms
read_out_ADC()
System Control Register = 0b00010000 // switch off BOCS
}
This gives me the impression that BOCS is disconnected from the MUX (AIN0 and AIN2) during the acquisition.
Can you confirm this?
I have a 100nF CAP capacitance between AIN0 and AIN1.
I would expect this to charge up within the loop and maintain the voltage, even without the delay(5ms) before start_ADC(). But the longer the delay, the faster the CAP charges
