I have used ADC0 pin to convert Analog value to Digital .
Voltage range given on ADC0 pin: 300mV to 2V using potentiometer
I have used example program(example_adc.c) given in OpenCPU SDK V2.4 for M66 EVB.
The values shown in debug monitor are fixed to 1.3-1.5V regardless of change in voltage at ADC0 pin.
I suspect the issue is due to the fact that M66 has Reference Voltage pin AVDD (Pin No8) which needs to be given 2.8V to function the ADC properly. But I could not find the Pin brought on EVB which is AVDD pin on M66. Currently, AVDD pin on M66 has 0 Voltage internally.
How to get the ADC working properly? What needs to be done on Hardware / software level?
Thank you.
Where did you buy your EVB board, you can consult the use of the board.In theory, the use of ADC must ensure that the reference voltage has a voltage value and is stable.No special processing is required on the software.
Yes , Reference voltage should be there to get the ADC working. But on my board the AVDD pin on M66 gives 0 voltage when measured.
I would like to bring it to notice that :
The ADC0 Pin on M66 module was not linked/connected to ADC0 pin on EVB (GSM - EVB Q1-A0543)
The resistor R121 which needs to be in place in order to connect the ADC0 pin on M66 to ADC0 pin on EVB, is not present on the TE-A module which I have currently.
I had to attach the ADC voltage pin directly to R121 pad and then only the ADC was working properly.
Thank you.