Hi, my name is Bence Kovari from Hungary. I have an FRDM-KEAZ128 board (80 LQFP package). Iam doing ADC, and i would like to use an External Voltage source as Analog Reference. The way i tried: I've checked my Header/Pinout, and connected my own voltage (in this case 1V) to AREF pin, and gnd to gnd (just one pin below AREF). I coded the initialization structure, ADC_Init() etc (works fine so far). I add the line to the code to select external VREF:
Then i read the channel ADC_CHANNEL_AD29_VREFH that should show my own external voltage,
but nothing happens. It's still 5V, the internal ref regardless. I've also tried:
ADC_SC2 |=ADC_SC2_REFSEL(0b01); (which i copied from an example source code).
I've checked the Reference manual that describes this topic quite shortly and messy a bit. Or i may have misunderstood something in the vref schematics or channel/pins description. So please if you could tell me how to do this stuff correctly i would really appreciate that!