TMS320F28388D: ADC channels select question

Hi Yifu,

It seems that you are referencing the 337BGA package based on the screen capture that you have provided.  Part indeed has 24 available ADC channels and you should be able to use all of the pins.  In the TMDSCNCD28388D schematics, all 24 channels are accessible from the headers.  

Yifu Chen said:

1. Does it mean I can pick them randomly if I am using single end signal? what if I configure 17 pins?

Yes, but you need to choose the corresponding ADC block where the channel you chose belongs to since you need to setup that ADC for channel selected, sampling time, trigger...etc.  For example, if you chose ADCIND0, you need to configure ADCD block and setup SOC to use channel 0.  The four ADC blocks are independent so you are not only limited to using 16 channels but all the available 24 channels in hardware.

Yifu Chen said:

2. If I am using differential input, according to TMDSCNCD28388D design file, it looks like if I pick A2 as P, N has to be A3, is it correct?

Yes, that is correct.

Yifu Chen said:

3. If I pick ADCINB2 as input, how can I know which pin it is among ADCIN0-15?

On the first diagram that you quoted above, it shows that the are 4 independent ADC blocks (ADCA,ADCB, ADCC, ADCD), each block has 16 analog channels (ADCIN0- ADCIN15), but not all of these are used.  Refer to the diagram above where it shows all 4 ADC blocks.ADCINB2 corresponds to ADCIN2 of module ADCB (second block in the schematics that is colored blue).

Yifu Chen said:

4. According to the picture below, the four ADC units are not the same, correct? A, B and D have 8 ADC inputs but C only has 6.

Yes, that is correct.  Note that channels 14 and 15 is common for all 4 ADC blocks.

Best regards,

Joseph