32.1.2 Channel Selection

The ADPCH32.7.8 ADPCH register determines which channel is connected to the Sample-and-Hold circuit.

There are several channel selections available as shown in the following selection table:

Table 32-1. ADC Positive Input Channel Selections
ADPCH ADC Positive Channel Input
111111 Fixed Voltage Reference (FVR)(2)
111110 DAC1 output(1)
111101 Temperature Indicator(3)
111100 AVSS (Analog Ground)
100011 to 111000 Reserved. No channel connected.
110111 RG7/ANG7
110110 RG6/ANG6
110101 RG5/ANG5
110100 RG4/ANG4
110011 RG3/ANG3
110010 RG2/ANG2
110001 RG1/ANG1
110000 RG0/ANG0
101111 Reserved. No channel connected
101110 RF6/ANF6
101101 RF5/ANF5
101100 RF4/ANF4
101011 Reserved. No channel connected
101010 RF2/ANF2
101001 RF1/ANF1
101000 Reserved. No channel connected
100111 RE7/ANE7
100110 RE6/ANE6
100101 RE5/ANE5
100100 RE4/ANE4
100011 RE3/ANE3
100010 RE2/ANE2
100001 RE1/ANE1
100000 RE0/ANE0
011111 RD7/AND7
011110 RD6/AND6
011101 RD5/AND5
011100 RD4/AND4
011011 RD3/AND3
011010 RD2/AND2
011001 RD1/AND1
011000 RD0/AND0
010111 to 010000 Reserved. No channel connected
001111 RB7/ANB7
001110 RB6/ANB6
001101 RB5/ANB5
001100 RB4/ ANB4
001011 RB3/ANB3
001010 RB2/ ANB2
001001 RB1/ ANB1
001000 RB0/ANB0
000111 RA7/ANA7
000110 RA6/ANA6
000101 RA5/ANA5
000100 RA4/ ANA4
000011 RA3/ ANA3
000010 RA2/ ANA2
000001 RA1/ ANA1
000000 RA0/ANA0

When changing channels, a delay is required before starting the next conversion.

Refer to the “ADC Operation” section for more information.

Important: It is recommended to discharge the Sample-and-Hold capacitor when switching between ADC channels by starting a conversion on a channel connected to VSS and terminating the conversion after the acquisition time has elapsed. If the ADC does not have a dedicated VSS input channel, the VSS selection (DAC1R[4:0] = b'00000') through the DAC output channel can be used. If the DAC is in use, a free input channel can be connected to VSS, and can be used in place of the DAC.