2.3.3 Wrong VDD Scaler Reference with CMP0 and CMP1 Enabled Concurrently
The wrong VDD scaler reference voltage is observed when AC_CMP0 and AC_CMP1 are enabled concurrently with VDD scaler as the reference for both the comparators. Both the comparators will see the same VDD scaler reference.
Work Around:
For A0, use the following equation to get the VScale for AC_CMP0 and AC_CMP1.
R_Bottom = R_Bottom of configured SCALER1.VALUE[3:0]
R_Total = 900 – abs([598.5 – R_Bottom])
VScale = VDD. (598.5)/R_Total if R_bottom >= 598.5
VScale = VDD.(R_Bottom/R_Total) if R_bottom < 598.5
Note:
This workaround is only applicable to A0 revision and does not work in A2 revision. In A2, CMP0 and CMP1 uses independent scaler references as per the data sheet.
CMP0 uses a fixed reference VDD/2. CMP1 uses a variable reference configured using SCALER1.VALUE[3:0].Affected Silicon Revisions
PIC32CX1012BZ25048/WBZ451/WBZ451H| A0 | A2 | |||||
|---|---|---|---|---|---|---|
| X |
| A2 | |||||
|---|---|---|---|---|---|