M16C30P_07 Datasheet, PDF (298/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
22. Usage Precaution
If the CPU reads the ADi register (i = 0 to 7) at the same time the conversion result is stored in the ADi register
after completion of A/D conversion, an incorrect value may be stored in the ADi register. This problem occurs
when a divide-by-n clock derived from the main clock or a subclock is selected for CPU clock.
• When operating in one-shot mode
Check to see that A/D conversion is completed before reading the target ADi register. (Check the IR bit in
the ADIC register to see if A/D conversion is completed.)
• When operating in repeat mode
Use the main clock for CPU clock directly without dividing it.
If A/D conversion is forcibly terminated while in progress by setting the ADST bit in the ADCON0 register to “0”
(A/D conversion halted), the conversion result of the A/D converter is indeterminate. The contents of ADi registers
irrelevant to A/D conversion may also become indeterminate. If while A/D conversion is underway the ADST bit is
cleared to “0” in a program, ignore the values of all ADi registers.
The applied intermediate potential may cause more increase in power consumption than other analog input pins
(AN0 to AN3 and AN0_0 to AN0_7), since the AN4 to AN7 are used with the KI0 to KI3.
Rev.1.22 Mar 29, 2007 Page 282 of 291
REJ09B0179-0122