M16C26A Datasheet, PDF (228/352 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/Tiny SERIES

M16C/26A Group (M16C/26A, M16C/26B, M16C/26T)
14. A/D Converter
14.2 Resolution Select Function
The BITS bit in the ADCON1 register determines the resolution. When the BITS bit is set to “1” (10-bit
precision), the A/D conversion result is stored into bits 0 to 9 in the A/D register i (i=0 to 7). When the BITS
bit is set to “0” (8-bit precision), the A/D conversion result is stored into bits 0 to 7 in the ADi register.
14.3 Sample and Hold
When the SMP bit in the ADCON 2 register is set to “1” (with the sample and hold function), A/D conver-
sion rate per pin increases to 28 φAD cycles for 8-bit resolution or 33 φAD cycles for 10-bit resolution. The
sample and hold function is available in one-shot mode, repeat mode, single sweep mode, repeat sweep
mode 0 and repeat sweep mode 1. In these modes, start A/D conversion after selecting whether the
sample and hold circuit is to be used or not. In simultaneous sample sweep mode, delayed trigger mode
0 or delayed trigger mode 1, set to use the Sample and Hold function before starting A/D conversion.
14.4 Power Consumption Reducing Function
When the A/D converter is not used, the VCUT bit in the ADCON1 register isolates the resistor ladder of
the A/D converter from the reference voltage input pin (VREF). Power consumption is reduced by shutting
off any current flow into the resistor ladder from the VREF pin.
When using the A/D converter, set the VCUT bit to “1” (VREF connected) before setting the ADST bit in the
ADCON0 register to “1” (A/D conversion started). Do not set the ADST bit and VCUT bit to “1” simulta-
neously, nor set the VCUT bit to “0” (VREF unconnected) during A/D conversion.
Rev. 2.00 Feb.15, 2007 ^{page 211} of 329
REJ09B0202-0200