Datasheet

Section 24 A/D Converter
REJ09B0465-0300 Rev. 3.00 Page 835 of 982
Sep 17, 2010
H8S/20103, H8S/20203, H8S/20223, H8S/20115, H8S/20215, H8S/20235 Group
24.4.2 Scan Mode in A/D Conversion Mode
In scan mode in A/D conversion mode, A/D conversion is to be performed sequentially on the
specified channels: maximum four channels or maximum eight channels. Operations are as
follows.
1. When the ADST bit in ADCSR is set to 1 by a software, timer RC, timer RD or external
trigger input, A/D conversion starts on the first channel of the channel set.
The consecutive A/D conversion on maximum four channels (SCANE = 1 and SCANS = 0) or
on maximum eight channels (SCANE = 1 and SCANS = 1) can be selected. When the
consecutive A/D conversion is performed on the four channels, the A/D conversion starts on
AN0 when CH3 = 0 and CH2 =0, AN4 when CH3 = 0 and CH2 = 1, or AN8 when CH3 = 1
and CH2 = 0. When the consecutive A/D conversion is performed on the eight channels, the
A/D conversion starts on AN0 when CH3 = 0 and CH2 = 0.
2. When A/D conversion for each channel is completed, the result is sequentially transferred to
the A/D data register corresponding to each channel.
3. When conversion of all the selected channels is completed, the ADF bit in ADCSR is set to 1.
If the ADIE bit is set to 1 at this time, an ADI interrupt is requested. The A/D conversion starts
again from the first channel of the channel set again.
4. The ADST bit is not cleared automatically, and steps [2] to [3] are repeated as long as the
ADST bit remains set to 1. When the ADST bit is cleared to 0, A/D conversion stops and the
A/D converter enters wait state. If the ADST bit is later set to 1, A/D conversion starts again
from the first channel of the channel set.