SH7014 Datasheet, PDF (443/754 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

14. Mid-Speed A/D Converter ⎯ SH7016, SH7017 ⎯
14.4.2 Scan Mode (SCAN = 1)
The scan mode is optimal for monitoring analog input of multiple channels (including channel 1).
A/D conversion is started from channel 1 (AN0 for CH2 = 0 and AN4 for CH1 = 1) of the group
when the ADST bit of the A/D control/status register (ADCSR) is set to 1 by the software or
external trigger input.
When multiple channels are selected, A/D conversion of channel 2 (AN1 or AN5) is initiated
immediately after completion of the channel 1 conversion.
A/D conversion is performed repeatedly on the selected channels until the ADST bit is cleared to
0. The results of conversion are transferred to and held in the ADDR registers for the relevant
channels.
To switch modes or analog input channels during A/D conversion, clear the ADST bit to 0 and
stop A/D conversion to avoid malfunction. After switching (mode/channel change and ADST bit
setting can be made at the same time), set ADST bit to 1 to restart A/D conversion from channel 1.
An example of operation in scan mode when three channels of group 0 (AN0 to AN2) are selected
for A/D conversion is shown in figure 14.4.
1. Set the operation mode to scan mode (SCAN = 1), set the scan group to group 0 (CH2 = 0), set
the analog channels to AN0 to AN2 (CH1 = 1, CH0 = 0), and then start A/D conversion
(ADST = 1).
2. When A/D conversion for channel 1 (AN0) is complete, A/D conversion result is transferred to
ADDRA.
Next, channel 2 (AN1) will automatically be selected and conversion will begin.
3. In the same manner, channel 3 (AN2) will be converted.
4. When conversion of all of the selected channels (AN0 to AN2) are complete, ADF will
become 1 and channel 1 (AN0) will again be selected and conversion will begin.
At this time, if the ADIE bit is set to 1, ADI interrupt request will occur after completing A/D
conversion.
5. Steps (2) to (4) will be repeated while ADST bit is set to 1.
A/D conversion will stop when setting the ADST bit to 0. When setting the ADST bit to 1,
A/D conversion will start again from channel 1 (AN0).
Rev.5.00 Sep. 27, 2007 Page 409 of 716
REJ09B0398-0500