SH7261 datasheet(1052/1348 Pages) RENESAS

1052 / 1348 page

Section 22 A/D Converter (ADC)

Rev. 2.00 Sep. 07, 2007 Page 1020 of 1312

REJ09B0320-0200

22.4

Operation

The A/D converter uses the successive-approximation method, and the resolution is 10 bits. It has

three operating modes: single mode, multi mode, and scan mode. Switching the operating mode or

analog input channels must be done while the ADST bit in ADCSR is 0 to prevent incorrect

operation. The ADST bit can be set at the same time as the operating mode or analog input

channels are changed.

22.4.1

Single Mode

Single mode should be selected when only A/D conversion on one channel is required.

In single mode, A/D conversion is performed once for the specified one analog input channel, as

follows:

1. A/D conversion for the selected channel starts when the ADST bit in ADCSR is set to 1 by

software, MTU2, TMR, or external trigger input.

2. When A/D conversion is completed, the A/D conversion result is transferred to the A/D data

3. After A/D conversion has completed, the ADF bit in ADCSR is set to 1. If the ADIE bit is set

to 1 at this time, an ADI interrupt request is generated.

4. The ADST bit that remains 1 during A/D conversion is automatically cleared to 0 when A/D

conversion is completed, and the A/D converter becomes idle.

When the operating mode or analog input channel selection must be changed during A/D

conversion, to prevent incorrect operation, first clear the ADST bit to 0 to halt A/D conversion.

After making the necessary changes, set the ADST bit to 1 to start A/D conversion again. The

ADST bit can be set at the same time as the mode or channel selection is switched.

SH7261 Datasheet(PDF) 1052 Page - Renesas Technology Corp