SH7108 Datasheet, PDF (372/560 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

Section 11 A/D Converter
Bit Bit Name Initial Value R/W Description
1
TRG0S1 0
R/W AD Trigger 0 Select 1 and 0
0
TRG0S0 0
R/W Enable the start of A/D conversion by A/D0 with a
trigger signal.
00: A/D conversion start by external trigger pin
(ADTRG) or MTU trigger is enabled
01: A/D conversion start by external trigger pin
(ADTRG) is enabled
10: A/D conversion start by MTU trigger is enabled
11: A/D conversion start by MMT trigger is enabled
When changing the operating mode, first clear the
TRGE and ADST bits in the A/D control registers
(ADCRs) to 0.
11.4 Operation
The A/D converter operates by successive approximation with 10-bit resolution. It has two
operating modes; single mode and scan mode. There are two kinds of scan mode: continuous
mode and single-cycle mode. When changing the operating mode or analog input channel, in order
to prevent incorrect operation, first clear the ADST bit to 0 in ADCR. The ADST bit can be set at
the same time when the operating mode is changed.
11.4.1 Single Mode
In single mode, A/D conversion is to be performed only once on the specified single channel. The
operations are as follows.
1. A/D conversion is started when the ADST bit in ADCR is set to 1, according to software,
MTU, MMT, or external trigger input.
2. When A/D conversion is completed, the result is transferred to the A/D data register
corresponding to the channel.
3. On completion of conversion, 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 remains set to 1 during A/D conversion. When A/D conversion ends, the ADST
bit is automatically cleared to 0 and the A/D converter enters the idle state.
When the ADST bit is cleared to 0 during A/D conversion, A/D conversion stops and the A/D
converter enters the idle state.
Rev.1.00 Sep. 18, 2008 Page 338 of 522
REJ09B0069-0100