SH7146 Datasheet, PDF (664/1022 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperH™ RISC engine Family

Section 15 A/D Converter (ADC)
15.4.5 A/D Converter Activation by MTU2 or MTU2S
The A/D converter can be independently activated by an A/D conversion request from the interval
timer of the MTU2 or MTU2S.
To activate the A/D converter by the MTU2 or MTU2S, first set the TRGE bit in the A/D
control/status register (ADCSR) to 1, and then set the A/D trigger select register (ADTSR). After
this register setting has been made, the ADST bit in ADCR is automatically set to 1 when an A/D
conversion request from the interval timer of the MTU2 or MTU2S occurs. The timing from
setting of the ADST bit until the start of A/D conversion is the same as when 1 is written to the
ADST bit by software.
15.4.6 External Trigger Input Timing
A/D conversion can be externally triggered. When the TRGE bit in the A/D control/status register
(ADCSR) is set to 1 while the A/D trigger select registers_0 and _1 (ADTSR_0 and ADTSR_1)
are set to external trigger pin input, external trigger input is enabled at the ADTRG pin. A falling
edge of the ADTRG pin sets the ADST bit to 1 in ADCR, starting A/D conversion. Other
operations, in both single and scan modes, are the same as when the ADST bit has been set to 1 by
software. Figure 15.3 shows the timing.
CK
ADTRG
External trigger
signal
ADST
Figure 15.3 External Trigger Input Timing
A/D conversion
Rev. 3.00 May 17, 2007 Page 620 of 974
REJ09B0229-0300