SH7050 Datasheet, PDF (474/841 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperH RISC engine Family/

Section 14 A/D Converter
14.4.4 External Triggering of A/D Conversion
A/D conversion can be externally triggered. To activate the A/D converter with an external trigger,
first set the pin functions with the PFC (pin function controller), then set the TRGE bit to 1 in the
A/D control register (ADCR). For the A/D0 converter module, also set the EXTRG bit in the A/D
trigger register (ADTRGR). When a low-level pulse is input to the ADTRG pin after these settings
have been made, the A/D converter detects the falling edge of the pulse and sets the ADST bit to
1. Figure 14.6 shows the timing for external trigger input.
The ADST bit is set to 1 one state after the A/D converter samples the falling edge on the ADTRG
pin. The timing from setting of the ADST bit until the start of A/D conversion is the same as when
1 is written into the ADST bit by software.
ADTRG pin sampled
φ
ADTRG input
ADST bit
ADST = 1
Figure 14.6 External Trigger Input Timing
Rev. 5.00 Jan 06, 2006 page 454 of 818
REJ09B0273-0500