SH7058 Datasheet, PDF (687/1130 Pages) Renesas Technology Corp – Renesas SuperHTM RISC engine

17.4.4 External Triggering of A/D Conversion
The A/D converter can be activated by input of an external A/D conversion start trigger.
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), and set the
EXTRG bit to 1 in the A/D trigger register (ADTRGR). When a low level is input to the ADTRG
pin after these settings have been made, the A/D converter detects the falling edge of a pulse and
sets the ADST bit to 1. Figure 17.7 shows the timing for external trigger input.
The ADST bit is set to 1 two states 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.
pin sampled
CK
input
ADST bit
ADST = 1
Figure 17.7 External Trigger Input Timing
Rev. 3.0, 09/04, page 646 of 1086