R01UH0823EJ0100 Rev.1.00
Page 1612 of 1823
Jul 31, 2019
RX23W Group
44. 12-Bit A/D Converter (S12ADE)
44.3.10
Starting A/D Conversion with Asynchronous Trigger
The A/D conversion can be started by the input of an asynchronous trigger. To start up the A/D converter by an
asynchronous trigger, the A/D conversion start trigger select bits (ADSTRGR.TRSA[5:0]) should be set to 000000b, and
a high-level signal should be input to the asynchronous trigger (ADTRG0# pin). Then, the ADCSR.TRGE and
ADCSR.EXTRG bits should be set to 1.
shows a timing of the asynchronous trigger input.
For the time from when the ADST bit is set to 1 until conversion starts, refer to
section 44.8.3, A/D Conversion
Restarting Timing and Termination Timing
. An asynchronous trigger cannot be selected for group B used in group
scan mode.
Figure 44.27
Timing of Sampling Asynchronous Trigger
44.3.11
Starting A/D Conversion with Synchronous Trigger from Peripheral Module
The A/D conversion can be started by a synchronous trigger. To start the A/D conversion by a synchronous trigger, the
ADCSR.TRGE bit should be set to 1, the ADCSR.EXTRG bit should be cleared to 0, and the relevant sources should be
selected by the ADSTRGR.TRSA[5:0] and ADSTRGR.TRSB[5:0] bits.
44.4
Interrupt Sources and DTC/DMAC Transfer Requests
44.4.1
Interrupt Requests
The 12-bit A/D converter can send scan end interrupt requests S12ADI0 and GBADI to the CPU.
Setting the ADCSR.ADIE bit to 1 and 0 enables and disables an S12ADI0 interrupt, respectively; similarly, setting the
ADCSR.GBADIE bit to 1 and 0 enables and disables a GBADI interrupt, respectively.
In addition, the DTC or DMACA can be activated when an S12ADI0 or a GBADI interrupt is generated. Using an
S12ADI0 or a GBADI interrupt to allow the DTC or DMACA to read the converted data enables continuous conversion
without burden on software.
For details on DTC settings, see
section 19, Data Transfer Controller (DTCa)
, and for details on DMACA settings,
see
section 18, DMA Controller (DMACA)
.
Timing of sampling the asynchronous trigger
Asynchronous trigger
PCLK
ADST bit
4 states
Internal trigger signal