R01UH0823EJ0100 Rev.1.00 Page 1592 of 1823
Jul 31, 2019
RX23W Group 44. 12-Bit A/D Converter (S12ADE)
44.3.4.2 A/D Conversion in Double Trigger Mode
When double trigger mode is selected in group scan mode, two rounds of single scan operation started by a synchronous
trigger are performed as a sequence for group A. For group B, single scan operation started by a synchronous trigger is
performed once.
In group scan mode, the synchronous triggers of group A and B can be selected using the TRSA[5:0] and TRSB[5:0] bits
in ADSTRGR, respectively. The different triggers should be used for group A and group B to prevent simultaneous A/D
conversion of group A and group B. Software trigger and asynchronous trigger should not be used.
The group A and group B channels to be A/D-converted are selected using the ADCSR.DBLANS[4:0] bits and the
ADANSB0 and ADANSB1 registers, respectively. The same channels cannot be selected for both groups.
In group scan mode, the temperature sensor output A/D conversion select bit (ADEXICR.TSSA) and the internal
reference voltage A/D conversion select bit (ADEXICR.OCSA) should be set to 0 (deselected).
When double trigger mode is selected in group scan mode, self-diagnosis cannot be selected.
Duplication of A/D conversion data is enabled by setting the channel numbers to be duplicated to the
ADCSR.DBLANS[4:0] bits and setting the ADCSR.DBLE bit to 1.
The following describes operation in group scan mode with double trigger mode using a synchronous trigger from the
MTU. The TRG4ABN and TRG0AN triggers from the MTU are assumed to be used to start conversion of group A and
group B, respectively.
(1) Scanning of group B is started by the TRG0AN trigger from the MTU.
(2) When group B scanning is completed, a GBADI interrupt is generated if the ADCSR.GBADIE bit is 1 (GBADI
interrupt upon scanning completion enabled).
(3) The first scanning of group A is started by the first TRG4ABN trigger from the MTU.
(4) When the first scanning of group A is completed, the conversion result is stored into the corresponding A/D data
register (ADDRy); an S12ADI0 interrupt request is not generated irrespective of the ADIE bit setting in ADCSR.
(5) The second scanning of group A is started by the second TRG4ABN trigger from the MTU.
(6) When the second scanning of group A is completed, the conversion result is stored into ADDBLDR. An S12ADI0
interrupt is generated if the ADCSR.ADIE bit is 1 (S12ADI0 interrupt upon scanning completion enabled).
Figure 44.12 Example of Operation in Group Scan Mode with Double Trigger Mode
(Basic Operation: Synchronous Triggers from MTU Used)
TRG0AN event
TRG4ABN event
TRG4ABN
TRG0AN
Group B scanned
GBADI interrupt
Timer count
(1)
(3)
(4)
(5)
Group A
scanned
Group A
scanned
(6)
(2)
Group B scanned
Double trigger mode
Time
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