R01UH0823EJ0100 Rev.1.00
Page 1588 of 1823
Jul 31, 2019
RX23W Group
44. 12-Bit A/D Converter (S12ADE)
44.3.2.4
A/D Conversion in Double Trigger Mode
In single scan mode with double trigger mode, single scan operation started by synchronous trigger is performed twice as
below.
Self-diagnosis should be deselected, and 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.
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. When the DBLE bit in ADCSR is set to 1, channel
selection using the ADANSA0 and ADANSA1 registers is invalid. In double trigger mode, synchronous triggers should
be selected using the ADSTRGR.TRSA[5:0] bits, the ADCSR.EXTRG bit should be set to 0, and the ADCSR.TRGE bit
should be set to 1. Software trigger should not be used.
(1) When the ADCSR.ADST bit is set to 1 (A/D conversion start) by synchronous trigger input, A/D conversion is
started on the single channel selected by the ADCSR.DBLANS[4:0] bits.
(2) When A/D conversion is completed, the A/D conversion result is stored into the corresponding A/D data register
(ADDRy).
(3) The ADST bit is automatically cleared to 0 and the 12-bit A/D converter enters a wait state. Here, an S12ADI0
interrupt request is not generated irrespective of the ADCSR.ADIE bit setting (S12ADI0 interrupt upon scanning
completion enabled).
(4) When the ADCSR.ADST bit is set to 1 (A/D conversion start) by the second trigger input, A/D conversion is started
on the single channel selected by the ADCSR.DBLANS[4:0] bits.
(5) When A/D conversion is completed, the A/D conversion result is stored into the A/D data duplication register
(ADDBLDR), which is exclusively used in double trigger mode.
(6) If the ADCSR.ADIE bit is 1 (S12ADI0 interrupt upon scanning completion enabled), an S12ADI0 interrupt request
is generated.
(7) The ADST bit remains 1 (A/D conversion start) during A/D conversion, and is automatically cleared to 0 when A/D
conversion is completed. Then the 12-bit A/D converter enters a wait state.
Figure 44.8
Example of Operation in Single Scan Mode (Double Trigger Mode Selected; AN003 Duplicated)
Waiting for conversion
ADST
A/D conversion
started
Channel 3
(AN003)
Waiting for conversion
ADDR3
ADDBLDR
A/D conversion 1
Set
(1)
Stored
A/D conversion result 1
A/D conversion result 2
A/D conversion time
A/D conversion
performed once
(2)
(6)
Waiting for conversion
Interrupt generated
(3)
Set
A/D conversion 2
A/D conversion time
Stored
(6)
(5)
(7)
(4)
Synchronous
trigger 0
A/D conversion
performed once
S12ADI0