R01UH0823EJ0100 Rev.1.00 Page 1549 of 1823
Jul 31, 2019
RX23W Group 44. 12-Bit A/D Converter (S12ADE)
44.2.11 A/D Control Extended Register (ADCER)
Note 1. The reference voltage refers to the voltage on the pin selected in the ADHVREFCNT register.
ADCER sets self-diagnosis mode, format of A/D data registers y (ADDRy), and automatic clearing of A/D data registers.
ACE Bit (A/D Data Register Automatic Clearing Enable)
The ACE bit enables or disables automatic clearing (all “0”) of ADDRy, ADRD, ADDBLDR, ADTSDR, or ADOCDR
after any of these registers have been read by the CPU, DTC, or DMACA. Automatic clearing of the A/D data register is
enabled to detect a failure which has not been updated in the A/D data register.
DIAGVAL[1:0] Bits (Self-Diagnosis Conversion Voltage Select)
These bits select the voltage value used in self-diagnosis voltage fixed mode. For details, refer to the descriptions of the
ADCER.DIAGLD bit.
Self-diagnosis should not be executed by setting the ADCER.DIAGLD bit to 1 when the ADCER.DIAGVAL[1:0] bits
are set to 00b.
DIAGLD Bit (Self-Diagnosis Mode Select)
The DIAGLD bit selects whether the three voltage values are rotated or the fixed voltage is used in self-diagnosis.
Setting this bit (ADCER.DIAGLD) to 0 allows conversion of the voltages in rotation mode where 0, the reference
voltage × 1/2, and the reference voltage are converted in this order. When self-diagnosis rotation mode is selected after a
reset, self-diagnosis is performed from 0 V. When self-diagnosis voltage fixed mode is selected, the fixed voltage
specified by the ADCER.DIAGVAL[1:0] bits is converted. In self-diagnosis voltage rotation mode, the self-diagnosis
voltage value does not return to 0 when scan conversion is completed. When scan conversion is restarted, therefore,
rotation starts at the voltage value following the previous value. If fixed mode is switched to rotation mode, rotation
starts at the fixed voltage value.
The DIAGLD bit should be set while the ADCSR.ADST bit is 0.
Address(es): S12AD.ADCER 0008 900Eh
b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
ADRFM
T
———DIAGM
DIAGL
D
DIAGVAL[1:0]——ACE—————
Value after reset:
0000000000000000
Bit Symbol Bit Name Description R/W
b4 to b0 — Reserved These bits are read as 0. The write value should be 0. R/W
b5 ACE A/D Data Register Automatic
Clearing Enable
0: Disables automatic clearing.
1: Enables automatic clearing.
R/W
b7, b6 — Reserved These bits are read as 0. The write value should be 0. R/W
b9, b8 DIAGVAL[1:0] Self-Diagnosis Conversion Voltage
Select
b9 b8
0 0: Setting prohibited in self-diagnosis voltage fixed
mode
0 1: Uses the voltage of 0 V for self-diagnosis.
1 0: Uses the reference voltage x 1/2 for self-diagnosis.*
1
1 1: Uses the reference voltage for self-diagnosis.*
1
R/W
b10 DIAGLD Self-Diagnosis Mode Select 0: Rotation mode for self-diagnosis voltage
1: Fixed mode for self-diagnosis voltage
R/W
b11 DIAGM Self-Diagnosis Enable 0: Disables self-diagnosis of 12-bit A/D converter.
1: Enables self-diagnosis of 12-bit A/D converter.
R/W
b14 to b12 — Reserved These bits are read as 0. The write value should be 0. R/W
b15 ADRFMT A/D Data Register Format Select 0: Flush-right is selected for the A/D data register format.
1: Flush-left is selected for the A/D data register format.
R/W
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