R01UH0822EJ0100 Rev.1.00
Page 815 of 1041
Jul 31, 2019
RX13T Group
26. 12-Bit A/D Converter (S12ADF)
26.2.3
A/D Control Register (ADCSR)
Note 1. Starting A/D conversion using an external pin (asynchronous trigger)
Set the ADCSR.TRGE and EXTRG bits to 1 while a high-level signal is input to the external pin (ADTRG0#). Then, if the
ADTRG0# signal is changed to low, the falling edge is detected and the scan process is started. In this case, the pulse width of
the low-level input must be at least 1.5 clock cycles of PCLK.
ADCSR sets double trigger mode, A/D conversion start trigger; enables/disables scan end interrupt; selects the scan
mode; and starts or stops A/D conversion.
DBLANS[4:0] Bits (Double Trigger Channel Select)
The DBLANS[4:0] bits select one of the channels for A/D conversion data duplication in double trigger mode. The A/D
conversion results of the analog input of the channel selected by the DBLANS[4:0] bits are stored into the A/D data
register y when conversion is started by the first trigger, and into the A/D data duplication register when started by the
second trigger.
shows selection of the channel for double triggered operation.
When double trigger mode is selected, the channels selected by the ADANSA0 register are invalid, and the channel
selected by the DBLANS[4:0] bits is subjected to A/D conversion instead.
When double trigger mode is selected in group scan mode, double trigger mode operation is performed for group A only
and not performed for group B or C. Also, in double trigger mode, the analog inputs of multiple internal reference
voltage cannot be selected for group A, but can be selected for groups B and C.
The DBLANS[4:0] bits should be set while the ADST bit is 0. They should not be set simultaneously when 1 is written
to the ADST bit.
Address(es): S12AD.ADCSR 0008 9000h
b15
b14
b13
b12
b11
b10
b9
b8
b7
b6
b5
b4
b3
b2
b1
b0
ADST
ADCS[1:0]
ADIE
—
—
TRGE EXTRG DBLE GBADI
E
—
DBLANS[4:0]
Value after reset:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit
Symbol
Bit Name
Description
R/W
b4 to b0
Double Trigger
Channel Select
These bits select one analog input channel for double triggered
operation. The setting is only effective while double trigger mode is
selected.
R/W
b5
—
Reserved
This bit is read as 0. The write value should be 0.
R/W
b6
Group B Scan End
Interrupt Enable
0: Disables interrupt generation upon group B scan completion.
1: Enables interrupt generation upon group B scan completion.
R/W
b7
Double Trigger Mode
Select
0: Deselects double trigger mode.
1: Selects double trigger mode.
R/W
b8
Trigger Select*
0: A/D conversion is started by synchronous trigger.
1: A/D conversion is started by asynchronous trigger.
R/W
b9
Trigger Start Enable
0: Disables A/D conversion to be started by synchronous or
asynchronous trigger.
1: Enables A/D conversion to be started by synchronous or
asynchronous trigger.
R/W
b11, b10
—
Reserved
These bits are read as 0. The write value should be 0.
R/W
b12
Scan End Interrupt
Enable
0: Disables interrupt generation upon scan completion.
1: Enables interrupt generation upon scan completion.
R/W
b14, b13
Scan Mode Select
b14 b13
0 0: Single scan mode
0 1: Group scan mode
1 0: Continuous scan mode
1 1: Setting prohibited
R/W
b15
A/D Conversion Start
0: Stops A/D conversion process.
1: Starts A/D conversion process.
R/W