Channel Selection And Self-Diagnosis (Without Channel-Dedicated Sample-And-Hold Circuits) - Renesas RX100 Series User Manual

RX13T Group
26.3.3.3 Channel Selection and Self-Diagnosis (Without Channel-Dedicated Sample-
and-Hold Circuits)
When channels and self-diagnosis are selected at the same time, A/D conversion is first performed for the reference
voltage supplied to the 12-bit A/D converter, and then A/D conversion is performed on the analog input of the selected
channels, which sequence is repeated as below. In continuous scan mode, the internal reference voltage A/D conversion
select bit (S12AD.ADEXICR.OCSA) should be set to 0 (deselected).
(1) When the ADCSR.ADST bit is set to 1 (A/D conversion start) by software, or synchronous or asynchronous trigger
input, A/D conversion for self-diagnosis is started first.
(2) When A/D conversion for self-diagnosis is completed, the A/D conversion result is stored into the A/D self-
diagnosis data register (ADRD). A/D conversion is then performed for ANn channels selected by the ADANSA0
register, starting from the channel with the smallest number n.
(3) Each time A/D conversion of a single channel is completed, the A/D conversion result is stored into the
corresponding A/D data register (ADDRy).
(4) When A/D conversion of all the selected channels is completed, a scan end interrupt request is generated if the
ADCSR.ADIE bit is 1 (interrupt generation upon scanning completion enabled). At the same time, the 12-bit A/D
converter starts A/D conversion for self-diagnosis and then starts A/D conversion on ANn channels selected by the
ADANSA0 register, starting from the channel with the smallest number n.
(5) The ADCSR.ADST bit is not automatically cleared and steps 2 to 4 are repeated as long as the bit remains 1. When
the ADST bit is set to 0 (A/D conversion stop), A/D conversion stops and the 12-bit A/D converter enters a wait
state.
(6) When the ADCSR.ADST bit is later set to 1 (A/D conversion start), the A/D conversion for self-diagnosis is started
again.
A/D conversion
ADST
started
Reference
voltage
Waiting for
conversion
(x0, x½, x1)
Channel 1
Waiting for conversion
(AN001)
Channel 2
Waiting for conversion
(AN002)
ADRD
ADDR1
ADDR2
Scan end
interrupt
Note 1. indicates the instruction is executed by software.
Note 2. The converted data of A/D conversion 3 is ignored.
Figure 26.11 Example of Operation in Continuous Scan Mode
(Basic Operation; AN001 and AN002 Selected + Self-Diagnosis)
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
Self-diagnosis and scanning performed repeatedly
*1
Set
(1)
A/D conversion for self-
Waiting for conversion
diagnosis 1
A/D conversion 1
Stored
(2)
A/D conversion for self-diagnosis result 1
A/D
conversion time
A/D conversion for self-
diagnosis 2
Waiting for conversion
A/D conversion 2
(3)
A/D conversion result 1
(3)
A/D conversion result 2
(4)
Interrupt generated
26. 12-Bit A/D Converter (S12ADF)
Cleared Set
(6)
Waiting for
A/D conversion for self-
conversion
diagnosis 3
(5)
A/D conversion
Waiting for conversion
*2
3
Waiting for conversion
Stored
(2)
A/D conversion for self-diagnosis
result 2
Page 849 of 1041