Channel Selection And Self-Diagnosis (With Channel-Dedicated Sample-And-Hold Circuits) - Renesas RX100 Series User Manual

RX13T Group
26.3.2.4 Channel Selection and Self-Diagnosis (With Channel-Dedicated Sample-and-
Hold Circuits)
When channels and self-diagnosis are selected and a channel-dedicated sample-and-hold circuit is used, sample-and-hold
operations are performed first, and A/D conversion is performed once for the reference voltage supplied to the 12-bit
A/D converter as below. After that, A/D conversion is performed only once on the analog input of the selected channels.
(1) Analog input sampling of all channels for which the channel-dedicated sample-and-hold circuits are to be used is
started when the ADCSR.ADST bit is set to 1 (A/D conversion start) by software, or synchronous or asynchronous
trigger input.
(2) A/D conversion for self-diagnosis is started after completion of sampling and holding.
(3) When A/D conversion for self-diagnosis is completed, A/D conversion result is stored into the A/D self-diagnosis
data register (ADRD), and A/D conversion is performed for ANn channels selected by the ADANSA0 register,
starting from the channel with the smallest number n.
(4) 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).
(5) 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 upon scanning completion enabled).
(6) The ADCSR.ADST bit remains 1 (A/D conversion start) during A/D conversion, and is automatically cleared to 0
when A/D conversion of all the selected channels is completed. Then the 12-bit A/D converter enters a wait state.
A/D conversion
ADST
started
Reference
voltage
(x0, x½, x1)
Channel 0
Waiting for conversion
(AN000)
Channel 2
Waiting for conversion
(AN002)
ADRD
ADDR0
ADDR2
Scan end
interrupt
Note 1. indicates the instruction is executed by software.
Figure 26.5 Example of Operation in Single Scan Mode
(Channel-Dedicated Sample-and-Hold Circuits Used: AN000, AN002 Selected + Self-Diagnosis)
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
Sampling-and-holding and scanning performed once
*1
Set
(1)
Sample-and-hold time A/D conversion time
A/D conversion for
Waiting for conversion (2)
self-diagnosis
Sampling Holding
Sampling
Waiting for conversion
A/D conversion 1 Waiting for conversion
Holding
A/D conversion 2
(3)
Stored
A/D conversion result for self-diagnosis
Stored (4)
A/D conversion result 1
26. 12-Bit A/D Converter (S12ADF)
(6)
Waiting for conversion
Stored (4)
A/D conversion result 2
(5)
Interrupt generated
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