Continuous Scan Mode; Basic Operation (Without Channel-Dedicated Sample And-Hold Circuits) - Renesas RX100 Series User Manual

RX13T Group
26.3.3

Continuous Scan Mode

26.3.3.1

Basic Operation (Without Channel-Dedicated Sample and-Hold Circuits)

In basic operation of continuous scan mode, A/D conversion is performed repeatedly on the analog input of the specified
channels 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 is performed for ANn channels selected by the ADANSA0 register, starting from the channel
with the smallest number n.
(2) 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).
(3) 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).
The 12-bit A/D converter sequentially starts A/D conversion for ANn channels selected by the ADANSA0 register,
starting from the channel with the smallest number n.
(4) The ADCSR.ADST bit is not automatically cleared to 0 and steps 2 and 3 are repeated as long as the bit remains 1
(A/D conversion start). When the ADCSR.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.
(5) When the ADST bit is later set to 1 (A/D conversion start), A/D conversion is started again for ANn channels
selected by the ADANSA0 register, starting from the channel with the smallest number n.
A/D conversion
ADST
started
Channel 0
Waiting for
(AN000) conversion
Channel 1
Waiting for conversion
(AN001)
Channel 2
Waiting for conversion
(AN002)
ADDR0
ADDR1
ADDR2
Scan end
interrupt
Note 1. indicates the instruction is executed by software.
Note 2. The converted data of A/D conversion 5 is ignored.
Figure 26.9 Example of Operation in Continuous Scan Mode (Basic Operation: AN000 to AN002 Selected)
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
A/D conversion repeated
1
Set*
(1)
A/D conversion 1 Waiting for conversion
A/D conversion 2
(2)
Stored
A/D conversion result 1
(2)
A/D conversion time
A/D conversion 4
Waiting for conversion
A/D conversion 3
A/D conversion result 2
(2)
A/D conversion result 3
(3)
Interrupt generated
26. 12-Bit A/D Converter (S12ADF)
Cleared Set
(5)
Waiting for conversion A/D conversion 6
(4)
2
*
A/D conversion 5 Waiting for conversion
Waiting for conversion
(2)
Stored
A/D conversion result 4
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