R01UH0823EJ0100 Rev.1.00
Page 1531 of 1823
Jul 31, 2019
RX23W Group
44. 12-Bit A/D Converter (S12ADE)
Table 44.1
Specifications of 12-Bit A/D Converter (1/2)
Item
Description
Number of units
One unit
Input channels
Up to 14 channels
Extended analog function Temperature sensor output, internal reference voltage
A/D conversion method
Successive approximation method
Resolution
12 bits
Conversion time
0.83 μs per channel
(when A/D conversion clock ADCLK = 54 MHz)
A/D conversion clock
Peripheral module clock PCLK*
and A/D conversion clock ADCLK*
can be set so that the frequency ratio
should be one of the following.
PCLK to ADCLK frequency ratio = 1:1, 1:2, 2:1, 4:1, 8:1
ADCLK is set using the clock generation circuit.
Data registers
14 registers for analog input, 1 for A/D-converted data duplication in double trigger mode
One register for temperature sensor output
One register for internal reference voltage
One register for self-diagnosis
The results of A/D conversion are stored in 12-bit A/D data registers.
12-bit accuracy output for the results of A/D conversion
The value obtained by adding up A/D-converted results is stored as a value in the number of bit for
conversion ac 2 bits/4 bits*
in the A/D data registers in A/D-converted value addition mode.
Double trigger mode (selectable in single scan and group scan modes):
The first piece of A/D-converted analog-input data on one selected channel is stored in the data register
for the channel, and the second piece is stored in the duplication register.
Operating modes
Single scan mode:
A/D conversion is performed only once on the analog inputs of up to 14 channels arbitrarily selected.
A/D conversion is performed only once on the temperature sensor output.
A/D conversion is performed only once on the internal reference voltage.
Continuous scan mode:
A/D conversion is performed repeatedly on the analog inputs of up to 14 channels arbitrarily selected.
Group scan mode:
Analog inputs of up to 14 channels arbitrarily selected, are divided into group A and group B, and A/D
conversion of the analog input selected on a group basis is performed only once.
The conditions for scanning start of group A and group B (synchronous trigger) can be independently
selected, thus allowing A/D conversion of group A and group B to be started independently.
Group scan mode (when group A is given priority):
If a group A trigger is input during A/D conversion on group B, the A/D conversion on group B is stopped
and A/D conversion is performed on group A.
Restart (rescan) of A/D conversion on group B after completion of A/D conversion on group A can be set.
Conditions for A/D
conversion start
Software trigger
Synchronous trigger
Trigger by the multi-function timer pulse unit (MTU), the event link controller (ELC), or the 16-bit timer
pulse unit (TPU).
Asynchronous trigger
A/D conversion can be triggered by the external trigger ADTRG0# pin.
Functions
Variable sampling state count
Self-diagnosis of 12-bit A/D converter
Selectable A/D-converted value addition mode or average mode
Analog input disconnection detection function (discharge function/precharge function)
Double trigger mode (duplication of A/D conversion data)
Automatic clear function of A/D data registers
Compare function (window A and window B)
16 ring buffers when the compare function is used