RL78/G1P
CHAPTER 9 A/D CONVERTER
R01UH0895EJ0100 Rev.1.00
250
Nov 29, 2019
Figure 9-4. Timing Chart When A/D Voltage Comparator Is Used
ADCE
A/D voltage comparator
ADCS
Software
trigger mode
ADCS
Hardware trigger
no-wait mode
ADCS
Hardware trigger
wait mode
Hardware trigger
detection
Conversion
standby
A/D power
supply
stabilization
wait time
Note 2
Conversion
operation
Conversion
standby
Conversion
stopped
Conversion
stopped
Conversion
stopped
Cleared by writing 0
to the ADCS bit.
Hardware trigger
detection
Set by writing 1 to
the ADCS bit.
Conversion
operation
Conversion
standby
Conversion
standby
Trigger
standby
Note 1
Set by writing 1 to
the ADCS bit.
Conversion
standby
Note 1
Conversion
operation
Conversion
standby
A/D voltage comparator: enables operation
Cleared by writing 0 to the ADCS bit or automatically upon
completion of A/D conversion.
Cleared by writing 0 to the ADCS bit or automatically upon
completion of A/D conversion.
Notes 1.
While in the software trigger mode or hardware trigger no-wait mode, the time from the rising of the ADCE
bit to the falling of the ADCS bit must be following time or longer to stabilize the internal circuit.
[Stabilization wait status]
If a high-accuracy channel is selected as the analog input channel:
0.5
s
If a test mode setting (ADTES1 bit of ADTES register = 1) is selected: 0.5
s
If a standard channel is selected as the analog input channel:
2
s
If a temperature sensor output/internal reference voltage output are selected as the analog input channel:
(ADISS bit of ADS register = 1):
2
s
2.
For the second and subsequent conversion in sequential conversion mode and for conversion of the
channel specified by scan 1, 2, and 3 in scan mode, the A/D power supply stabilization wait time do not
occur after a hardware trigger is detected.
Cautions 1. If using the hardware trigger wait mode, setting the ADCS bit to 1 is prohibited (but the bit is
automatically switched to 1 when the hardware trigger signal is detected). However, it is possible
to clear the ADCS bit to 0 to specify the A/D conversion standby status.
2. While in the one-shot conversion mode of the hardware trigger no-wait mode, the ADCS flag is
not automatically cleared to 0 when A/D conversion ends. Instead, 1 is retained.
3. Only rewrite the value of the ADCE bit when ADCS = 0 (while in the conversion
stopped/conversion standby status).
4. To complete A/D conversion, specify at least the following time as the hardware trigger interval:
Hardware
trigger no wait mode: 2 f
CLK
clock + conversion start time + A/D conversion time
Hardware trigger wait mode: 2 f
CLK
clock + Conversion start time + A/D power supply stabilization
wait time + A/D conversion time
Remark
f
CLK
: CPU/peripheral hardware clock frequency
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