Renesas RL78 Series User Manual page 378

RL78/G1D
12.8 SNOOZE Mode Function
In the SNOOZE mode, A/D conversion is triggered by inputting a hardware trigger in the STOP mode. Normally, A/D
conversion is stopped while in the STOP mode, but, by using the SNOOZE mode, A/D conversion can be performed
without operating the CPU by inputting a hardware trigger. This is effective for reducing the operating current.
If the A/D conversion result range is specified using the ADUL and ADLL registers, A/D conversion results can be
judged at a certain interval of time in SNOOZE mode. Using this function enables power supply voltage monitoring and
input key judgment based on A/D inputs.
In the SNOOZE mode, only the following two conversion modes can be used:
● Hardware trigger wait mode (select mode, one-shot conversion mode)
● Hardware trigger wait mode (scan mode, one-shot conversion mode)
Caution That the SNOOZE mode can only be specified when the high-speed on-chip oscillator clock is
selected for f
Real-time clock (RTC),
12-bit interval timer
A/D conversion end
interrupt request
signal Note 1 (INTAD)
When using the SNOOZE mode function, the initial setting of each register is specified before switching to the STOP
mode (for details about these settings, see 12.7.3 Setting up hardware trigger wait mode
STOP mode, bit 2 (AWC) of A/D converter mode register 2 (ADM2) is set to 1. After the initial settings are specified, bit 0
(ADCE) of A/D converter mode register 0 (ADM0) is set to 1.
If a hardware trigger is input after switching to the STOP mode, the high-speed on-chip oscillator clock is supplied to
the A/D converter. After supplying this clock, the system automatically counts up to the A/D power supply stabilization
wait time, and then A/D conversion starts.
The SNOOZE mode operation after A/D conversion ends differs depending on whether an interrupt signal is
Note 1
generated .
Notes 1. Depending on the setting of the A/D conversion result comparison function (ADRCK bit, ADUL/ADLL
register), there is a possibility of no interrupt signal being generated.
2. Be sure to set the ADM1 register to E2H or E3H.
Remark The hardware trigger is INTRTC or INTIT.
Specify the hardware trigger by using the A/D Converter Mode Register 1 (ADM1).
R01UH0515EJ0120 Rev.1.20
Dec 16, 2016
.
CLK
Figure 12-34. Block Diagram When Using SNOOZE Mode Function
Hardware trigger
input
Clock request signal
(internal signal)
A/D converter
High-speed on-chip
oscillator clock
CHAPTER 12 A/D CONVERTER
Clock generator
Note 2
). Just before move to
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