Snooze Mode Function (Csi00) - Renesas RL78/G1P Hardware User Manual

RL78/G1P

11.5.7 SNOOZE mode function (CSI00)

SNOOZE mode makes CSI operate reception by SCKp pin input detection while the STOP mode. Normally CSI stops
communication in the STOP mode.
operation by detecting SCKp pin input.
When using the CSI in SNOOZE mode, make the following setting before switching to the STOP mode (see Figure 11-
71 and Figure 11-73 Flowchart of SNOOZE Mode Operation).
• When using the SNOOZE mode function, set the SWCm bit of serial standby control register m (SSCm) to 1 just
before switching to the STOP mode. After the initial setting has been completed, set the SSm1 bit of serial channel
start register m (SSm) to 1.
After a transition to the STOP mode, the CSI starts reception operations upon detection of an edge of the SCKp pin.
Cautions 1. The SNOOZE mode can only be specified when the high-speed on-chip oscillator clock is selected
for f .
CLK
2. The maximum transfer rate when using CSIp in the SNOOZE mode is 1 Mbps.
(1) SNOOZE mode operation (once startup)
Figure 11-70. Timing Chart of SNOOZE Mode Operation (Once Startup) (Type 1: DAPmn = 0, CKPmn = 0)
CPU operation status
SS00
ST00
SE00
SWC0
SSEC0
Clock request signal
(internal signal)
SDR00
SCK00 pin
SI00 pin
Shift register 00
INTCSI00
TSF00
Note Only read received data while SWCm = 1 and before the next edge of the SCKp pin input is detected.
Caution Before switching to the SNOOZE mode or after reception operation in the SNOOZE mode
finishes, set the STm0 bit to 1 (clear the SEm0 bit, and stop the operation).
And after completion the receive operation, also clearing SWCm bit to 0 (SNOOZE mode release).
Remarks 1. <1> to <11> in the figure correspond to <1> to <11> in Figure 11-71 Flowchart of SNOOZE Mode
Operation (Once Startup).
2. m = 0; p = 00
R01UH0895EJ0100 Rev.1.00
Nov 29, 2019
But, using the SNOOZE mode makes reception CSI operate unless the CPU
Normal operation STOP mode
<4>
<3>
<1>
L
Reception & shift operation
<2> <5><6>
CHAPTER 11 SERIAL ARRAY UNIT
SNOOZE mode
<11>
<9>
<10>
Note
<8> Read
Receive data 1
Data reception
<7>
Normal operation
Receive data 2
Receive data 1
Receive data 2
Reception & shift operation
Data reception
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