RL78/G1P
CHAPTER 11 SERIAL ARRAY UNIT
R01UH0895EJ0100 Rev.1.00
332
Nov 29, 2019
11.3.14 Serial standby control register m (SSCm)
The SSC0 register is used to control the startup of reception (the SNOOZE mode) while in the STOP mode when
receiving CSI00 or UART0 serial data.
The SSCm register can be set by a 16-bit memory manipulation instruction.
The lower 8 bits of the SSCm register can be set with an 8-bit memory manipulation instruction with SSCmL.
Reset signal generation clears the SSCm register to 0000H.
Caution The maximum transfer rate in the SNOOZE mode is as follows.
When using CSI00: Up to 1 Mbps
When using UART0: 4800 bps only
Figure 11-17. Format of Serial Standby Control Register m (SSCm)
Address: F0138H After reset: 0000H R/W
Symbol 15
14
13
12
11
10 9 8 7 6 5 4 3 2 1 0
SSCm 0 0 0 0 0 0 0 0 0 0 0 0 0 0 SS
ECm
SWC
m
SSECm
Selection of whether to enable or disable the generation of
communication error interrupts in the SNOOZE mode
0
Enable the generation of error interrupts (INTSRE0)
1
Disable the generation of error interrupts (INTSRE0)
The SSECm bit can be set to 1 or 0 only when both the SWCm and EOCmn bits are set to 1 during UART
reception in the SNOOZE mode. In other cases, clear the SSECm bit to 0.
Setting SSECm, SWCm = 1, 0 is prohibited.
SWCm
Setting of the SNOOZE mode
0
Do not use the SNOOZE mode function.
1
Use the SNOOZE mode function.
When there is a hardware trigger signal in the STOP mode, the STOP mode is exited, and A/D conversion is
performed without operating the CPU (the SNOOZE mode).
The SNOOZE mode function can only be specified when the high-speed on-chip oscillator clock is selected for
the CPU/peripheral hardware clock (f
CLK
). If any other clock is selected, specifying this mode is prohibited.
Even when using SNOOZE mode, be sure to set the SWCm bit to 0 in normal operation mode and change it to 1
just before shifting to STOP mode.
Also, be sure to change the SWCm bit to 0 after returning from STOP mode to normal operation mode.
Caution Setting SSECm, SWCm = 1, 0 is prohibited.
Figure 11-18. Interrupt in UART Reception Operation in SNOOZE Mode
EOCmn Bit
SSECm Bit
Reception Ended Successfully
Reception Ended in an Error
0
0
INTSRx is generated.
INTSRx is generated.
0
1
INTSRx is generated.
INTSRx is generated.
1
0
INTSRx is generated.
INTSRx is generated.
1
1
INTSRx is generated.
No interrupt is generated.