RL78/G13 CHAPTER 12 SERIAL ARRAY UNIT
R01UH0146EJ0100 Rev.1.00 631
Sep 22, 2011
12.5.7 SNOOZE mode function
When SCKp pin input is detected while in the STOP mode, the SNOOZE mode makes data reception that does not
require the CPU possible. Only following CSIs can be specified for asynchronous reception.
• 24 to 64-pin products: CSI00
• 80, 100, 128-pin products: CSI00 and CSI20
When using the SNOOZE mode function, set the SWCm bit of serial standby control register m (SSCm) to 1 before
switching to the STOP mode.
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 12-72. Timing Chart of SNOOZE Mode Operation (once startup) (Type 1: DAPmn = 0, CKPmn = 0)
SSm0
CPU operation status
Normal peration Normal perationSTOP mode
SEm0
SWCm
SSECm
Clock request signal
(internal signal)
L
SDRm0
SCKp pin
SNOOZE mode
SIp pin
INTCSIp
TSFm0
<1> <2> <3> <5> <7>
<6>
<11>
<9>,
<10>
<8>
<4>
STm0
Note 2
Shift register
m0
Data reception (8-bit length) Data reception (8-bit length)
Receive data 2
Receive data 2
Receive data 1
Receive data 1
Read
Note1
Reception & shift operation Reception & shift operation
Notes 1. Only read received data while SWCm = 1 and before the next edge of the SCKp pin input is
detected.
2. The transfer end interrupt (INTCSIp) is cleared either when SWCm is cleared to 0 or when 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, be sure to set the STm0 bit to 1 and clear the SEm0 bit (to stop the operation).
Remarks 1. <1> to <11> in the figure correspond to <1> to <11> in Figure 12-73. Flowchart of SNOOZE Mode
Operation (once startup).
2. 24 to 64-pin products: m = 0; p = 00
80, 100, 128-pin products: m = 0, 1; p = 00, 20
<R>
<R>
To Next Page
Loading...
Need help?
General
