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CHAPTER 18 SERIAL INTERFACE CHANNEL 1
SCK1
SO1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
SI1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
Restart Command
CSIE1 = 1, Write to SIO1
Suspend
CSIE1 = 0 (Suspended Command)
(d) Automatic transmission/reception suspending and restart
Automatic transmission/reception can be temporarily suspended by setting bit 7 (CSIE1) of the serial
operating mode register 1 (CSIM1) to 0.
If during 8-bit data transfer, the transmission/reception is not suspended if bit 7 (CSIE1) is set to 0. It
is suspended upon completion of 8-bit data transfer.
When suspended, bit 3 (TRF) of the automatic data transmit/receive control register (ADTC) is set to 0
after transfer of the 8th bit, and all the port pins used with the serial interface pins for dual function (P20/
SI1, P21/SO1, P22/SCK1, P23/STB and P24/BUSY) are set to the port mode.
To restart auto send and receive, set CSIE1 at 1 and write the desired value in serial I/O shift register
1 (SIO1). The remaining can be transmitted in this way.
Cautions 1. If the HALT instruction is executed during automatic transmission/reception, trans-
fer is suspended and the HALT mode is set if during 8-bit data transfer. When the
HALT mode is cleared, automatic transmission/reception is restarted from the
suspended point.
2. When suspending automatic transmission/reception, do not change the operating
mode to 3-wire serial I/O mode while TRF=1.
Figure 18-17. Automatic Transmission/Reception Suspension and Restart
CSIE1: Bit 7 of serial operation mode register 1 (CSIM1)