NEC uPD78056Y - Manual (Page 429)

429
CHAPTER 18 SERIAL INTERFACE CHANNEL 1
(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.
During restart of transmission/reception, remaining data can be transferred by setting CSIE1 to 1 and
writing any data to the serial I/O shift register 1 (SIO1).
Cautions 1. If the HALT instruction is executed during automatic transmission/reception, transfer
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
Remark CSIE1 : Bit 7 of serial operating mode register 1 (CSIM1)
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)