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CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U13850EJ6V0UD
430
(c) Transfer start
A serial transfer becomes possible when the following two conditions have been satisfied.
• The SIO4 operation control bit (CSIE4) = 1
• After a serial transfer, the internal serial clock is stopped.
Serial transfer starts when the following operation is performed after the above two conditions have been
satisfied.
• Transmit/transmit and receive mode (MODE4 = 0)
Transfer starts when writing to SIO4.
• Receive-only mode
Transfer starts when reading from SIO4.
Caution
After data has been written to SIO4, transfer will not start even if the CSIE4 bit value is
set to 1.
Completion of the final-bit transfer automatically stops the serial transfer operation and sets the interrupt
request flag (INTCSI4).
Figure 10-61. Timing of 3-Wire Variable-Length Serial I/O Mode (When CSIB4 = 08H)
SCK4 (CMODE = 0)
SI4
INTCSI4
1
2
3
4
5
6
7
8
Transfer end
SO4 (DMODE = 0)
LSB
MSB
LSB
MSB
Remark
CSIB4 = 08H (CMODE = 0, DMODE = 0, DIR = 0, BSEL3 to BSEL0 = 1000)