Basic Transmit Mode Operation Timing - NEC PD789488 User Manual

(b) Basic transmit mode
In this mode, the specified number of 8-bit unit data are transmitted.
Serial transfer is started when any data is written to serial I/O shift register 1A0 (SIO1A0) while bit 7
(CSIE10) of serial operation mode register 1A0 (CSIM1A0) is set to 1, and bit 7 (RE0) of automatic data
transmit/receive control register 0 (ADTC0) is set to 0.
Upon completion of transmission of the last byte, the interrupt request flag (CSIIF10) is set.
termination of automatic transmission/reception should be checked by using bit 3 (TRF0) of automatic
data transmit/receive control register 0 (ADTC0), not by CSIIF10.
If a receive operation is not executed, the P25/SI10 pin can be use as normal I/O port.
Figure 12-10 shows the basic transmit mode operation timing, and Figure 12-11 shows the operation
flowchart.
Figure 12-12 shows buffer RAM operation when repeatedly transmitting 6 bytes.
SCK10
SO10 D7 D6 D5 D4 D3 D2 D1 D0
CSIIF10
TRF0
Cautions 1. Because, in the basic transmit mode, the automatic transmit/receive function reads
2. When TRF0 is cleared, the SO10 pin becomes low level.
Remark CSIIF10:
TRF0:
240
CHAPTER 12 SERIAL INTERFACE 1A0
Figure 12-10. Basic Transmit Mode Operation Timing
Interval
data from the buffer RAM after 1-byte transmission, an interval is inserted until the
next transmission. As the buffer RAM read is performed at the same time as CPU
processing, the maximum interval is dependent upon CPU processing and the
value of automatic data transmit/receive interval specification register 0 (ADTI0)
(refer to 12.4.3 (5) Interval time of automatic transmission/reception).
Interrupt request flag
Bit 3 of automatic data transmit/receive control register 0 (ADTC0)
User's Manual U15331EJ4V1UD
D7 D6 D5 D4 D3 D2 D1 D0
The