NEC PD78F9488 User Manual
Page 227
CHAPTER 12 SERIAL INTERFACE 1A0
User’s Manual U15331EJ4V1UD
227
(2) Communication
operation
In 3-wire serial I/O mode, data transmission/reception is performed in 8-bit units. Data is
transmitted/received bit by bit in synchronization with the serial clock.
Serial I/O shift register 1A0 (SIO1A0) shift operations are performed in synchronization with the fall of the
serial clock (SCK10). Then transmit data is held in the SO10 latch and output from the SO10 pin. Also,
receive data input to the SI10 pin is latched in the SIO1A0 on the rise of SCK10.
At the end of an 8-bit transfer, the operation of SIO1A0 stops automatically, and the interrupt request signal
(INTCSI10) is generated.
Figure 12-5. 3-Wire Serial I/O Mode Timing (1/2)
(i) Master operation timing
1
2
3
4
5
6
7
8
DO7
DO6
DO5
DO4
DO3
DO2
DO1
DO0
DI7
DI6
DI5
DI4
DI3
DI2
DI1
DI0
SCK10
SO10
Note
SI10
SIO1A0
write
INTCSI10
Note The value of the last bit previously output is output.