NEC UPD789426 Series User Manual page 245

(iv) Master operation (when DAP20 = 0, CKP20 = 1, SSE20 = 0)
SIO20
write
SCK20
SO20
SI20
INTCSI20
(v) Slave operation (when DAP20 = 0, CKP20 = 1, SSE20 = 0)
SIO20
write
SCK20
Note
SIO20 write (master)
SI20
SO20
INTCSI20
Note The data of SI20 is loaded at the first rising edge of SCK20. Make sure that the master outputs the
first bit before the first rising of SCK20.
246
CHAPTER 12 SERIAL INTERFACE 20
Figure 12-11. 3-Wire Serial I/O Mode Timing (3/7)
1 2 3
DO7 DO6 DO5
DI7 DI6 DI5
1 2 3
DI7 DI6 DI5
DO7 DO6 DO5
User's Manual U15075EJ2V1UD
4 5 6
DO4 DO3 DO2
DI4 DI3 DI2
4 5 6
DI4 DI3 DI2
DO4 DO3 DO2
7 8
DO1 DO0
DI1 DI0
7 8
DI1 DI0
DO1 DO0