NEC uPD78P078 - Manual (Page 363)

363
CHAPTER 17 SERIAL INTERFACE CHANNEL 0 (
µ
PD78078 SUBSERIES)
To Internal
Circuit
SCK0/P27 P27 Output
Latch
When CSIE0 = 1
and
CSIM01 and CSIM00 are 1 and 0, or 1 and 1.
Set by bit manipulation
instruction
SCK0 (1 when transfer stops)
From Serial Clock
Control Circuit
17.4.5 SCK0/P27 pin output manipulation
Because the SCK0/P27 pin incorporates an output latch, static output is also possible by software in addition
to normal serial clock output.
P27 output latch manipulation enables setting any value to SCK0 by software (SI0/SB0 and SO0/SB1 pin to be
controlled with the RELT and CMDT bits of the serial bus interface control register (SBIC)).
SCK0/P27 pin output manipulating procedure is described below.
(1) Set the serial operating mode register 0 (CSIM0) (SCK0 pin enabled for serial operation in the output mode).
SCK0 = 1 with serial transfer suspended.
(2) Manipulate the P27 output latch with a bit manipulation instruction.
Figure 17-34. SCK0/P27 Pin Configuration