Sck0/P27 Pin Output Manipulation - NEC mPD780208 Subseries User Manual

13.4.5 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 any value of SCK0 to be set by software (SI0/SB0 and SO0/SB1 pins
to be controlled with bit 0 (RELT) and bit 1 (CMDT) of the serial bus interface control register (SBIC)).
The SCK0/P27 pin output manipulation procedure is described below.
[1] Set 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.
SCK0/P27
CSIM01 and CSIM00 = 1, 0 or 1, 1, respectively
CHAPTER 13 SERIAL INTERFACE CHANNEL 0
Figure 13-33. SCK0/P27 Pin Configuration
To internal
circuit
When CSIE0 = 1
and
User's Manual U11302EJ4V0UM
Set with a bit
manipulation instruction
P27 output
latch
SCK0
(set to 1 while transfer
is stopped)
From serial clock
controller
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