NEC PD750008 User Manual
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µPD750008 USER'S MANUAL
Figure 5-40. Format of Serial Operation Mode Register (CSIM) (4/4)
Remarks 2. The P01/SCK pin assumes any of the following states according to the state of
CSIE, CSIM1, and CSIM0:
CSIE
CSIM1
CSIM0
P01/SCK pin state
0
0
0
Input port
1
0
0
High impedance
0
0
1
High level output
0
1
0
0
1
1
1
0
1
Serial clock output (High level output)
1
1
0
1
1
1
3. When clearing CSIE during serial transfer, use the following procedure:
<1> Disable interrupts by clearing the interrupt enable flag (IECSI).
<2> Clear CSIE.
<3> Clear the interrupt request flag (IRQCSI).
Examples 1. f
X
/2
4
is selected as the serial clock, serial interrupt IRQCSI, is generated each
time serial transfer is completed, and serial transfer is performed in the SBI
mode with the SB0 pin used as the serial data bus.
SEL
MB15
; or CLR1 MBE
MOV
XA,#10001010B
MOV
CSIM,XA
; CSIM <– 10001010B
2. Serial transfer dependent on the contents of CSIM is enabled.
SEL
MB15
; or CLR1 MBE
SET1
CSIE