UPD75238GJ NEC [NEC], UPD75238GJ Datasheet - Page 110

• Manufacturer Part Number: UPD75238GJ
• Description: 4 BIT SINGLE-CHIP MICROCOMPUTER
• Manufacturer: NEC [NEC]

110
(10) Functions of serial interface (channel 1) registers
Serial clock selection bit (W)
Serial interface operation enable/disable specification bit (W)
CSIM11
CSIE1
Note The values in parentheses are for f
Caution Be sure to write 0 in bits 2 to 6 of the serial operation mode register.
0
0
1
1
(a) Serial operation mode register 1 (CSIM1)
Fig. 4-60 shows the format of serial operation mode register 1 (CSIM1).
CSIM1 is an 8-bit register which specifies a serial interface (channel 1) operation mode and serial
clock.
CSIM1 is manipulated using an 8-bit memory manipulation instruction. Only the high-order one
bit can be manipulated independently. Each bit can be manipulated using its name.
A RESET input clears all bits to 0.
CSIM10
0
1
0
1
0
1
Address
FC8H
Shift operation disabled
Shift operation enabled
External clock applied to SCK1 pin
Not to be set
f
f
X
X
/2
/2
Shift register 1
4
3
(262 kHz or 375 kHz)
(524 kHz or 750 kHz)
Fig. 4-60 Format of Serial Operation Mode Register 1
CSIE1
7
6
0
Serial clock (3-wire serial I/O mode)
Note
Note
Cleared
Count operation
X
Serial clock counter
5
0
= 4.19 MHz or 6.0 MHz.
4
0
3
0
Held
Can be set.
IRQCSI flag
2
0
CSIM11
1
CSIM10
Used only for port 8
Port 8 is shared with
serial function
0
SCK1 pin mode
SO1, SI1 pin
Symbol
CSIM1
Output
Input
PD75238