UPD75518 NEC, UPD75518 Datasheet - Page 114

• Manufacturer Part Number: UPD75518
• Description: 4 BIT SINGLE-CHIP MICROCOMPUTER
• Manufacturer: NEC

114
4.9.3 Register Functions
(1) Serial operation mode register 1 (CSIM1)
Serial clock selection bit (W)
Serial interface operation enable/disable specification bit (W)
CSIM11
CSIE1
Fig. 4-55 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.
When the RESET signal is input, this register is set to 00H.
Remark (W): Write only
Note The values at 4.19 MHz and 6.0 MHz are indicated in parentheses.
Caution Be sure to write 0 in bits 2 to 6 of the serial operation mode register 1 (CSIM1).
0
0
1
1
Address
FC8H
CSIM10
0
1
0
1
0
1
CSIE1
7
Shift operation disabled
Shift operation enabled
Shift register operation
External clock applied to SCK1 pin
Not to be set
f
f
X
X
Fig. 4-55 Format of Serial Operation Mode Register 1 (CSIM1)
/2
/2
4
3
(262 kHz or 375 kHz)
(524 kHz or 750 kHz)
6
0
5
0
Serial clock (3-wire serial I/O mode)
4
0
Note
Note
Cleared
Count operation
Serial clock counter
Serial interface operation enable/disable specification bit (W)
3
0
2
0
CSIM11
Held
Can be set.
1
EOT flag
CSIM10
0
Serial clock selection bit (W)
Symbol
CSIM1
Used only for port 8
Used in serial interface as
well as for port 8
SO1, SI1 pin
SCK1 pin mode
Output
Input
PD75518(A)