UPD75238GJ NEC [NEC], UPD75238GJ Datasheet - Page 86

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

86
(b) Serial bus interface control register (SBIC)
Fig. 4-41 shows the format of the serial bus interface control register (SBIC).
SBIC is an 8-bit register consisting of bits for controlling the serial bus and flags for indicating the
states of input data from the serial bus. SBIC is used mainly in the SBI mode.
SBIC is manipulated using a bit manipulation instruction. SBIC cannot be manipulated using a 4-bit
or 8-bit memory manipulation instruction.
Each bit may or may not allow read and/or write operation. (See Fig. 4-41.)
A RESET input clears all bits to 0.
Caution Only the following bits can be used in the three-wire and two-wire serial I/O modes:
Remarks 1. (R)
Address
FE2H
• Bus release trigger bit (RELT): Sets the SO0 latch.
• Command trigger bit (CMDT): Clears the SO0 latch.
2. (W) : Write only
3. (R/W): Read/write
Fig. 4-41 Format of Serial Bus Interface Control Register (SBIC) (1/3)
BSYE
7
Busy enable bit (R/ W)
ACKD
: Read only
6
Acknowledge detection flag (R)
ACKE
5
Acknowledge enable bit (R/ W)
ACKT
4
Acknowledge trigger bit (W)
CMDD
3
Command detection flag (R)
RELD
2
Bus release detection flag (R)
CMDT
1
Command trigger bit (W)
RELT
0
Bus release trigger bit (W)
Symbol
SBIC
PD75238