UPD75238GJ NEC [NEC], UPD75238GJ Datasheet - Page 105

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

Master device processing (receiver)
Transfer line
Slave device processing (transmitter)
Program processing
Program processing
Hardware operation
Hardware operation
SCK0 pin
SB0 pin
BUSY
Write
to SIO0
Clear
BUSY
READY
Fig. 4-57 Data Transfer Operation from Master Device to Slave Device
Stop
SCK0
Write FFH
to SIO0
1
D7
2
D6
3
Serial receive operation
D5
Serial send operation
4
D4
Data
5
D3
6
D2
7
D1
8
D0
9
Generate
Generate
IRQCSI0
IRQCSI0
Read
SIO0
Output
ACK
Set
ACKT
ACK
Write FFH
to SIO0
Set
ACKD
BUSY
Output
BUSY
Receive data processing
Write
to SIO0
Clear
BUSY
READY
1
Serial reception
D7
2
D6