UPD75238GJ NEC [NEC], UPD75238GJ Datasheet - Page 104

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

Master device processing (transmitter)
Transfer line
Slave device processing (receiver)
Program processing
Program processing
Hardware operation
Hardware operation
SCK0 pin
SB0 pin
Fig. 4-56 Data Transfer Operation from Master Device to Slave Device
Write
to SIO0
1
D7
2
D6
3
D5
Serial receive operation
Serial send operation
4
D4
Data
5
D3
6
D2
7
D1
8
D0
9
Generate
IRQCSI0
Generate
IRQCSI0
Read
SIO0
Interrupt handling (preparation for next serial transfer)
Set
ACKT
Output
ACK
Output
BUSY
ACK
Set
ACKD
BUSY
Clear
BUSY
Clear
BUSY
READY
Stop
SCK0