UPD75238GJ NEC [NEC], UPD75238GJ Datasheet - Page 103

• 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. 4-55 Command Transfer Operation from Master Device to Slave Device
Set
CMDT
Set
CMDD
Write
to SIO0
1
C7
2
C6
3
C5
Serial receive operation
Serial send operation
Command
4
C4
5
C3
6
C2
7
C1
8
C0
9
Generate
IRQCSI0
Generate
IRQCSI0
Read
SIO0
Interrupt handling (preparation for next serial transfer)
Analyze
command
Set
ACKT
Output
ACK
Output
BUSY
ACK
Set
ACKD
BUSY
Clear
BUSY
Clear
BUSY
READY
Stop
SCK0