UPD72042BGT NEC [NEC], UPD72042BGT Datasheet - Page 37

• Manufacturer Part Number: UPD72042BGT
• Description: LSI DEVICE FOR Inter Equipment Bus (IEBus) PROTOCOL CONTROL
• Manufacturer: NEC [NEC]

[Control bits]
• Contents of control bits
Notes 1. The value of bit 3 (MSB) determines the transfer direction of the subsequent data-length field data and
This control field is used to set the control bits (four bits).
AH
BH
CH
DH
EH
FH
0H
1H
2H
3H
4H
5H
6H
7H
8H
9H
2. 3H, 6H, AH, and BH are control bits used for lock setting and cancellation.
data field data.
When bit 3 is set to 1: Data is transferred from the master unit to a slave unit.
When bit 3 is set to 0: Data is transferred from a slave unit to the master unit.
When an undefined value of 1H, 2H, 8H, 9H, CH, or DH is sent, no acknowledgement is returned.
Bit 3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Note 1
Bit 2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Data Sheet S13990EJ3V0DS
Bit 1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
Bit 0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Slave status (SSR) read
Undefined
Undefined
Data read and lock
Lock address read (low-order 8 bits)
Lock address read (high-order 4 bits)
Slave status (SSR) read and unlock
Data read
Undefined
Undefined
Command write and lock
Data write and lock
Undefined
Undefined
Command write
Data write
Function
Note 2
PD72042B
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