UPD72042BGT NEC [NEC], UPD72042BGT Datasheet - Page 23

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

3.2 DATA TRANSFER FORMAT
3.2.1 Three-Wire Data Transfer (SEL = 1)
(1) Control mode
RESET
I
O : Output state
O* : State in which 1 is output
Remark After reset (RESET) cancellation, the state enabling writing to the register at address 0000B is set.
Caution In control mode, each data item is read every eighth clock pulse. (Data of less than eight clock
When the C/D input is set high, control mode is set to control data transfer. Data transfer control involves the
following processing.
0
1
1
1
2
: Input state
Register address setting
Register read/write selection
periods is ignored.)
CS
1
0
SCK
C/D
SEL
SI
1
0
Table 3-1 I/O States of the SIO (SI) and SO Pins
C/D
1
0
1
0
SI (SIO)
Data Sheet S13990EJ3V0DS
O
I
I
I
I
Hi-Z : High-impedance state
W
R
/
Hi-Z
Hi-Z
Hi-Z
SO
O*
O
: Don’t care
A0
A1
Three-wire/two-wire
Three-wire
A2
Two-wire
–
–
A3
Reset state
Chip nonselected state
Control mode
Data write mode
Data read mode
Control mode
Data write mode
Data read mode
State
Operating mode
PD72042B
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