UPD784938 Datasheet, PDF (472/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 20 IEBus CONTROLLER
Table 20-2. Contents of Control Bits
Bit 3^{Note 1}
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Bit 2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
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
Function
Reads slave status
Undefined
Undefined
Reads data and locks^{Note 2}
Reads lock address (low-order 8 bits)^{Note 3}
Reads lock address (high-order 4 bits)^{Note 3}
Reads slave status and unlocks^{Note 2}
Reads data
Undefined
Undefined
Writes command and locks^{Note 2}
Writes data and locks^{Note 2}
Undefined
Undefined
Writes command
Writes data
Notes 1. The telegraph length bit of the telegraph length field and data transfer direction of the data field change as
follows depending on the value of bit 3 (MSB).
If bit 3 is ‘1’: Transfer from master unit to slave unit
If bit 3 is ‘0’: Transfer from slave unit to master unit
2. This is a control bit that specifies locking or unlocking (refer to 20.1.7 (4) Locking and unlocking).
3. The lock address is transmitted in 1-byte (8-bit) units and is configured as follows:
MSB
LSB
Control bit: 4H
Low-order 8 bits
Control bit: 5H
Undefined
High-order 4 bits
If the control bit received from the master unit is not as shown in Table 20-3, the unit locked by the master
unit rejects accepting the control bit, and does not output the acknowledge bit.
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Preliminary User’s Manual U13987EJ1V0UM00