Bit Format - NEC V850/SB1 User Manual

(c) Lock setting conditions
Control Data
Note
3H, 6H
AH, BH
0H, 4H, 5H, EH, FH
(d) Unlock release conditions (while locked)
Control Data
Note
3H, 6H
AH, BH
0H, 4H, 5H, EH, FH
Note The frame end of control data 6H (slave status read/unlock) occurs when the parity in the data field is odd,
and when the acknowledge signal from the IEBus unit is repeated up to the maximum number of transfer
bytes without being output.

19.1.8 Bit format

The format of the bits constituting the communication frame of the IEBus is shown below.
Logic "1"
Logic "0"
Preparation period:
Synchronization period: Next high-level (logic "0") period
Data period:
Stop period:
The synchronization period and data period are almost equal to each other in length.
The IEBus synchronizes each bit. The specifications on the time of the entire bit and the time related to the period
allocated to that bit differ depending on the type of the transmit bit, or whether the unit is the master unit or a slave
unit.
The master and slave units monitor whether each period (preparation period, synchronization period, data period,
and stop period) is output for specified time while they are in communication. If a period is not output for the specified
time, the master and slave units report a timing error, immediately terminate communication and enter the standby
status.
CHAPTER 19 IEBus CONTROLLER (V850/SB2)
Broadcasting Communication
Communication End
Cannot be locked Cannot be locked
Cannot be locked Cannot be locked
Broadcasting Communication from
Lock Request Unit
Communication End
Unlocked Unlocked
Remains locked Remains locked
Figure 19-9. Bit Format of IEBus
Preparation Synchronization
period period
First low-level (logic "1") period
Period indicating value of bit
Last low-level (logic "1") period
User's Manual U13850EJ6V0UD
Frame End Communication End
Cannot be locked
Cannot be locked
Cannot be locked
Individual Communication from
Frame End Communication End
Unlocked
Unlocked
Remains locked
Data period
Individual Communication
Frame End
Lock set
Lock set
Cannot be locked
Lock Request Unit
Frame End
Remains locked
Remains locked
Remains locked
Stop period
557