UPD784938 Datasheet, PDF (479/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 20 IEBus CONTROLLER
20.1.8 Bit format
Figure 20-9 shows the format of the bits constituting the communication frame of the IEBus.
Figure 20-9. Bit Format of IEBus
Logic “1”
Logic “0”
Preparation Synchronization Data period Stop period
period
period
Preparation period:
First low-level (logic “1”) period
Synchronization period: Next high-level (logic “0”) period
Data period:
Period indicating value of bit
Stop period:
Last low-level (logic “1”) period
The synchronization period and data period are almost equal to each other in length.
The IEBus synchronizes each 1 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.
Preliminary User’s Manual U13987EJ1V0UM00
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