UPD72042BGT NEC [NEC], UPD72042BGT Datasheet - Page 4

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

1. PIN FUNCTIONS .............................................................................................................................
2. IEBus OPERATION .........................................................................................................................
3. MICROCOMPUTER INTERFACE .................................................................................................. 22
4. REGISTERS .................................................................................................................................... 29
5. EXAMPLE TIMINGS FOR COMMUNICATION .............................................................................. 59
6. EXAMPLE MICROCOMPUTER PROCESSING FLOW ................................................................ 67
7. ELECTRICAL CHARACTERISTICS .............................................................................................. 82
8. PACKAGE DRAWING ..................................................................................................................... 86
4
1.1
2.1
2.2
2.3
2.4
2.5
3.1
3.2
3.3
3.4
3.5
6.1
6.2
6.3
6.4
PIN FUNCTIONS .....................................................................................................................................
OVERVIEW ..............................................................................................................................................
IEBus COMMUNICATION PROTOCOL ................................................................................................
2.2.1
2.2.2
2.2.3
2.2.4
TRANSMISSION PROTOCOL ...............................................................................................................
TRANSMISSION DATA (CONTENTS OF THE DATA FIELD) ............................................................. 17
BIT FORMAT ........................................................................................................................................... 21
TRANSFER METHOD ............................................................................................................................ 22
DATA TRANSFER FORMAT .................................................................................................................. 23
3.2.1
3.2.2
CONNECTION TO A MICROCOMPUTER ............................................................................................. 27
STANDBY MODE SETTING AND CANCELLATION ............................................................................ 28
RESET MODE SETTING AND CANCELLATION ................................................................................. 28
COMMUNICATION FLAGS .................................................................................................................... 68
MAIN ROUTINE ...................................................................................................................................... 69
INTERRUPT ROUTINE ........................................................................................................................... 70
PROCESSING ROUTINES ..................................................................................................................... 72
6.4.1
6.4.2
6.4.3
6.4.4
6.4.5
6.4.6
6.4.7
Bus Mastership Determination (Arbitration) ............................................................................... 10
Communication Mode ................................................................................................................. 10
Communication Address .............................................................................................................
Broadcast .....................................................................................................................................
Three-Wire Data Transfer (SEL = 1) .......................................................................................... 23
Two-Wire Data Transfer (SEL = 0) ............................................................................................. 25
Communication Flag Initialization Routine ................................................................................. 72
Command Processing Routine ................................................................................................... 73
Master Communication Processing Routine .............................................................................. 73
Slave Data Transmission Processing Routine ........................................................................... 77
Transmission Processing Routine .............................................................................................. 80
Reception Processing Routine ................................................................................................... 81
PD72042B Initial Setting Routine ............................................................................................. 72
Data Sheet S13990EJ3V0DS
CONTENTS
PD72042B
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11
11
6
8
6
8
9