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μ
PD72042A, 72042B
4
DATA SHEET S13990EJ2V0DS00
CONTENTS
1.
PIN FUNCTIONS .............................................................................................................................
1.1
PIN FUNCTIONS.....................................................................................................................................
6
6
2.
IEBus OPERATION.........................................................................................................................
2.1
OVERVIEW..............................................................................................................................................
2.2
IEBus COMMUNICATION PROTOCOL ................................................................................................
2.2.1
Bus Mastership Determination (Arbitration) ...............................................................................
2.2.2
Communication Mode .................................................................................................................
2.2.3
Communication Address .............................................................................................................
2.2.4
Broadcast.....................................................................................................................................
2.3
TRANSMISSION PROTOCOL ...............................................................................................................
2.4
TRANSMISSION DATA (CONTENTS OF THE DATA FIELD) .............................................................
2.5
BIT FORMAT...........................................................................................................................................
8
8
9
10
10
11
11
11
17
21
3.
MICROCOMPUTER INTERFACE .................................................................................................. 22
3.1
TRANSFER METHOD ............................................................................................................................
3.2
DATA TRANSFER FORMAT ..................................................................................................................
3.2.1
Three-Wire Data Transfer (SEL = 1) ..........................................................................................
3.2.2
Two-Wire Data Transfer (SEL = 0) .............................................................................................
3.3
CONNECTION TO A MICROCOMPUTER.............................................................................................
3.4
STANDBY MODE SETTING AND CANCELLATION ............................................................................
3.5
RESET MODE SETTING AND CANCELLATION .................................................................................
22
23
23
26
29
30
30
4.
REGISTERS .................................................................................................................................... 31
5.
EXAMPLE TIMINGS FOR COMMUNICATION.............................................................................. 61
6.
EXAMPLE MICROCOMPUTER PROCESSING FLOW ................................................................ 69
6.1
COMMUNICATION FLAGS ....................................................................................................................
6.2
MAIN ROUTINE ......................................................................................................................................
6.3
INTERRUPT ROUTINE...........................................................................................................................
6.4
PROCESSING ROUTINES.....................................................................................................................
6.4.1
μ
PD72042A or
μ
PD72042B Initial Setting Routine....................................................................
6.4.2
Communication Flag Initialization Routine.................................................................................
6.4.3
Command Processing Routine ...................................................................................................
6.4.4
Master Communication Processing Routine ..............................................................................
6.4.5
Slave Data Transmission Processing Routine ...........................................................................
6.4.6
Transmission Processing Routine ..............................................................................................
6.4.7
Reception Processing Routine ...................................................................................................
70
71
72
74
74
74
75
75
79
82
83
7.
ELECTRICAL CHARACTERISTICS .............................................................................................. 84
8.
PACKAGE DRAWING..................................................................................................................... 88