DATA SHEET
MOS INTEGRATED CIRCUIT
µ
PD72042
LSI DEVICES FOR Inter Equipment Bus
TM
(IEBus
TM
)
PROTOCOL CONTROL
The
µ
PD72042 is a microcomputer peripheral LSI device for IEBus protocol control.
The
µ
PD72042 performs all the processing required for layers 1 and 2 of the IEBus. The devices incorporate large
transmission and reception buffers, allowing the microcomputer to perform IEBus operations without interruption.
They also contain an IEBus driver and receiver, allowing them to directly connected to the bus directly.
FEATURES
•
Control of layers 1 and 2 of the IEBus protocol
• Support of a multi-master scheme
• Broadcast function
• Two communication modes having different
transmission speeds can be selected.
•
Microcomputer interface
Three-/two-wire serial I/O,
Transfer starting with MSB
•
Program crashes can be detected by means of a
watchdog timer.
•
Low power consumption (standby mode):
Transmission speed
Mode 0
Mode 1
q
q
50
µ
A (max)
•
Oscillator frequency (f ):
X
6 MHz
Approx. 3.9 Kbps
Approx. 17 Kbps
• frequency accuracy:
±1.5%
5 V
±10%
•
Operating voltage:
Built-in IEBus driver and receiver
Transmission and reception buffers
Transmission buffer
Reception buffer
: 33 bytes, FIFO
: 40 bytes, FIFO (capable of
holding more than one frame
of reception data.)
ORDERING INFORMATION
Part number
Package
16-pin plastic SOP (9.53 mm (375))
µ
PD72042GT
The information in this document is subject to change without notice. Before using this document, please
confirm that this is the latest version.
Not all devices/types available in every country. Please check with local NEC representative for availability
and additional information.
Document No. S14870EJ1V0DS00 (1st edition)
Date Published June 2000 N CP(N)
Printed in Japan
©
2000
µ
PD72042
CONTENTS
1. PIN FUNCTIONS ............................................................................................................................
1.1
PIN FUNCTIONS ...................................................................................................................................
6
6
2. IEBus OPERATION .......................................................................................................................
2.1
2.2
OVERVIEW ..............................................................................................................................................
IEBus COMMUNICATION PROTOCOL ..............................................................................................
2.2.1
2.2.2
2.2.3
2.2.4
2.3
2.4
2.5
Bus Mastership Determination (Arbitration) ...............................................................................
Communication Mode .................................................................................................................
Communication Address .............................................................................................................
Broadcast .....................................................................................................................................
8
8
9
10
10
11
11
11
17
21
TRANSMISSION PROTOCOL ..............................................................................................................
TRANSMISSION DATA (CONTENTS OF THE DATA FIELD) ........................................................
BIT FORMAT ..........................................................................................................................................
3. MICROCOMPUTER INTERFACE ................................................................................................. 22
3.1
3.2
TRANSFER METHOD ...........................................................................................................................
DATA TRANSFER FORMAT ................................................................................................................
3.2.1
3.2.2
3.3
3.4
3.5
Three-Wire Data Transfer (SEL = 1) ..........................................................................................
Two-Wire Data Transfer (SEL = 0) .............................................................................................
22
23
23
25
27
28
28
CONNECTION TO A MICROCOMPUTER .........................................................................................
STANDBY MODE SETTING AND CANCELLATION .......................................................................
RESET MODE SETTING AND CANCELLATION ............................................................................
4. REGISTERS .................................................................................................................................... 29
5. EXAMPLE TIMINGS FOR COMMUNICATION .......................................................................... 59
6. EXAMPLE MICROCOMPUTER PROCESSING FLOW ............................................................. 67
6.1
6.2
6.3
6.4
COMMUNICATION FLAGS ...................................................................................................................
MAIN ROUTINE .....................................................................................................................................
INTERRUPT ROUTINE .........................................................................................................................
PROCESSING ROUTINES ....................................................................................................................
6.4.1
6.4.2
6.4.3
6.4.4
6.4.5
6.4.6
6.4.7
Communication Flag Initialization Routine .................................................................................
Command Processing Routine ...................................................................................................
Master Communication Processing Routine ..............................................................................
Slave Data Transmission Processing Routine ...........................................................................
Transmission Processing Routine ..............................................................................................
Reception Processing Routine ...................................................................................................
68
69
70
72
72
73
73
77
80
81
µ
PD72042 Initial Setting Routine ............................................................................................... 72
7. ELECTRICAL CHARACTERISTICS ............................................................................................. 82
8. PACKAGE DRAWING .................................................................................................................... 86
4
Data Sheet S14870EJ1V0DS00
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