Digital488 User’s Manual
916895
Service Information, 5-1
Service Information
5
Factory Service
IOtech maintains a factory service center in Cleveland, Ohio. If problems are encountered in using the
Digital488 you should first telephone the factory. Many problems can be resolved by discussing the
problems with our applications department. If the problem cannot be solved by this method, you will be
instructed as to the proper return procedure.
Theory of Operation
The Heart of the
Digital488
is a 6809 microprocessor [U101] supported by 8K bytes of firmware EPROM
[U102 (2764)] and 8K bytes of static RAM [U103 (6264)]. A Versatile Interface Adapter [U104 (65B22)]
is used to generate real-time interrupts for the firmware operating system. The front panel annunciators are
also driven by U104 through an inverter [U113 (74LS04)].
The IEEE 488 bus interface is accomplished by a TMS9914A [U106] controller with drivers U107 and
U108. The digital I/O ports are controlled by 'PIA's [U202-U204 (68B21)]. SW1 is read through one port
of U204.
Power is supplied by an external unregulated 9 volt wall mount supply. Regulation to the re5 volts
is provided by U109 [7805]. Decoding of the microprocessor address space is accomplished with a
Programmable Logic Array [U110 (16L8)]. The Memory space allocation is...
Address
Device
Part Number
Function
$6000-$7FFF U103
6264 Static
RAM
$9200-$9204 U202 6821
Digital
I/O
$9400-$9404 U203 6821
Digital
I/O
$9800-$9804 U204 6821
Digital
I/O
$A000-$A007 U106
TMS9914A IEEE
Controller
$B000-$B00F U104
R65C22
VIA
$E000-$FFFF U102
2764
Programmed
EPROM
Содержание Digital488
Страница 21: ...2 10 Getting Started 11 19 01 Digital488 User s Manual...
Страница 37: ...3 16 Command Descriptions 7 17 01 Digital488 User s Manual...
Страница 45: ...Digital488 Mother Board Component Layout 5 2 Service Information 916895 Digital488 User s Manual...
Страница 48: ...Digital488 32 OEM Component Layout Digital488 User s Manual 916895 Service Information 5 5...
Страница 49: ...Digital488 OEM Component Layout 5 6 Service Information 916895 Digital488 User s Manual...
Страница 51: ...5 8 Service Information 916895 Digital488 User s Manual...
Страница 61: ...B 8 Notes...
Страница 62: ...Appendix C Digital488 OEM Mechanical Dimensions Board Dimensions C 1...
Страница 63: ...IEEE Connector Mounting and Hole Punch Out C 2...