Google

Mar 26, 2008

Troubleshooting a simple 8086 microprocessor based microcomputer

This post will teach you how to troubleshoot a simple microcomputer system such as an SDK-86 board

Identify the Symptoms
make the list of symptoms that you find.they to find wether the proble is with the system or the it is with how the person is use the machine.

Make a careful visual and tactile inspection
check for the components that have been extensively hot.
check to see that all ic are firmly seated in there sockets and that IC's have no bent pins.
check for broken wires and loose connections or a thin film of dust etc.
ome meter check to verify your suspicions.

Check the power supply
determine the power supply voltages for the manual and check the supply voltages directly on the appropriate pins of some IC's to make sure the voltage is actually getting there.

Do a signal Rool Call
make a quick check of some key signals around the CPU of the microprocessor. if the problem is a bad IC this can help point you towards the one that is bad.
check if clock signals is present with the oscilloscope.
check if CPU is putting out control signals such as RD WR and ALE.
check the bus line to see if there is any activity on the buses. if there is no activity on these buses then the common problem is that the CPU is stuck on hold wait halt or reset condition or by afilure od some TTL devices.
perform check on the RAM and ROM and port decoders.

Systematically substitute socketed IC's
the easiest case of substitution is that where you have two identical microprocessor one that works and one that doesn't and the IC's of both units are in the sockets for this case you can use the working system to test the IC's from the non working system.

Troubleshoot soldered in IC's


Equipment for troubleshooting Microcomputers
Logical Analyzers
a logical analyzer is very powerfully troubleshooting tool but to use it effectively you need some detailed knowledge ans d program listing for the system that you are trying to troubleshoot.

for detailed steps for the trouble shooting you can refer the book microprocessor and interfacing by DOUGLAS V HALL . This post is based on that the steps given in that book

You might be also interested in:
:: Assembly Language Programs to compute an expression
:: Interfacing Analog-to-Digital converter to 8086 using 8255
:: Interfacing Digital-To-Analog converter to 8086 using 8255

2 comments:

KOTAPATI.KRISHNAIAH said...

hello sir the best author for 8086 microprocessor.
i am see your's one is troubleshooting is so better. My book
is very bad.



My name is krishna.kotapati
1st year M C A.

INDIA.
A.P

Unknown said...

Hello!!
Can you please tell in which section of the book,microprocessor-Douglas V Hall is this topic written?