Well i recently received a project to do , and it is basicly a IC tester. Now it is required we use a micro controller and our design must involve serial comms to a computer. The micro and serial comms i can handle the part i am currently struggling with is how the user must type in the IC number of the chip he/she wants to test. Now the plan i am going with is to interface a 12 Button keypad with my micro and a LCD display. If the user press "7" then a 7 must appear on the LCD , then after the user has enter a 4 digit IC number, then the user must press hash(Act as enter) and then the micro will do its stuff. now my question to you guys and the few girls that is on this forums , is the plan i am going with possible.

 

I would not get too bogged down on the trivial things, like entering the type number of the logic IC. You need to think about how many logic families are going to be tested, and how you will apply signals to the inputs and monitor the outputs to adequately test all the functions.

Produce a schematic of the tester and a means of storing the input/output pin functions of each logic IC so the external switching will take place automatically with the entry of the IC type number.

 

The logic families i am going to test is fairly basic ones. 7408 - Quad 2 Input AND GATES, 7432 - Quad 2 input Or gate, 7404 - Inverters,ect, i have a plan on how i am going to test the individual IC's. I will post tomorow a basic diagram of what i am planning to do, but my main concern is the LCD and Keypad because i need to know if the Keypad sends a Binary/hex value from its output pins and if the LCD accepts Hex/Binary on its input pins before i can start coding my Micro Controller, the micro controller i will be using is a Atmel 8052 and i will be using a MAX232 to connect to the computer.

 

I would put more of the burden on the computer, and let it take the input from the user and verify it: what if someone enters 5404 instead of 7404? How can they correct an input error? Will you accept any of the 74xxx variations such as 74LSxx, 74HCxx, 74Cxx, 74ALSxx, etc?

Once the computer verified that an entered part number is valid, I would download some type of map to the test unit, something like "'7400 NAND' IIOIIOGOIIOII5". '7400 NAND' is eye-candy -- something to display on the LCD. The Is & Os tell the tester the Inputs from the Outputs, along with G(round) and Vcc. Or, you may want to download an entire test pattern, such as I1LI2LO3H... indicating which pins to drive High or Low, and where to expect the output and its value.

--Rich

 

Ye i was thnking abt how am i gna distinguish between the ic that may be faulty and between the user entering the inc0rect ic number fr the ic he/she wana test,where cn i download a test pattern fr a certain ic and how doer that test pattern actualy work?

 

Each logic IC will have a data sheet that completely describes the proper functioning of that logic. If you understand the logic, then you can test it.

How are you planning on changing the test fixture to accommodate the different IC's?

 

I will read the characters in and compare them to the different ic families ,so i wil use a register in the micro fr each ic im g0ing to test.

 

you have a nice project out there.. it quite amazing.. but it think if your tester is handy.. you will hav a nice feeling if its not connected in a computer for the portability's sake.. i got some idea on it but it wont be easy.. and it may cost a lot.. but you still have a great idea! i wish i have that!hehe..

 

for guzmas,

its nothing men.. coz its hard..realy hard.. im still reserching for it.. im not gonna keep it a secret for a while until i know how.. Just continue what were you doing.. and dont use lcd any more coz you should use the monitor intsead.. and use the keyboard of the computer instead.. by d way.. why dont you post your schematic of it..?

my browser is always having an error, and i dont know if my pm for gusmas really send..

 

Ok guys i got a problem! I am using a 3X4 keypad. The keypad encoder i have is fr a 4X4 keypad. Any id
Eas?

 

Will the encoder not work for the 3 X 4 keypad?

 

It works with only certain numbers, is it possible to send inputs through port1,2 and 3 to the microcontroller, i am using the atmel 8052