Possible delay with accessing eeproms

Discussion in 'The Projects Forum' started by GeneralH, Feb 21, 2011.

  1. GeneralH

    Thread Starter New Member

    Feb 21, 2011
    I've spent a good deal of time reading over the text books looking for a possible solution but I still need a little help.

    I have a simple project where a microprocessor reads a program from a flash rom or eeprom. I have several chips from the 27c class right to the 39f (3.3v flash). I have the processor on a board with a edge connector that goes to a small board that holds my program chip. When I place the chip on the board and plug it in it works perfectly, everytime.

    As it is now I would program a chip, solder it to the board, plug it in and go. The start to my problem is that I need to test the code and make changes, this requires many erase and reprogram cycles so I went with a dip to ribbon cable that goes from my main board into a breadboard. This also allows me to use any chip I want included the cheaper 39f chips in a TSOP adapter with ease.

    My main problem - take any chip I have from 3.3v to 5v, any package type and solder it down on my board, it works - everytime. Take the same chip and swap it with a ribbon cable to a breadboard then plug the chip into the breadboard and we have issues. I will get the error of no program or the code will reboot over and over at random. Sometimes every second, odd times it will run for a min then reset.

    I've tested and confirmed many times that the ribbon cable to breadboard is wired and making good contact. Power is fine at the selected level based on the chip I am testing. Using a 6 inch ribbon cable I get many resets, with a 18 inch cable I get no program errors. This leads me to think its a delay so from the text books I turned to the 74LS244 which seems to help a little but its still resetting. To help test this I made my own cable using wire that is much thicker then the ribbon cable at 6" and it resets, move it to 3" and it works 50% of the time.

    Is there any login chip other then the 244 I can use to help with this?