EEPROM Failure? Wierd Problem.

redrocker

The problem is my USB Protoboard will only work if the usb cable from the computer is still plugged in during boot up.



About an hour ago I was ecstatic. I had just finished the first working version of my very first project. Everything is running fine, so I decide to download the program to the EEPROM and remove the USB Cable.
When I the switch on the power at first everything seems normal. The LCD screen has loaded the first page and gives me a menu, but when I press a button on the key pad nothing happens.

Has anyone ever had this problem before?

More INFO:

The program is loaded and verified in EEPROM.
If I remove the USB cable shortly after power up everything works fine. (?)

There are many devices in the project. So I thought I would first trouble shoot the keypad and LCD. I wrote a simple test program that displays a number for each key I press on the LCD. I then demonstrated that the program works on my PPDB( parallax professional development board). That is I loaded the program to EEPROM, unplug usb cable, powered off/on to success.

However, when I load the exact same program (to EEPROM) to the USB protoboard, unplug usb cable, power on--Nothing. Do the same thing with the cable in=success.

Any suggestions would be greatly appreciated.

Thanks

Adam

James Long

redrocker said...
The problem is my USB Protoboard will only work if the usb cable from the computer is still plugged in during boot up.



About an hour ago I was ecstatic. I had just finished the first working version of my very first project. Everything is running fine, so I decide to download the program to the EEPROM and remove the USB Cable.
When I the switch on the power at first everything seems normal. The LCD screen has loaded the first page and gives me a menu, but when I press a button on the key pad nothing happens.

Has anyone ever had this problem before?

More INFO:

The program is loaded and verified in EEPROM.
If I remove the USB cable shortly after power up everything works fine. (?)

There are many devices in the project. So I thought I would first trouble shoot the keypad and LCD. I wrote a simple test program that displays a number for each key I press on the LCD. I then demonstrated that the program works on my PPDB( parallax professional development board). That is I loaded the program to EEPROM, unplug usb cable, powered off/on to success.

However, when I load the exact same program (to EEPROM) to the USB protoboard, unplug usb cable, power on--Nothing. Do the same thing with the cable in=success.

Any suggestions would be greatly appreciated.

Thanks

Adam

There are a couple of things you didn't mention.

Are you powering the circuit from the same supply for testing both items?

This sounds like a power problem, not an EEPROM problem.

If you can cycle power after a download to the USB protoboard, with the USB cable plugged in, and the propeller work....then the EEPROM is working correctly. After power off the EEPROM has to supply the program to run.

EDIT.......sorry....are you saying if you boot the protoboard with the cable it works, even after the cable is unplugged???

James L

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James L
Partner/Designer
Lil Brother SMT Assembly Services

Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits. Learn to build your own Gizmos!

Post Edited (James Long) : 10/30/2009 8:11:46 PM GMT

James Long

If the last edit is the case..

I think the eeprom is only being totally powered from the USB cable.

You may need to ohm out the eeprom connections on the protoboard. You may find a power/ground trace to the eeprom (from the regular power supply) to have a problem.

James L

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James L
Partner/Designer
Lil Brother SMT Assembly Services

Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits. Learn to build your own Gizmos!

mikediv

I agree with Red but we still need more info I had something similar happen and it turned out to be power related with the USB cable plugged in it seemed to supply some power to my proto board enough to work but when I un-plugged cable the batteries were to low
I have seen this happen a few times I do not have a PPDB is it the same I/O as your proto board? are you using the same size eeproms in both circuits? 256,512,1024?

MagIO2

Is there a pullup on the propeller reset line? Maybe the USB-chip has a free floating output which tends to ground in case there is no power via USB-plug.

Phil Pilgrim (PhiPi)

This is a known issue that has nothing to do with the EEPROM. What's happening is that the USB keeps resetting the Prop when the USB cable is unplugged, due to being powered through an I/O pin. There have been numerous threads that address it:

http://forums.parallax.com/showthread.php?p=651731
http://forums.parallax.com/showthread.php?p=790298
http://forums.parallax.com/showthread.php?p=774972

-Phil

James Long

Phil Pilgrim (PhiPi) said...
This is a known issue that has nothing to do with the EEPROM. What's happening is that the USB keeps resetting the Prop when the USB cable is unplugged, due to being powered through an I/O pin. There have been numerous threads that address it:

http://forums.parallax.com/showthread.php?p=651731
http://forums.parallax.com/showthread.php?p=790298
http://forums.parallax.com/showthread.php?p=774972

-Phil

That is interesting reading......thanks Phil. I had missed those threads in the past.

Thanks for adding the information.

James L

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
James L
Partner/Designer
Lil Brother SMT Assembly Services

Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits. Learn to build your own Gizmos!

redrocker

Wow. I love these forums. Have not failed me yet. Thank you everyone for your quick responses.

Will not get around to correcting the problem unitl Monday but I am sure the 1K pull up or removing the Debug software will do it.

Thanks Again!

Adam