24n That wont respond to com

[sturgessb]

Hi Guys

I have a 24n that just doesn't want to re-program, all I get is 'failed to respond on com1'. It is still running its existing code fine, but just wont flash.
Any ideas?

It does respond to a reset. But when i try to identify device, it comes back as unknown. Is this stopping it flashing?

Thanks

Ben

[dkinzer]

It is still running its existing code fine, but just wont flash.

The message that you cited generally means the device responded to the ATN signal but didn't respond to a command. That means that the device's transmit circuit is functioning properly but its receive circuit is not. This could be because of a component failure on the ZX itself or a problem in the connections to it.

[sturgessb]

Its not the connection as I've just replaced it with another and its fine. It must just be dead.

No matter.

[sturgessb]

Ah I think Ive spotted why!

Excuse the large photo, but look at the IC bottom left.

http://www.bensturgess.co.uk/transmitter/sany0007.JPG


I have an old zx24 can i switch the ICs over?

[dkinzer]

I have an old zx24 can i switch the ICs over?

It looks like it might have been fried. All of the parts that we've ever used for U3 are compatible with one another so they could be swapped if you have the skills and equipment to do so.

[sturgessb]

switched it over but still no joy, never mind, was worth a shot.

Just ordered another. Can this go out today, im pretty desperate for it. Cheers

Ben

[dkinzer]

Can this go out today, im pretty desperate for it.

Sorry, it was too late for the DHL pickup for today. It will go out tomorrow.

[sturgessb]

no worries, thanks Don

[spamiam]

switched it over but still no joy, never mind, was worth a shot.

Just ordered another. Can this go out today, im pretty desperate for it. Cheers

Ben

Hmm, I wonder why the replacement chip doesn't work? Did it get fried too? When you get your new ZX be VERY VERY careful about hooking it up. Is there something wrong with the signal you are sending to the ZX that is killing the chips?

-Tony

[Don_Kirby]

I have the same issue here. I believe mine suffered from either a static discharge spike, or alternatively, I've exceeded the write cycle limit of the flash. I have been using this particular chip for a year or so, and I'm not shy when it comes to uploading new programs. On the other hand, I'm leaning towards the static discharge. My own lackadaisical version control system doesn't even come close to accounting for the number of program cycle necessary to wear out the chip.


-Don

[dkinzer]

[...]I've exceeded the write cycle limit of the flash.

Possible, but unlikely I think. The write cycle limit of the external EEPROM is a million cycles and 100,000 for internal Flash. If you downloaded 200 times a day it would take 16 months to exceed 100,000 cycles.

In any event, we're happy to send you a replacement.

[Don_Kirby]

I happened to be digging through a parts bin today and came upon the dead ZX24n I had mentioned in this thread. It still won't respond to a program load, although it does run the existing code just fine.

I've ordered a replacement for a new project I am working on and was wondering if Elba Corp would like to have the damaged one back for a post mortem?

-Don

[dkinzer]

was wondering if Elba Corp would like to have the damaged one back for a post mortem?

Sure, we can take a look at it. Often, re-flashing the bootloader will revive it. If you agree, we can hold your order and ship it after we've received the non-functional one and examined it.

[Don_Kirby]

No need to hold the order, but thank you for the offer. It's been a fine testbed, and owes me nothing.

If the damaged unit can be revived, perhaps it could be donated to some worthy cause..

Don