We are using EMX 1.1 with firmware version 4.1.3.0 in our controller boards. We have been using it for a few years in our production, and once in a while we hear from our customers that it does not power up. I understand that this part is obsolete but we have a lot of them out there and it is becoming a growing issue for us.
What happens is that as soon as it powers up the display turns black or white and it doesn’t get fixed with a power cycle. The only way to fix it is to remove a jumper in the board that grounds the LMODE pin. LMODE is grounded through a jumper to use USB for debugging.
At this state if we take the jumper out and let LMODE unconnected and cycle power the problem goes away for some time, but the catch is that we can’t use it like this, so we have to put the jumper back in and recycle power again.
It looks like that the system stops at BootLoader or TinyBooter. When the issue happens I do not see debugging messages with TeraTerm and PC does not see EMX module through USB.
This is very random and we cannot relate it to any hardware issue because a system may work for a while and suddenly start doing this.
We have up, down and select pins unconnected and even having them high does not fix the issue.
I appreciated any help.
@ ssalmi - About how often does this happen? When the problem happens, before you remove the jumper, can you verify that LMODE is actually pulled low?
I’m sure John can help you, but have you read this post?:
[url]https://www.ghielectronics.com/community/forum/topic?id=20060[/url]
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