LPC1768 loosing flash settings

Electronics and hardware Boards
1

Hi, I’m using an Mbed LPC1768 with a web server and GPIO. I’m using IAP flash to save user configuration settings, but I’m having some intermittent issues with a few different devices. As the issues aren’t related to each other, I can’t figure out what’s going on.

  1. Sometimes the user settings go back to the default configuration settings when I power on the unit the next day (such as IP, port, and other user settings). I had this problem for a few days last week, but for the past four days, it’s been stable and worked every day with the saved settings when the unit powers up.
  2. I’m using Power over Ethernet (PoE) to power up the LPC1768. Sometimes it doesn’t work with Auto-negotiation on the Cisco SG300, and I have to force the SG300 port to 10mb to get it working. Sometimes it doesn’t like 100mb speed.
  3. When I format the MBED and copy the same firmware file, it works. But I never know when it’s going to give me an issue. Some times it works weeks without issues

Any thoughts or ideas would be lovely.

Many thanks.

2

Hi,
Just some thoughts, many may be obvious but I include them just in case.

  1. a Check your code used to save to flash. Are all the coded time delays within the specs for the part.
    1 b. Check for dry joints or loose connections.
    1 c. If you power down immediately after flash programming give the flash time to save the data before you power down.
    1 d. Measure the supply voltages to ensure they are within manufactures spec. Could be related to your issue 2.
    1 e. Try powering the LPC from an external supply other than the PoE.

2 a Check your LPC Ethernet code and clock speeds, are they within spec and consistent with timings required by the Ethernet connection.
2 b Try different Ethernet cable.

Overall the main points are: 1. Loose connection. 2. Power issues. 3. Timing issues within the code.

Good luck