Well I believe I have officially solved a doosy of an electronics problem, which now seems pretty obvious (Isn't that always the case).
I have been banging my head against the wall for weeks trying to understand why a bit of RF noise in the 100MHz range would cause a product I was working on to lock up? Also once I fixed that issue, why one type of display would work and the other would break?
It all boils down to the two displays even though schematically the same used different amounts of ITO to connect the SDA line and GND line of the Chip-On-Glass LCD controller to the metal flex cable. That increased resistance on the SDA & GND line (~400 Ohms on one display and ~200 Ohms on the other) casue the Ack I2C signal coming back from the LCD controller to read as a logic "1" instead of the proper "0". By changing the SDA & SCL to higher value pullups on the display the ITO resistance effect is less noticable. Obvious now right :p
Well I am going to celebrate with one of my favorite beers (Crow Peak Porter brewed in Spearfish, South Dakota, USA) and sulk a bit because I now have a lot of work ahead of me documenting this issue and updating the three pieces of my design that now need correcting.
Is that coke? Looks like rum and coke don't you think? Thanks for share and keep up the good work.ReplyDelete
Just would like to thank you for this special read. I definitely savored every little bit of it including all the comments and I have you bookmarked to check out new stuff you post.ReplyDelete