Not printing correct char's with 632


New member
Hello, I just purchased my first lcd and am trying to get it to work with my microcontroller. I am using an inverted RS232 protocol. The jumper settings on the lcd are:
JPA = Open
JPB = Closed
JPC = Open
JPD = Open
JPE = Closed
JPK = Open
JPL = Open
When I hook everything up and send a character, I get something completely different. For example, I send an "A" and get back some funky character that I cant even describe. I have changed the character sent a few time and the output does change as well, so it not like something is stuck on the lcd. I looked at the waveform with a scope and it looks like I would expect. For the "A" above, I see "1011111010". This is assuming 1 start bit, 8 data bits and 1 stop bit. I don't think this is that hard, but I am obviously missing something. Any thoughts?? Thanks.
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USB LCD Displays - Graphic and Character LCDs with a Keypad

CF Tech

What is the LCD Rx pin connected to?

Is it the processor's "UART Tx" pin, or the output of a "Max232" type chip?

What are the levels for 0 and 1 on your waveform?


New member
After a litte more investigation, I found that the lcd was interpreting the data as if it were not inverted, even though JPB was closed. I did verify that the data was in fact being sent to the lcd inverted.

When I opened JPB the lcd work great!?! I dont really understand what is going on.