• We recently switched our forum platform. If you experience any issues please email support@crystalfontz.com

Not printing correct char's with 632

bigeeguy

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.
Looking for additional LCD resources? Check out our LCD blog for the latest developments in LCD technology.
 

CF Tech

Administrator
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?
 

bigeeguy

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.
 
USB LCD Displays - Graphic and Character LCDs with a Keypad
Top