LCD powered by a PIC issue

[fifipil909]

Hello everybody,

First Thank you Jeff and everybody sharing information regarding this project. You did a great work.

I decide to use a LCD 16x4 with a HD44780 chip but powered with a Microchip PIC 16F873.
The program is working fine, I add a line shift function which is looking good. I use also a "Rotatif Coder" for the station change.

My problem is, I try the LCD display with my computer interfacing with a MAX3232. No problem at this point eveything is fine.
When I connect the LCD on the router I get funny thing on the RX buffer. ( I use 9600 baud on both side).

The serial connection work between my computer and the Router with the same MAX3232 adapter
The serial connection work between my computer and the LCD display with the MAX3232 adapter

My PIC/LCD have a 5V power supply, I put 2x 1n4007 diode to put down the supply to 3.8V because I was thinking that PIC had some issue to get the 3.3 V input level from the router.
But same thing.

Do you have any Idea ? Do you know if something have to be change on the Router serial port configuration ?
Thanks
Vincent.

[fifipil909]

Hello
I find the issue.
my Uart Interrupt function was not fast enough.

It's solve. I wil post my code and schematic when it will be 100% done.

Vincent.

[mightyohm]

Hello,

It is good that you fixed your issue. Do you know why the UART was fast enough to talk to your computer, but not fast enough to talk to the router?

Also, keeping the signals to the router at 3.3V max is a good idea, I don't know if the WL-520 serial port can tolerate 5V signals without damage.

[fifipil909]

Hi Jeff,

When I did my test with the LCD connected to my computer I sent "Name: My test radio" through the UART Letter by letter.
But when I did the same thing with the WL520 the same sentence is sent in one shot, so I missed some data during the buffer processing.

I just solve the issue with doing the Buffer processing only when "/n" is received.

Vincent.

[mightyohm]

That makes sense. Glad you got it fixed!