Matrix Orbital Corp

Hi, I am trying to connect my WIZ220io remote I/O module from Wiznet to a LK202-25 LCD screen. But I am having some troubles. The Wiznet module has UART output, I can communicate but all I see is some garbage text. This is my setup:
1) LK202-25 on 12 volt.
2) Connected the WIZ220io module with 5v pin and ground (those near the GPOs)
3) The TX pin to WIZ220io RX pin and the RX to the TX pin
4) Sending some text will display strange characters but LCD works fine when connected to my PC

I thought it was a baud issue but they operate at the same speed. Is it a grounding problem? And how can it be solved. I am a beginner at electronics!

Thank you for your help.
Harm

Hi Harm,

I'm not familiar with the Wiznet module, but I'll take a look at the documentation and see what I can find.

In the meantime, you might try swapping the Rx/Tx lines, and checking to confirm the Wiznet module is not only operating at 19200 baud but uses an 8 bits data, No party, 1 stop bit configuration with any handshaking turned off.

Thanks,
Troy

Hi Harm,

Looks like WIZ220io module outputs TTL level signals. If your LK202-25 is communicating correctly with your computer at RS232 levels, you'll have to put it into TTL mode to communicate with your WIZ220io.

Essentially, you'll have to remove three zero ohm resistors labelled 232 from the protocol select block and reuse two of them, or some solder, to connect the two TTL pads. Full instructions are available in your manual.

Thanks,
Troy

Hi Troy,
Great this sounds like a solution. I didn't know the difference between rs232 and TTL now I do.
Wouldn't have figured this out on my own, will report back when I got it working.
Harm

Great! I have got it working. Thank you for your advice.
Harm

No worries Harm, great to hear you are up and running!
Troy