AXE020 + Serial LCD

[LeonR]

Hi,

I have a Serial LCD here which I used to connect to a PC, using the serial port.

It has 3 pins, GND, +5v and Signal.

I connected GND to GND, +5 to V and signal to output pin 0.

I then used the commands:-

serout 0,t2400,("hello") and serout,n2400,("hello") .

What is n and t?

Also, my LCD is not actually doing anything, the baud rate is set correctly.

I thought maybe the way the output pins function could be causing the problem? as they are usually ground on this board? (or have i misunderstood this?).

If they are ground, then the signal pin will not work I assume and thefore im guessing I need to solder my own pin on somwhere else on the board?


Thanks!

 

[kevrus]

there are a number of reasons why the display may not be working, but as you are using the AXE20, the first thing that I would check is that the data line is connected to output 0 (pin 21 of the 28x) directly (I use a 1k series resistor) and NOT through the darlington driver chip that is onboard

 

[LeonR]

there are a number of reasons why the display may not be working, but as you are using the AXE20, the first thing that I would check is that the data line is connected to output 0 (pin 21 of the 28x) directly (I use a 1k series resistor) and NOT through the darlington driver chip that is onboard

I did try holding the signal wire on pin 0 (21) and had no luck

I also tried it with a 330ohm resistor but not 1k yet.

Just trying to understand serial output so I can use a wireless module in the future (possibly).

Thanks for the advice!

P.S:- The LCD has power as the backlight is on, also when i touch the signal wire random characters appear so i guess it is "listening".

 

[westaust55]

What is n and t?

these are flags used to determine the "sense" of the signal being sent serially.

"t" is a true or normal "sense" of the signal. Simply a bit that is a 1 is output as a high (=1) and a a 0 is output as a low (=0)

"n" is an inverted signal sense. Simply a bit that is a 1 is output as a low (=0) and a a 0 is output as a high (=1)



If it has been working with your PC then it is likely that it may need an RS232 level signal for the data. That is from +12V to -12V. You may need to use a MAX232 for signal level transition.

 

[LeonR]

Ok thanks for that!

Yeh, I tried holding the signal wire on the pin straight from the 28 chip and no luck, so it must need a signal thingy lol


At least I know now. I don't actually need the LCD to work luckily!

My plan is to (adventerous I know) make a robot that can create a 2D map, however as the memory is limited, im going to need to use a wireless link to a laptop I think. Im pretty confident with the software side of things, its more the electronics that I want to learn. We will see! I need 2 lego motors first!!!


Thanks for the help!