Serial LCD support question...

KamPutty

Hi all!

Hope you're all doing well!

Okay, I'm finally getting around to connecting my serial lcd. It contains 3 pins, +5, -, and serial. (seetron #bpp-420vy)

I've attached a level shifter for my rs232 support (http://www.sparkfun.com/commerce/product_info.php?products_id=449)

I'm running +5 into the shifter and lcd.

Okay, my question is, for the serial lcd support, is there a list of lcd's that it works for? In other words, will the seetron I'm using work?

~Kam (^8*

Drone

I think the Serial LCD and Debug LCD objects in the Parallax Object Exchange are optimized for the Parallax LCD's, like the Parallax P/N 27979 4X20-line back-lit LCD, which is similar in form and function to your Seetron LCD. The Parallax LCD's have a Parallax SX micro-controller on the back of them that does the serial interfacing and character/command translation to the LCD's parallel interface. There is a special command set for the Parallax LCD's, it is clearly spelled-out in the Parallax data sheets.

I would think that standard ASCII characters, carriage-returns and line-feeds would work ok with the LCD driver objects from Object Exchange with your Seetron LCD, but control functions like clearing the LCD, turning on and off the backlight etc. etc. would probably not work unless you modified the methods in the LCD object for your specific LCD model's command-set. You may compare the command-set in the data sheet for the Parallax LCD with the command-set in the Seetron manual.

Of-course there's nothing to prevent you from using the Seetron command-set by simply sending the proper characters. In this case the LCD objects add no functional value when compared to something like the Simple Serial object which just facilitates serial communications. But like I mention above, the LCD objects may be useful if they can be customized for your specific command set.

When I got started with the Propeller I was tempted to use a more powerful serial LCD. But then after looking at how many objects and examples used the Serial LCD or Debug LCD objects with the Parallax LCD, I just decided to stick with the Parallax LCD to save time. Today it might be worth revisiting this by taking a look at the Debug LCD object to see if it can be customized.

Why are you using the Sparkfun RS232 level translator? Typically these serial LCD's do not require "true" RS232 with +/- voltage, in-fact true RS232 voltages may damage the serial interface on the LCD. The Parallax LCD works by directly connecting the serial lines to the pins on the propeller. If I was connecting the serial LCD to a PC's serial port, then I would use the RS232 level translator.

Good Luck, David