Introduction: InterActive 4 Dumb Terminal
Making a Dumb Terminal out of an old DMC 16117A 1x16 LCD display. First thing to do is to get a Serial Interface for the display. I am using a SparkFun.com SerLCD for this. The 16117A only has 14 connectors and that is fine. The 15 & 16 connections on the SerLCD are for the back light Leds. Just carefully cut the header and remove those connectors. Install the SerLCD on to the 16117A. Connect Power, Ground and Rx to your processor port. Serial communications is vanilla 9600 baud, 8 bits even or true, 1 Start bit, 1 Stop bit, no parity.
I am just using fragments of my code for this article. It is the same code I used for the Serial E-Prom article. I just changed the output drivers to handle the 16117A display. The TXT file has the code fragments.
If you want back lights you will have to remove the mirror backing on the 16117A. On mine the foil was on another piece of plastic. I removed all of it. The lights can be anything. Connect them plus voltage to 15 and ground on 16.
I do not remember when I got my 16117A. It was one of the first LCD display available for processor boards way back in the mid 90’s. No one did much with it because of its horrible tedious Parallel interface. The serial interfaces now make it great for a dumb terminal attached to a processor board like the Basic Stamp 2. You still have baby this display and the processor board helps. Power glitches and static discharge send the 16117A into uncontrollable states that only a correct series of commands can fix. The Parallax.com Basic should be easy to translate into other systems.
The 16117A controller is for multi-line displays. The 16 byte display is really two 8 byte lines in the display’s memory. 0-7 for the first line and 64-71 for the second line. In my program to make the cursor position you add the control character 128 to it. That tells SerLCD that it is a cursor position. The memory is a mess. See the manual.
Having the SerLCD gives you all those pins to do other things with. Run switches for user feedback. Run things for the user interface. Make a bigger interactive thing. The display keeps the users informed. And the 16117A looks almost normal thanks to the other processor board. Just to send a long string to the display you need a processor. Send first 8 letters then set the cursor position and print the rest of the string to the display. That is what my interface does.
Every processor board supports Network Serial communications on most their pins. Networks must have the grounds connected or they will not understand each other. Minimum is Rx and Ground. Long network cables should be shielded twisted pair cables. Pull up resistors is all you need. About 47K. See my InterActive articles. I have not got the network stuff done yet, so no code file this time. I wish I had friends to share this with. I am a very lonely geek in LA.
We have a be nice policy.
Please be positive and constructive.