Electronics > Beginners
How to drive a old controllerless lcd? Hitachi LM236XB
funder_benz:
Hi there, this is my first post here. I saw some videos on youtube about Dave, and I think that this is the right place for me to find an answer.
Well, I'm not an expert at all, I've been messing around and being interested to electronics since when i was a child, now I want to learn something new.
My goal is to make an audio spectrum analyzer, so I was thinking about which visual device will be the best choice to display what I want.
Some time ago I bought an old Aval Spotlink "The Teleterminal", it was working, but in fact, useless, so I thought to use its lcd for my project as its big enough and reminds me to my gameboy somehow.
Actually I've got an arduino, and I've tried to hook up the thing up and figure out how does it work. I've found some info on the net, but really, not very useful to me.
I need to study a lot to be able to understand how this device works, probably it's not the best piece of hardware to start with, but anyway, I don't want to give up, absolutely.
This thing needs a good refresh rate, which is (I think) impossible to achieve with only an arduino and no "interface" between it and the lcd.
But, that Aval Spotlink, made in the 90's did it, so there should be a way to do that.
Probably, the best thing it's to hook up a logic analyzer to the Spotlink, power it up and see what happens with a logic analyzer, but it's not working anymore because I've disconnected some parts from the mainboard (DOH). Anyway, I don't have a logic analyzer, only a 20 mhz analog oscilloscope with memory function.
I've got a power supply that can provide +12 -12 +5 -5 volts .... maybe is not good enough but using the -12 and -5 v I should get 17v. The lcd power up but the only thing that I was able to visualize were random lines. Probably I need some sort of filters on the data lines, but as I said, I'm not an expert.
The lcd is a Hitachi LM236XB ... you can find a datasheet for the SB which must be identical (just some little difference in the view angle and stuff like that).
I will buy a STM32F4 discovery board because I'm really interested to learn on that platform, I think its well suited for hi-quality audio applications. Probably it's better to start on simpler devices like arduino, but I don't know ... that thing looks better to me >:D
Well, that's the story, I hope someone can give me some information to start with, any kind of help will be really appreciated!
Here are some photos of the lcd. Front, back ICs, and some parts of the datasheet...is that enough?
THANKS!! :-+
funder_benz:
up
CodeRed:
I saw your comment on my blog, I'll leave a link to that article here for everyone else.
http://burnt-traces.com/?p=246
For my implementation, I created a state machine based solely on the timing diagram for the LCD interface. I used a low end FPGA, while the implementation I referenced was based in a PIC micro with some external memories.
http://www.nyx.net/~jpurbric/lcd/
You should be able to do it with your STM board, you just have to be able to toggle pins as fast as the fastest signal, which based on the diagram and some quick math, is about 1.2 MHz. I dare say the arduino might be able to do it, but it probably won't be able to do anything else at the same time.
Whatever method you choose, I would start with trying to duplicate the timing diagram. You should be able to verify that with your scope, no need for the logic analyzer. I have a post where I probe a more modern LCD interface with my analog scope.
http://burnt-traces.com/?p=290
janoc:
--- Quote from: funder_benz on November 12, 2014, 01:29:29 am ---up
--- End quote ---
Please, don't "up" your own posts like this - it is bad form, it pollutes the forum and it still won't get you an answer any faster. People work, you know, so few get to read the forums more than once in a day or two ...
J.
Bassman59:
--- Quote from: funder_benz on November 11, 2014, 02:13:19 am ---Well, that's the story, I hope someone can give me some information to start with, any kind of help will be really appreciated!
--- End quote ---
That LCD's interface is 5V, so make sure your micro can tolerate it.
Navigation
[0] Message Index
[#] Next page
Go to full version