How do I hook up an LCD? (2x16 Backlight)

Masterchief1517

I just bought one of these off ebay, the numbers on the front are YJ-162A, on the back RL 94V-0, YJ-162A,·plus R1, R2, R3, R4, R5, R6 which the "R" ones are next to solder spots. All I have is this screen and a BOE with a BS2. So again, how can I hook this up?

Masterchief1517

Hold up, I do infact have the backlit LCD, BUT it doesn't have the controller on the back of it, so the "pins" on the top of the chip have nothing soldered to them, how can I hook this up to a basic stamp or picaxe?

Post Edited (Masterchief1517) : 5/13/2007 8:39:04 PM GMT

Forrest

It sound like you have a parallel HD44780 based LCD. Yes, you can hook this up to a Basic Stamp - this question pops up every other week on this board. Check the manual to the Parallax parallal LCd here www.parallax.com/detail.asp?product_id=603-00006 or google Stamp to parallel LCD, there's lot of info.

Masterchief1517

No, I don't have that, it has no cable attached to it like that, and it has the exact same build as the serial 2 x 16 except there just isn't any controller on / with it. *EDIT* I did some googling, I discovered this is made by some chinese company or something like that, BUT it has the same dimensions as the backlit 2 x 16 parallax screen.

Post Edited (Masterchief1517) : 5/14/2007 3:29:21 AM GMT

Mike Green

From the label on the back, it does look similar (as Forrest said) to the Parallax parallel LCD. Follow his suggestions and you'll just have to experiment (and add your own cable).

Masterchief1517

Okay... I'll check out some things... But if I have no luck, my voice (hypethetically) will speak tomorrow!

Masterchief1517

Okay, well I'll be using a BOE with a BS2 chip, so, assuming this is just like the parallel 2 x 16 screen, could someone explain to me how exactly to wire this up, preferrably in 8 bit mode, because there is a diagram a kinda already understand for 4 bit mode.

Masterchief1517

Does anyone know which pin to wire each of these to? VSS(duh), VDD(duh), V0, RS, R/W, E, D0, D1, D2, D3, D4, D5, D6, D7.

Wynand

Masterchief1517,

Vdd = 5v
Vss = GRND
Vo = Contrast on LCD, wire it to GRND for max contrast
RS = Register select
R/W = Read from LCD, Write to LCD (low = write, high = read)
E = Enable (to put data sent to data register to be displayed)
D0-D7 = Data Bits
Pin 16 on LCD· = LED+ = Vdd for led backlight connect to 5v··· (change arround if backlight doesn't come on)
Pin 15 on LCD = LED- =· Vss for led backlight connect to GRND (change arround if backlight doesn't come on)
Now, wire Vdd to the 5v line on the BOE, Vss and Vo to the GRND (gound) of the BOE.
Now, wire RS to pin0, R/W to pin1, E to pin2, D0-D7 to pin3-pin10 of the STAMP on the BOE.
Then, all you have to do is to write the software to send the data to the lcd, and me personally prefer as serial lcd, becaue I save·9 pins on the STAMP, and I just have to use the serout command to get characters onto the screen.

Hope it helps,

Wynand.

I am ataching a datasheet on the HD44780 controller, read through it and it will tell you how to interface with the lcd.

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Why didn't I think of THAT!!!!

Post Edited (Wynand) : 5/14/2007 7:36:15 PM GMT

Masterchief1517

I could gives you a thousand dollars for that help there, but unfortunately, I don't have a thousand to give away·· But when I bought this off ebay, I thought I was buying a serial screen, oh well, time to heat up the soldering iron!

Wynand

Masterchief1517,

If you get it working, let us know.....

And good luck.....

Wynand.

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Why didn't I think of THAT!!!!

Masterchief1517

Okay I think it is wired up correctly now, I used the source code from the site, I hope that wasn't a mistake, cause now when it boots, the backlight turns on(good), but the "text" is just the top row being filled with dark boxes. I noticed a part of the code that says "set to 4-bit operation" This is wired in 8-bit I believe, so shouldn't it be starting in 8 bit? If so, how do I do that? Here is that entire subroutine: Init_Lcd:
PAUSE 200
OUTS = %00110000 ' Reset The LCD
PULSOUT E,1 ' Send Command Three Times
PAUSE 10
PULSOUT E,1
PAUSE 10
PULSOUT E,1
PAUSE 10
OUTS = %00100000 ' Set To 4-bit Operation
PULSOUT E,1
Inst = %00101000 ' Function Set (2-Line Mode)
GOSUB Send_Inst
Inst = %00001110 ' Turn On Cursor
GOSUB Send_Inst
Inst = %00000110 ' Set Auto-Increment
GOSUB Send_Inst
Inst = %00000001 ' Clears LCD
GOSUB Send_Inst
Inst = 14 ' Set Cursor To Underline
GOSUB Send_Inst
RETURN

Masterchief1517

Quick clarification here, where is says "OUTS = %00100000 'Set To 4-bit Operation" , I was wondering what value you would you to set it to 8-bit mode?

Chris Savage

Since you aren’t using 4-bit mode you simply omit that line along with its GOSUB call. By the way, the attached (above) datasheet covers the initialization sequences. They’re listed right in there for both 4-bit and 8-bit modes. See page 45. Take care.

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Chris Savage
Parallax Tech Support

Masterchief1517

Oh, sorry about that, thanks a bunch, I got just about sick of reading that thing around page 35, lol.

Masterchief1517

Ummm, what is the normal sign that your lcd is dead (by wiring it wrong) Can your program destroy your lcd (by telling it to send something through the wrong pin) Cause when mine starts up, it just shows the top line being covered with blocks, and it won't go away, I made sure it wasn't the program either by unplugging the data cables

Post Edited (Masterchief1517) : 5/15/2007 2:36:02 AM GMT

Forrest

Do you have the wiper of a 10K pot connected to pin 3 (Vo) on your LCD? Try adjusting the pot.

Masterchief1517

I'm not using a pot, cause I was told hooking right to ground was fine, should i hook a 10k resistor to it? I could wire up other resistors to make it between 10k and 20k.

Wynand

The black boxes accross the top line means that the lcd has power, but has not recieved initialization, ie has not revieced the turn of/turn on, clear screen instruction.
Makes shure that the pins in the program correspond to the pins that you wired to your LCD, ie that the data bits run from pin3-pin10 and the instruction bits are run from pin0-pin2. If I look at the code you posted, it should work. Just remember, when you run it in 8 bit mode, you have to add outputs to the instruction line of the demo program, else you will lose the 3 last data bits (since you are only addressing pin0-pin7 instead of pin0-pin10).

I hope that this clarifies it for you....

Wynand.

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Why didn't I think of THAT!!!!

Wynand

Ok, so I have done some thinking, and tweeked the demo program.

Your pins should be connected as follows:

STAMP················· :·················· LCD

pin0····················· :················· D7

pin1····················· :················· D6

pin2····················· :················· D5

pin3····················· :················· D4

pin4····················· :················· D3

pin5····················· :················· D2

pin6····················· :················· D1

pin7····················· :················· D0

pin8····················· :··················RS

pin9····················· :··················R/W

pin10··················· :·················· E



Then download the demo program attached, and run it to see if it works.


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Why didn't I think of THAT!!!!

Post Edited (Wynand) : 5/15/2007 8:09:45 AM GMT

Masterchief1517

Not quite, but I did add a 10k resistor and that got rid of the blocks.... Nothing else came up on the screen, I'll run the default program again, with the right I/O set.

Lmiller1708

Hello,
I have had this same problem. Have also the same display but it is alittle larger. I have posted this same question on the SX forum:
http://forums.parallax.com/showthread.php?p=650172
But have not found any simple code like what is shown above.
I do not have a·BS2 and know this is not the right forum, but was just wondering if anyone has simple code like this in SX/B.
Thanks,
Lance

Wynand

I just hope that you didn't set the contrast so low that the block dissapear,meaning nothing else on the lcd will display. I have exactly the same lcd connected to the parallel port of my pc, and when I start it up, black blocks, but as soon as the program starts to send it info, bob is your uncle and it displays everything as it should. Look, by no means do I sell myself out as an expert, I jst think that we have the pin-outs wrong, so it is a matter of programming and logic thinking...................still thinking.........................still thinking............................pleased help me people!!!!!!!

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Why didn't I think of THAT!!!!

Masterchief1517

Well, either way, with your program and no resitor, just blocks, your program and 10k or 4.7k resistor: no blocks, no text. If anyone here has a serial lcd, they can tell me all the parts I'd need to get to build the "backpack" which I could then attach it to the screen and wire in serial!

Masterchief1517

Isn't serial mode just telling another chip, which is wired in parallel to the LCD, what character to send next?

PJAllen

The serial backpack is an interface which takes serial data from a Stamp and converts/performs all of the memory-gobbling house-keeping and choring·(i.e. all of the "code" required to run an LCD directly.)· Anyway, it's a micro-controller in itself, actually.· If you don't want to buy a Parallax serial LCD (tsk-tsk), you could order one of these kits (they're very good) --

cgi.ebay.com/Serial-LCD-Kit-117-w-20X4-LCD-Basic-Stamp_W0QQitemZ140118573324QQihZ004QQcategoryZ4661QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

or one of these ICs --
http://www.allelectronics.com/cgi-bin/item/EDE-702/285/LCD_CONTROLLER_IC_.html

Update:
Here's another kit, nice if you have a considerable·box-of-parts already·(IC & PCB, but other necessary components are extra) -- http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=10799

Post Edited (PJ Allen) : 5/16/2007 12:41:59 AM GMT

Masterchief1517

HOLY $&!^!!!!! I got it partially working, I wired it up for 4 bit mode, now there is just 1 box on the far left, and the '&' symbol on the bottom right!

Masterchief1517

I have a picture of this ... funky... text

firestorm.v1

The LCD is in "chinese mode", Check a pin, I think you got a bad connection somewhere. The Chinese and English character sets are offset by only a couple of pins, if one is shorted, then both might register as high. As a suggestion, if you're bored (AND you've checked our connectors) each of those characters refers to a 8 bit word, Use the character map to find what those characters represent, then you should see the common pins to take a look at. What were you trying to get the LCD to say? It might not be a bad idea to do the same for what you were expecting the LCD to say, so that way you can see which pins are working and which aren't.

This is a page that has a lot of detailed info about LCDs, but all we need is the character map : http://home.iae.nl/users/pouweha/lcd/lcd0.shtml#charset

Other LCD links that might help:

http://www.electronic-engineering.ch/microchip/datasheets/datasheets.html - A lot of good information for parallel LCDS, may be helpful
http://www.geocities.com/dinceraydin/djlcdsim/djlcdsim.html - Javascript Parallel LCD simulator. (Learn what all those codes do)

RDL2004

In addition to PJ Allen's links, here is another source for the Peter Anderson serial kit:

Wulfden.org

I bought one of the 4x20 blue serial LCDs from the PHAnderson Electronics eBay store last summer and it works great. It's so bright you can almost use it as a night light.

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- Rick

Masterchief1517

yeah, I saw that site yesterday, but the k107 page wan't working right at the time :-(, but now it is, so thanks! I'm digging around fo rthe cheapest board I can find.