using spark funs huge lcd with prop anyone get it to work?

mikediv

Hey guys I am just not having any luck with LCD's I boguht the spark fun huge LCD it really is huge by the way 160x128 and almost 6 inches across, anyway I am trying to connect it to my prop educational kit with prop stick usb

here are the pin outs
PIN SYMBOL FUNCTION
1 FG FRAME GROUND
2 Vss Power Supply(GND)
3 Vdd Power Supply For Logic(+5V)
4 Vo Power Supply For LCD Driving (Contrast Adjust)
5 VEE NEGATIVE VOLTAGE INPUT/OUTPUT
6 /WR DATA WRITE
7 /RD DATA READl
8 /CE CHIP ENABLE FOR T6963C
9 C/D COMMAND/DATA SELECTION
10 /HALT CLOCK OPERATING STOP SIGNAL
11 /RST RESET T6963C(LOW EFFECTIVE)
12--19 DB0—DB7 DATA BUS
20 NC NO CONNECTION

21 LEDA LED BACKLIGHT POWER SUPPLY(+)(+5V)

I connected the data lines 0-7 to prop pins P0-7 going through 1K 1/4 watt resistors , I also tied the reset of the LCD to ground using a 20mf pico cap, I have a seperate 5V power supply ut using shared grounds. anbd I tied the write data pin to the clk out using some simple prop spin commands randomly dira and outa to set the output pins to high or low I was hoping it would put somehting on the LCD but nothing I would like to just be able to test out the display any thoughts? Thank you

JerryN

I haven't tried hooking mine up yet but check these two references:

http://forums.parallax.com/showthread.php?p=765574
www.rayslogic.com/propeller/3rdPartyHardware/3rdPartyHardware.htm

From the second reference: "Data bus pins are backwards from datasheet! Pin#12 is the MSBit and Pin#19 is the LSBit...". Might this be your problem?

Jerry

mikediv

Thanks Jerry I knew about the backward pins for d0-7 I think I don't have the device interfaced correctly I am going to make up a schematic of what I have hopefull that will help others help me debug
I connected D0-7 to the prop pins P0-7 with 1K resistors in line I think I dont have the other pins connected properly
I put a 10K pot between VDD and VEE with the wiper part of the pot on pin 4 VO but I do not know what other pins to connect
I knew about rays post thats why I bought this LCD its and awesome display by the way , ut he does not show what pins to connect to anyhting his code is nice but if you dont know how to interface the hardware its not much help
Thanks again

·

JerryN

I will try to get mine hooked up one of these days - unfortunately my "round tuit" file just keeps getting longer, not shorter.

Jerry

Rayman

One thing I noticed is that you don't mention pin 22...· This is the cathode connection to the LED backlight, so you have to have this connected to ground to see anything...

·

mikediv

Thanks Rayman I have pin 22 connected to ground the display lights right up, the backlit is working fine I have +5 to 21
22 is grounded
Pin 3 is +5 volts that goes thorugh a 10K pot to pin 5 pin 4 VO goes to to middle of the pot or wiper
DB0-DB7 go to prop pins P0-P7 through 1K resistors so DB0

---

\\\/\/\/\/

---

1K resisotr Prop pin P0
pin 11 reset I have a 20 pico cap right to ground so pin 11 LCD

---

(cap)

---

ground
I did not use frame ground I just tied pins
6 /WR DATA WRITE
7 /RD DATA READl

8 /CE CHIP ENABLE FOR T69 all through a oull up 1 k resistor to +5 I didnt know what else to do with them and thats it so I am pretty sure I need to do something with more fo the pins, then I just wrote some random spin code dira: outa to the data pins just on or off hoping it would do something on the display so I could at least confirm its working

Ray if you get a chance I would love to know what pins from the display you connected to the prop pins?

Or if anyone else has any recomendations

Thanks all

Rayman

I think you get tell the pins I used from the code I posted...· Pretty sure it's all given in the constants section.

I think you need to toggle CE in order to read or write from the device...· So, it need to connect to a Prop pin.

I'd suggest you look at the datasheet or the driver code I posted...

Also, I think 20pF for that reset cap might be too small.· I think I used 100nF...

mikediv

Thanks Ray I have been trying to figure out what pins you used via the spin code but to be honest its a little bit above me right now I am new to the prop and have never ever interfaced an LCD of any type I have not even played with them so I am trying to understand the things from a beginers point the data sheet means little to me from what I see its how to program the lcd driver chip, I am still at what pins on the LCD should go to what pins on the prop chip , like I said the display backlight comes on and I do have data pins connected to prop pins but thats it , I know you said a few times to look at your post for pin connections but I have no CLUE where your posts show them???? I even downloaded the PCB software you used but all it shows is your circuit board layout
so unless I more blind than I already think I am you must be talking·about somehting I just don't see. I still think I need to have more pins connected to the prop while I have the data 0-7 thats it, I·saw in data sheet about /WR and it says to toggle it high for read but then next line says 90ns so does that mean I should strobe the /RW with a 90ns square wave,, I do appreciate everyones help and I am determined to figure out the LCD displays if it kills me I have several projects with Pics and·props that are just begging for a simple display ..
·

Leon

/WR has to be driven high for 90 ns, from a low state. it doesn't need a continuous square wave, just a single pulse.

Leon

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Rayman

Here's the CON section from my driver (that you can download from the forementioned links):

CON  'Constants Section
  'Control Pins
  WRPin=7
  RDPin=6
  CEPin=5
  CDPin=4
  'Data Pins
    'Note that the PINS are actually backwards from what the Datasheet implies!!!
  'DataBasePin=8   '<===  I thought this was going to be the LSBit
  'DataEndPin=DataBasePin+7
  DataEndPin=8     '<=== Easy to read the pins backwards with Spin
  DataBasePin=DataEndPin+7

I think the easiest path for you is to change these pin definitions to match what you have and try out my test file that uses this driver...

mikediv

thanks leon rayman duh I feel stupid , do you know how many times at looked at that part of the code then the pinout datasheet and didnt make the connection. Well I said I was blind your right its all there I am very sorry I kept asking
.. If I get this to work I will let you know thanks again
the rest of your code is a bit complex for me but now I have a starting point to help figure out what you were doing with it
thanks again
·Oh Ray in your code you state that you have to manualy enter pins?? can I ask where in the code? I am asuuming by that you mean to enter what LCD DB0-7 pins that are connected to the prop right? thanks

Post Edited (mikediv) : 12/27/2008 1:10:09 AM GMT

Rayman

Given your pins in the first post, change "DataEndPin" to 12, WRPin to 6, RDPin to 7, etc...

mikediv

Rayman I just left the pins WR,RD,CE-etc the way you have them in the code and just moved my DB0-7 lines to P9-16 respectivly

I wired it all up on wirless proto board so its easy to change anything , I am giving it a try as we speak I did notice I forgot to install Vss to ground but the backlight is so bright on this thing , from the datasheet it looks like that 10K pot is only for the charactor contrast there is seems to be no way to adjust the backlight is there thanks again.

Rayman

I suppose you could try powering the backlight from the 3.3V supply...

mikediv

good point I guess I could just use a pot but I wasn't ·complaining just talking/typing out loud, I bet it would work well outside in sunlight , Rayman you never did say what you were doing with your display , there seems to be a few others that bought this LCD based on your post if you do a google search you come right up I bet its going to be very popular , well thank for being patient and the help
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