Problems with an 122x32 LCD
Costa Constantinou
have tried devices from a couple of manufacturers including the
GM12323 from Data Image Corp. I've checked all the interface timing
against the timing limits. I've also tried almost every conceivable
combination of commands (Dummy writes too). The control commands
appear to work as I can turn the display on/off and switch static
drive on/off etc. The problem is I can't read or write to the Data
Ram.
Has anyone ever managed to get one of these devices working? I would
be very grateful for any advice.
Thanks,
Costa Constantinou
Geraldo Sazias
Assembly (http://www.lcd-module.de/) but haven't yet had the time to check
it out. Most tutorials with code on graphic LCD's assume the controller is a
T6963 which is supposed to become the 'new' standard just as the HD44780 was
the standard with the character LCD's, but most graphic LCD's use a variety
of controllers. The controllers from Samsung (KSXXXX) are also used quite
frequently.
I'll be following this thread with interest to see if anyone has some tips.
"Costa Constantinou" <cost...@postmaster.co.uk> wrote in message
news:c17923ab.0205...@posting.google.com...
Jeroen Smaal
"Costa Constantinou" <cost...@postmaster.co.uk> wrote in message
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What microcontroller are you using to control it?
I've used a 122x32 display (with dual SED1520, bought from Conrad
Electronics) with a 68HC11 successfully. Make sure all bus signals are
connected properly (it needs 2 separate chip enables for the two SED1520's,
each having a Control register and a Data register). My display needs a
continuous 2KHz square wave on one of the pins of the display module. No
delay routines are necessary.
The initialization is very simple:
* Write 0xAF to Control register of SED1520 #1 (Enable display)
* Write 0xAF to Control register of SED1520 #2 (Enable display)
* Write 0xC0 to Control register of SED1520 #1 (Set display start)
* Write 0xC0 to Control register of SED1520 #2 (Set display start)
Display memory is arranged into 4 pages, each spanning 61 bytes
(horizontally), by 8 bits (vertically). For columns 0-60, registers from
controller #1 must be accessed; for columns 61-121, registers from
controller #2 must be accessed.
Now to write or clear a pixel (operations are only for the active
controller):
* Write pixel Column address (0-60) to Control register (for columns 61-121,
controller #2, 61 must be subtracted from actual column).
* Write 0xB8 (pixel rows 0-7), 0xB9 (pixel rows 8-15), 0xBA (pixel rows
16-23) or 0xBB (pixel rows 24-31) to Control register to set the page
address.
* Write 0xE0 to Control register.
* Read dummy byte from Data register.
* Read display memory content from Data register.
* Modify byte to turn on or off pixels in the current column.
* Write back byte to Data register.
I have some source code in 68HC11 assembly to control the display from GCC.
Send me an e-mail if you're interested.
Good luck,
Jeroen Smaal.
My return e-mail address is invalid to avoid spam, please use
Jeroen (at) zippy.xs4all.nl
Keith Wootten
<Bin...@zippy.xs4all.nl> writes
<snipped>
>I've used a 122x32 display (with dual SED1520, bought from Conrad
>Electronics) with a 68HC11 successfully. Make sure all bus signals are
>connected properly (it needs 2 separate chip enables for the two SED1520's,
>each having a Control register and a Data register). My display needs a
>continuous 2KHz square wave on one of the pins of the display module. No
>delay routines are necessary.
I've used these too, and I can confirm that they work just as Jeroen
says with no particular problems. I got my nominal 2kHz square wave
from a 7660 inverter which I used to provide the -ve LCD bias voltage.
I have Forth source for the PSC1000A chip, but I suspect that's as much
use to you as a chocolate fireguard.
Cheers
--
Keith Wootten
Costa Constantinou
Thanks for your detailed reply. By following your start up sequence I
can finally write to my LCD's data RAM. I am using a Hitachi H8S
micro.
Many thanks,
Costa Constantinou