Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

WG12864A - initialization issue

Status
Not open for further replies.

marmur99

Newbie level 2
Joined
May 2, 2011
Messages
2
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Location
USA
Activity points
1,302
Hi,

I have got WG12864A-TFN-T#H and a problem with its initialization. I have followed this document to connect the device to the system. I am pretty sure I have done that well and I cannot see any electrical problems. Unless I've been working on it too long to see some obvious mistake.
Anyway, the problem is that when I read back status, it has always value 0xA0, which according to spec means BUSY and LCD_OFF. Even if I ignore the status, there is nothing on the LCD. I also tried filling the space with 0xFF to see enything - no success.

  • Power supply is 5V
  • Vo connect through R-divider between VDD and Vout
  • Reset cycle is done by CPU (low state interval is about 100us)
Please find attached source file that I am using to initialize the device.

I guess three options are likely here:
  • Broken LCD
  • software issue - lack of proper initialization procedure or something
  • hardware issue - this is least likely as I checked everything several times. If I want to send something to LCD, it is visible on its connector. The value 0xA0 really comes from the LCD - checked that with a multimetter.

Any help very appreciated!

marmur99
 

Attachments


limnesh

Newbie level 3
Joined
Jul 16, 2012
Messages
3
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,293
I'm facing the same prob with WG12864A interfaced with an 89S52.
Was your problem solved???

Attaching my asm code...
 

Attachments


marmur99

Newbie level 2
Joined
May 2, 2011
Messages
2
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Location
USA
Activity points
1,302
Hi,

in my case that was a h/w issue. I forgot some details, R-divider that polarizes Vo should be connected between other points than Vdd and Vout. It was not clearly said in the datasheet but I think I found someone's design and realized that this was it.
If you observe exactly the same behavior, have a look at the Vo pin.

Mariusz
 

limnesh

Newbie level 3
Joined
Jul 16, 2012
Messages
3
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,293
View attachment image.bmp
Hi marmur,
VDD, VO, VEE connected as above in my circuit. Is it alright??? Can u please provide me the link to the correct wiring strategy if available?
regards,
--lim--

- - - Updated - - -

image.jpg
My current pin Config
 
Last edited:

limnesh

Newbie level 3
Joined
Jul 16, 2012
Messages
3
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,293
Thanks murmur for ur reply...
My problem was solved. It was the same VDD-V0-VEE issue. Rewired it with some resistors 25K, 1K and the prob was solved...

Thanks for ur support...
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top