WG12864A - initialization issue

[marmur99]

Hi,

I have got WG12864A-TFN-T#H and a problem with its initialization. I have followed **broken link removed** 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

 

[limnesh]

I'm facing the same prob with WG12864A interfaced with an 89S52.
Was your problem solved???

Attaching my asm code...

 

[marmur99]

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]

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 - - -


My current pin Config

 

[limnesh]

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...