Friday, 12 August 2011

Arbitrary Doodle page

(It's what it says it is.)

Sunday, 7 August 2011

GLCD identification follow-up

I'm posting bigger pictures of the units along with the process of how I identified them. Part of this journey is my impatience*, and part of it is me just being dumb**, if you can own up to either of these cases, please read on; else go blame it on a Muslim.

1st unit I got as a gift, it's green, and has probably not blown up. No datasheet, but identifies in my mind as something with Toshiba shipset, on account most chips bear the Toshiba name eatched or printed on them, and a clue in the silkscreen (top right) T12864 or 12864T. The next give-away is in the sticker in middle foreground of the picture, it says MGLS12864T. The way it's written on the chip 3 times over told me it must be identifying the chipset, and not the Toshiba-ness, so that warmed it up for me, I was initially lost on the pinout, hence it may have been damaged in my impatience already.

1 = Ground
2 = Ground
3 = +5V
4 = contrast (wiper of a 10kohm preset connected between Ground and +5V)
5 = negative acting (negative logic) WRITE
6 = READ (you can wire the /WR and /RD up using an inverting gate I expect)
7 = Enable - still not sure, but this appears to be the clock?
8 = Command /Data mode
9 = Reset pin, you might tie this to pin1 on your CPU, bit I prefer a R/C network
10 ... 17 = data0..7
18= font size, I tied this line to logic 1

The chipset is called 6963 which will net you the datasheet

2nd unit I bought, is blue but did not pay attention to the link to a datasheet. 
When I forgot** where I got the unit from I was in trouble. And even if I did I would not have worked it out anyway, so here is some help. The unit looks like this closer up from behind , and front
Model is a 12864BG ,at this point it becomes clear that 12864 stands for 128x64 pixels, using a GB suffix in a google finds you a datasheet, this baby has 20 pins.
It's an LED backlit unit, the backlight wants between 3 and around 4V, I use a 100Ohm to the +5V rail, you can probably use less. Unfortunately I have blown up the LCD drive on this unit, which is the SMT chip on the top-left.
Pinout for GLCD

1= Ground
2= +5V
3= Contrast - wiper of 10Kohm trimmer, but this time connect the one end to VO (pin 18), other end must connect to ground I suspect
4= RS ?
5= READ / WRITE (write is negative acting)
6= Enable or clock the command into LCD
7..14 = data 0..7
15 = Chipsel1 (1st half screen)
16 = Chipsel2 (second half screen)
17 = Reset pin
18 = This is an output, connect to one end of the10K trimmer
19 = Led + (100ohm 3watt resistor to the 5v line)
20 = Led ground

The only thing left is to upload the datasheets, but they are copyright I suspect, hold that thought, maybe some fresh links.

Legend :
** = I am dumb
* = I'm impatient