I salvaged an Optrex DMF5001NY-LY-ATE-BBN 160x128 pixel graphic LCD. It uses T6963C so shouldnt be anything special about that.
Otherwise the schematic and display is clear to use but the LCD drive supply voltage is a big mystery. What should the voltage be? The display does not seem to have a built in charge pump.
In the datasheet it says that logic supply voltage should be -0,3V - 7V (VCC - VSS). This is clear. 5V from GND to VCC and it works.
But the LCD drive supply voltage is a mystery. It is stated as -0,3V - 30V (VCC - VEE). So if VCC is 5V, should VEE be 4,7V - 35V??? Or should it be negative -5,3V - -25V? This is the part I do not understand and would need help with.
From your datasheet 4.2.Example of Power Supply
VCC = 5V
VEE = -20V
adjust the potentiometer for best contrast.
measure the actual voltage on the pot.
I suspect that it will be about halfway. i.e. -7.5V
Connect #3 (VCC) to 5V and #2 (VSS) to 0V
I suspect that pin #4 (VEE) on your module has generated a suitable -ve voltage.
Thanks for the reply! I tried but get nothing on screen. Maybe pinout is wrong?
In u8glib the pinout for T6963 is: D0..D7, cs, a0, wr, rd, reset
On my screen I have: D0...D7, rd, wr, ce, c/d, halt, reset
Halt is not included in the library. I have connected it HIGH to enable clock. a0 and cs corresponds to ce and c/d. I have tried to connect both ce - cs and c/d - a0 and ce - a0 and c/d - cs but screen does not work.
I have left VEE disconnected, connected it to a pot (vee - vadj - vcc) and also connected it to GND and VCC. Nothing works.
LCD is blank wothout any life signs. When pot is connected, turning it does not make the screen go brighter or darker. It is just every time the same.
Well, it was not difficult to do. And you did not get a -ve voltage.
So it looks as if you will have to provide your own voltages.
Most 128x64 KS0108 / ST7920 / T6963C modules provide suitable voltages on the pcb. You just use a pot to adjust for contrast.
Many modern COG controllers generate all the voltages on the COG chip. And even allow you to select the appropriate values from on-chip ladder networks via software registers.
However T6963C is an elderly design.
I found in my drawers a step-up + charge pump circuit. It gives out +12v and -12V from 5-12V input. Now when I connect power, there is a line getting black for a small ammount of time.
NusNus:
I found in my drawers a step-up + charge pump circuit. It gives out +12v and -12V from 5-12V input.
That will be a MAX232 or variant like the MAX233. RS232 interface. Certainly will do the job.
The ICL7660 is the basic - original - charge pump IC but there are so many charge pump ICs nowadays (and possibly already included in the ATmega328 for its EEPROM) that it took me considerable time to jog my memory and find the name of the ICL7660. There are other derivatives on the Aliexpress item page I cited that operate at higher voltages FWIW.
