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Display Area Setup

I am working with the S128240C display in 4 - line serial mode. When I first ran the display my data was rotated 180 degrees, that is, the data read correctly if rotated so the cable was pointing up. I have my display board designed with the display cable pointing down. I experimented with the scan direction and line and column number reversal and managed to get the display turned around. However I had to give the column addressing an offset of 5 to get the lines to start in the correct column. Now I have a unusable column on the right-hand side of the display area. What have I done wrong or missed in the initialization?

I am somewhat disappointed with the contrast of the display. I have managed, using VOLCTRL, to get a reasonable shade of gray for my characters. I also adjusted the duty cycle, booster efficiency, bias ratio and oscillator frequency but have not been able to increase the contrast. What other steps are required to increase the cintrast?

I am attaching schematics, code and a photograph of the display in operation.

Feedback would be appreciated.


dtechsupport's picture
July 9, 2009

Please see below from the factory:

- Please have customer to amend their program as below.
wcom(0xca,0); //display control
wcom(0x00,1); //cld=0
wcom(0x23,1); //set duty=1/144
wcom(0x00,1); //set fr value
wcom(0xbc,0); //data scan direction
wcom(0x03,1); //seg254~seg0,com160~com0
wcom(0x01,1); //rgb arrangement
wcom(0x04,1); //32gray scale 3b3p dither mode
wcom(0x15,0); //column address set
wcom(0x05,1); //start column=5
wcom(0x54,1); //end column=84

- On the customer schematic page 2, please have the J2-4 to J2-11 connected to Vdd. In the customer programme, please clear the DDRAM data column0~column84 and line0~line159 before sending Display data to the DDRAM.