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Its many years since I used a graphics display module - a Displaytech one if I recall correctly. I am now trying to use a 64128K. As is usually the case when you visit, or revisit, a new device, its just a case of getting it going, then it all builds from there. I have connected the device to a 5V microcontroller (it happens to be an 8051 core). I'm using the serial mode i.e. 5 control lines. I've used a 5V-3.3V buffer (is 3.3 V too great ?) to control the lines. I have connected 4 x 1uF caps as per the data sheet for a x4 voltage gain and also 5 x 1uF capacitors to pins V0->V4  I understand that it is possible to use the device without either an external oscillator or any backlight power or any external power on the Vout pin 16. I have tried the sample code for the serial application - which is written in 8051 assembler; I've also tried writing my own code with what I perceive are the correct commands..The thing is not doing anything despite the signals to the control lines  working seemingly as they should. All pins cap3p, cap1n, cap1p, cap2p, cap2n and also V0->V4 have approximately 2V stable DC on them. I vaguely recall that all these pins should have voltage gain on them but I'm not seeing anything. What voltage should I be seeing approximately? I'm guessing that perhaps an internal oscillator isn't working. Clearly its just the old cliche of "I've fogotten to press button 'X'" ..What am I doing wrong ? Can anyone help ?




jimmy_seacomp's picture
December 7, 2020

Hi John,

Thank you for contacting us through our forum. Our 64128K product page,, provides the schematic and sample code. If you follow this the unit should work. If you are following this and still having an issue please help provide additional information for what you are doing so we can try and help troubleshoot for you.

Thank you,