Identifying LCD controller by the instruction set.


New member
Hello, I am trying to identify a controller used in a 128x64 monochrome dot matrix LCD module, attached via SPI. I actually only need to know the correct instruction set, so I can write an open source driver. The part numbers for the LCD module read GV18043A and GVH18043R1, which I believe may be a Golden Vision part. I couldn't find any documentation and I got no response from Golden Vision, I found a lot of useful information on the Crystalfontz website.

The initialisation sequence in the proprietary driver almost fits the instruction set for Sitronix ST7565R or Novatek NT7534, however, there is an instruction sequence that does not make sense. The instructions [0xe1, 0xe4, 0xee] either do not appear in the documentation or appear to be used incorrectly in the driver. Most likely it is a different part with a similar instruction set.

The full initialisation sequence is as follows (assuming ST7565R instructions set):

0xa2: LCD bias set
0xa0: ADC select normal
0xc8: Common output mode reverse
0x40: Line address 0
0x2f: Power controller set: Boost = On, Regulator = On, Follow = On
0xf8: Booster ratio select mode set
0x00: Booster ratio register = 0
0x25: V0 Voltage Regulator Internal Resistor Ratio Set
0x81: Electronic volume mode set
0x22: Electronic volume register = 0x22

0xe1: Unknown (I can't find this in any documentation).
0xe4: Unknown (NT7534 datasheet lists this as Oscillation Frequency Select).
0xee: Unknown (ST7565R datasheet lists this as Read/Modify/Write END, but it is not preceded by 0xe0 here).

0xa4: Display all points = Off
0xa6: Display Normal/Reverse = Normal
0xaf: Display on

I don't know a great deal about LCDs, but this looks like a sane initialisation sequence based on the datasheets listed above, only the sequence [0xe1, 0xe4, 0xee] does not fit the documentation.

Does anyone know of an LCD controller where the instruction sequence [0xe1, 0xe4, 0xee] would make sense in the context shown above?


Epson S1D15705 documentation lists 0xe1 as Power Save Reset and 0xe4 as n-Line Reversal Drive Reset, however, this controller does not appear to have instruction 0xf8.
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New member
I went through the command code listings and reviewed every controller chip similar to the chips referenced in the forum post, plus many others - none have the 0xe1 or 0xe4 commands. I did not have access to the Epson SID15705. I limited my search to controllers used in graphic LCDs.


New member
Thank you for taking the time, I wasn't sure if I was missing something obvious. I tried skipping those commands when initialising the display and it works with no noticeable difference. Perhaps the proprietary driver was compiled from generic code, or had typos in the source.