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UC1701 128x64 monochrome LCD

Fri Feb 23, 2018 7:08 pm

I just released a C library for drawing text and graphics on this LCD. I chose this LCD because it looked like a good replacement for the lower quality Nokia 5110's in circulation. The qualities I was looking for were:

1) Low cost
2) Transflective (visible in sunlight without the backlight on)
3) Low power
4) Higher resolution (than the Nokia 5110).

The UC1701 (JLX12864G product ID) I found fit the bill. The only problem was that the power consumption was much more than expected. This LCD controller is advertised as being extremely low power. It is, but the PCB I received had several power issues that I had to manually solve. There is a 3.3V and 5V version of the PCB (mine is marked as JLX12864G). The 5V version includes a 3.3v linear regulator. The regulator doesn't stop it from working when given 3.3V, but it does waste a little energy. My board started out at 2.25mA (@3.3v) when active and 2.0mA when sleeping. This is quite a bit different from the current draw claimed in the UC1701 datasheet. I removed the linear regulator, but that only reduced the current a small amount. I then discovered that my PCB included a Chinese character font EPROM (U1). This chip when idle was drawing nearly 2mA! I removed it and now the LCD draws nearly 0 when idle and 276uA when active. The backlight (with included 120 ohm resistor) draws about 4.8mA. A good improvement over the Nokia 5110 (400uA active current).

Here's my code:

The fastest code is none at all :)

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