LCD Driver Module for the front panel, BL and -VE link

[Pierre Gaston]

Hi,

The documentation on https://rc2014.co.uk/modules/lcd-driver-module/ is slightly confusing, on the first paragraph it says:

" You will also need to solder a link across the BL/VCC jumpers for the backlight "

Later down it says:

"The 3 pin header next to the 2×10 header needs a link soldering across the central BL pin and the -VE pin. (For a 24064 screen, the outer pins of VCC and Ground should be connected). Note that on the v1.1 revision of the PCB the silkscreen indiacating that BL and VCC should be linked is wrong. From v1.2 onwards this is corrected to show BL and -VE need to be linked for an external display." 

So I assume the first paragraph is also on version 1.1? and that I should link BL and -VE?

What about "the outer pins of VCC and Ground should be connected", is this just a consequence of linking  BL and -VE?

Thanks

Pierre

[Spencer Owen]

Hi Pierre,

Ah, sorry for the confusion there. The line in the first paragraph you quoted was wrong. I should have updated that when the v1.2 boards came out, but must have missed it. I have fixed that now so that it reads "You will also need to solder a link across the BL/-VE jumpers for the backlight"

There aren't many v1.1 boards out there in the wild, and none have gone out since July 2024, so I assume that by now those have all been assembled. Maybe I should remove any reference to the v1.1 to avoid further confusion.

For a bit more context about that jumper and why it is there, the 2x10 header was originally designed for the 24064 display.  It was almost exactly what I needed to connect to a 4x20 display, however, there was no backlight pin and no spare that could be used. However, Vcc went to both pin 3 and pin 9. So I routed pin 9 to the jumper header so that it can either be connected to the BL signal for a 4x20 display *or* the Vcc for a 24064 display.

Hope that helps

Spencer

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[Pierre Gaston]

Thanks Spencer, 

I do think I would have  got  that if I paid attention to 24064 vs 2004 screen, for some reason I initially linked VCC to -Ve ...and  that did gave me  backlight

then Vcc to BL and now BL to -Ve ... after following the circuit I realised that the voltage  on BL was quite low and that the screen gets dark rather quickly.

Now I need to check why that I don't get text after running the basic example :D

Pierre

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