Summer of FPGA: Using the Mikroe LCD Click Mini on the Ultra96-V2 - Part One

RE: Summer of FPGA: Using the Mikroe LCD Click Mini on the Ultra96-V2 - Part One

Andrew J — Sat, 18 Sep 2021 18:25:02 GMT

Ok....Trying different LCD initialisations, not conforming to the LCD driver chip on the LCD data sheet, but the Hitachi HD44780 which is the granddaddy of them all, I can actually see characters properly. So it isn't a contrast issue, but an initialisation one. I'm not sure exactly what the correct startup is yet as following that given in the Hitachi's data sheet leaves me with faint characters but missing out a step of the initialisation given there, leaves me with a readable display. In any case, following the initialisation given by the LCD's data sheet leaves me with a misbehaving display.

I can at least work it out from here!

RE: Summer of FPGA: Using the Mikroe LCD Click Mini on the Ultra96-V2 - Part One

Andrew J — Sat, 18 Sep 2021 16:06:25 GMT

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Hi Bryan,

do you know of anyone who has managed to get the LCD Mini Click working via the Click Mezzanine such that they can actually see the display?

I've managed to get it working but for a long time I thought it wasn't: the contrast on the letters is so poor they are barely visible - certainly not demonstrable! Unfortunately, the Click Mezzanine doesn't allow access to the DigiPot on the LCD Mini Click board to change it. I'm wondering if I'm doing something else wrong or if there is some underhand way of getting to that DigitPot without bodging wires onto it and potentially damaging it. According to the data sheet for the DigiPot it should start up at mid-scale but that's obviously not high low enough. It seems strange it's sold as a starter kit but isn't actually useable!

RE: Summer of FPGA: Using the Mikroe LCD Click Mini on the Ultra96-V2 - Part One

jc2048 — Sat, 04 Sep 2021 13:46:12 GMT

If you wanted to experiment with the Digi-Pot, I can think of two things you could try (neither very elegant):

1) solid-core wire from the AN pin of the LCD Click Mini plugged in to the CS socket on the other header, or

2) lift pins 1, 2 ,and 3 of the MCP4161 and wire them instead to the GPIO expander. You'd then have to emulate SPI with a GPIO expander on SPI. Messy, but it's not like you need to change the contrast on an LCD panel very much.

I suppose a third option would be to ditch the sophistication of the Digi-Pot and use an ordinary preset pot, with a screwdriver to adjust it.

RE: Summer of FPGA: Using the Mikroe LCD Click Mini on the Ultra96-V2 - Part One

bhfletcher — Fri, 03 Sep 2021 19:44:22 GMT

I'm very excited to see your progress, here! Out of curiosity, why did you decide to go the PL route rather than use the existing PS pinout?

Bryan