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STM32F722 +LCD160CR v1.1, WBUS pins

Posted: Wed Aug 14, 2019 9:52 pm
by iiigor
Dear users,

I am arduino user (hobbyist), but I use&like python so I would like to try micropython. I bought pyboard-D STM32F722 + LCD160CR v1.1.

How could I connect my uPC with LCD? I thought following:
1) STM32F722 - has 2x WBUS
2) LCD160CR v1.1 - has 2x WBUS
3) I soldered headers at X and Y pins LCD160CR board
So I connected both WBUS pairs, it match together :). And when I test headers at LCD160CR board, X - pins works, but Y not. I would like to use X pins for LCD, and Y for pressure/temperature sensors.

Please, is somewhere schematic for LCD160CR v1.1, with W-BUS? (everywhere is only version 1.0, without W-BUS). Probably I don't understand it, by my multi-meter shows short circuit between X1-Y1, X2-Y2 at LCD board... Is it correct? (when you look at v10 version, there is also short circuit, right?).

Sorry for really silly question, but it is possible to use WBUS to "transfer" both X and Y pins from uPC -> LCD board?
Thanks, BR, ii

Re: STM32F722 +LCD160CR v1.1, WBUS pins

Posted: Thu Aug 15, 2019 1:23 pm
by jimmo

WBUS is a pyboard-d thing only -- it refers to the two connectors on the bottom of the pyboard-d (that connect it to things like the wbus-mmc, wbus-dip28, etc).

I think what you're describing when you say WBUS is actually the X and Y "positions" used on both pyboard 1.x and pyboard-d. Each of these include an I2C, SPI and UART. The idea being that on a pyboard 1.x, you can put a "skin" (like the LCD160CR) in either the X or Y position.

The LCD160CR design seems kind of strange at first glance (as you've noticed the "short circuit" across the sides), but it makes sense when you consider that it is designed to be "side-mounted" to a pyboard 1.x.

So consider the four ways of connecting a LCD160CR to a pyboard 1.x:
- On top, X position
- On top, (rotated 180 degrees) Y position
- Left hand side
- Right hand side

The inner set of pins are only for the first two options, the outer set are only for the second two.

The complication is that the LCD160CR needs both SPI and I2C. But if you look at the layout of the pyboard, for the 'X' position, the SPI is on the left, and the I2C is on the right. And the other way around for the 'Y' position. So in the side-mounted configuration, you have to use a combination of the X SPI and Y I2C (or on the other side, the Y SPI and X I2C).

So the pins on the LCD160CR are labeled such that when it's side-mounted to a pyboard, the labelling on the outer pins makes sense.

Anyway, in your case, you'd be wiring it directly to your pybd. So the easiest thing is to use the inner pins (labelled X1-12 etc) and connect them to either X1-12 (or Y1-12) on the pybd. Or use the outer pins, but pretend the 'Y' ones actually say 'X'.

Sorry hope that makes sense...easier to explain in person I imagine, but hopefully thinking about the intention of the design will make it more obvious (especially if you look at the pin layout of the pyboard 1.x -- ... v1_1-E.jpg ).

Something to be aware of too - on the pyboard-d, you have to enable power to the X and Y connections using

Code: Select all

Please let me know if I can explain any of that in more detail.

Re: STM32F722 +LCD160CR v1.1, WBUS pins

Posted: Thu Aug 15, 2019 5:25 pm
by pythoncoder
@jimmo In the OP @iiigor has got a Pyboard D. The LCD160CR V1.1 has wbus connectors on it and the Pyboard D can plug into it directly. I have tested it in this mode and it works fine. The supplied program works.

Re: STM32F722 +LCD160CR v1.1, WBUS pins

Posted: Fri Aug 16, 2019 1:10 am
by rcolistete
LCD160CR can work with only I2C, AFAIK and tested.

Re: STM32F722 +LCD160CR v1.1, WBUS pins

Posted: Fri Aug 16, 2019 3:19 am
by jimmo
Ah cool thanks for letting me know. I was wondering what the v1.1 difference was!

Sorry about the incorrect info! Hopefully there's some useful stuff in there though that can help you. Maybe the EN_3V3 is what you need?

I'll try and find out about getting the v1.1 schematic uploaded.