Breakout Garden spi devices

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1

Can I use 2 spi displays with the breakout garden if so how can I do it.
Thanks

2

Have a look see here
https://www.raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md

MOSI    Pin-19  GPIO 10
MISO    Pin-21  GPIO 9
SCLK    Pin-23  GPIO 11 
GND     Pin-25 
        Pin-24  CE0
CS      Pin-26  CE1

There are two slots so I would assume its doable. It appears to me its done via the CS pin on the breakout, which I think means Chip Select? On the mini breakout garden SPI slot that goes to GPIO 7, CE1. CE I’m guessing is Chip Enable. I’m far from any kind of expert on this, just so you know. ;)
I think that corresponds to the front slot on the i2c SPI Breakout Garden Hat. On the rear SPI slot I’m thinking the CS pin goes to GPIO 8 CE0
I used an Ohm meter to check what pin went where on my Mini. The one marked GPIO is I believe used for the backlight on the display.
So to make a long story short, its done via your python code.

In the example code for the display I tired out it has stuff like this
cs=ST7789.BG_SPI_CS_FRONT, # BG_SPI_CSB_BACK or BG_SPI_CS_FRONT
and
backlight=19, # 18 for back BG slot, 19 for front BG slot
You just have to edit it for the slot its in.

3

Found this on the product page

The top/back slot (closest to the Breakout Garden logo) uses chip select 0 (BCM 8) and BCM 18 for the GPIO (used for things like LCD backlights) pin.
The bottom/front slot uses chip select 1 (BCM 7) and BCM 19 for the GPIO pin.

So I guess I guessed right, lol.

4

Got i working of sorts by changing the port and backlight numbers but alas lots of flicker between displays . Hopefully I can find a software fix before I unretire my soldering bolt (that will work).
Thanks.

5

I’m no python expert but if you post your code I might happen on something to help with the flickering. Past your code between two ` and it will retain the indents etc. On a US keyboard its the key under the esc with a ~ on it.

6

If your not already, you’ll likely have to do something like
disp1 = ST7735.ST7735(
disp2 = ST7789.ST7789(
So you can use separate blocks of code for each display. Those are just examples based on the two LCD Display breakouts Pimoroni sell. 35 is the 0.96 inch and 89 is the 1.3 inch

7

Thanks for the help got it working ok (no flicker) . My new problem is how to display a photo I cant get the cat example to work any ideas.
Thanks

8

I cant get the cat example to work any ideas.

Does it give you an error when you try to run it? Which display do you have, and which slot is it in on the Breakout Garden?

9

I have tried both slots alas no error message but also no jpg on the st7735 .It works on all the other examples.
Thanks

10

That’s odd. Can you post the exact command you’re using to run the script?

11

I have tried
python3 image.py
python image.py
with and without sudo
all the other examples work.

12

Ah, I’m pretty certain that if you do that it should print a message about how the script should be used: you need to type python3 image.py followed by the name of the image you want to show. To show the example cat photo you would type python3 image.py cat.jpg.

1 Like
13

Thanks I would never have thought of that.
Cheers.