Frustration over use of SPi terms

I have a small number of small LCD screens and every bloody one of them uses unique naming for the pins!!!

For example your 1.54" colour IPS LCD has printed on it (see the photo)

  1. 3-5V
  2. CS
  3. SCK
  4. COPI
  5. DC
  6. BL
  7. GND

And here is how you document the use of those pins for a Raspberry Pi

Here's which pins to connect between your LCD breakout and your Pi's GPIO (note that it's BCM pin numbering):

    3-5V to any 5V or 3V pin
    CS to BCM 7
    SCK to BCM 11
    **MOSI** to BCM 10
    DC to BCM 9
    BL to BCM 19
    GND to any ground pin

You can of course use other pins with your LCD Breakout, but you'll have to change them accordingly when you instantiate the display in your code.

Note how you’ve completely ignored the printing on the product pic and referred to MOSI, whereas the product has COPI. It’s only through deduction that I assume they’re the same thing. Every screen uses a different (UNEXPLAINED!) acronym for MOSI (and sometimes other pins.

Please do better

/end of grumpy note

In the past, things were easier: there was MOSI and MISO (master-out - slave-in, master-in - slave-out). But people are trying to move to a more inclusive speech, but there is not yet a consensus on how these terms are replaced. You will find TX and RX, DO and DI, but also other terms. And you will find engineers replacing the terms on the PCB and technical writers not knowing about that this has happened.

Independent of this, the name of the clock-pin has never been a standard, you will find SCK, SCLK, CLK and possibly other terms.

This is all part of real life.

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Unless you’re proposing ESP or a Babel fish, then it’s the job of whoever’s chosen to opine, write or blog about some tech, to understand the range of needs of their audience and explain the fuck out of the confusion. That is literally what they implicitly sign up to do if they choose to write. Anything else is just sowing more confusion. The Internet is awash with it. To do better is to explain everything a user/reader is likely to need to know, INCLUDING confusing naming conventions - even if this is a (one hop) link to a page that JUST covers the naming confusion. It’s not good enough to call it ‘real life’, as if that’s a sufficient explanation and implying users should get used to it/man-up. The writer’s job is to explain, so EXPLAIN!

The documentation in question pre-dates the changing acronyms by a considerable margin and while yes, in an ideal world every bit of documentation would get insta-updated with every silk-screening tweak that rarely happens.

It’s not ideal but at the same time, the MOSI → COPI change is relatively recent and yet at the same time extensively discussed online (a simple search of “SPI COPI” throws up a ton of documentation - and more than a few reddit threads railing against the change).

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I’ve done a bit of digging and it looks like the silk for this breakout has said MOSI since 2021. I’ve added a note about the previous labelling and I’ll see if I can grab a new one and update the photo when I get a moment, which should hopefully make things less confusing.

Are there other products I should be looking at where there’s a discrepancy with the pin labelling?