Beginners • Re: Can someone explain how to wire 2 SPI devices?

Why they can't be connected together?

Or you don't want them to be connected together?

First which RPI do you have?

Is it because you are using two different applications ? If not I don't see a problem with that!

Did you read the READMe in /boot/overlays

I assume.....GPIO header.

First, I hope you have a typo ... 5 volts is lethal for your RPI. (you must be sure that a perifeic output does not go beyond 3.3v ... even if the periferal has 5v supply). Without further info, on cannot know.
According to your schematic, you can wire together MOSI, MISO and CLCK together, BUT chipselect *must* be different. Else, periferal coud send data at the sme time, on the same qire, which would lead to a huge mess.

A description of how SPI works is in wikipedia https://en.wikipedia.org/wiki/Serial_Pe ... _Interface

I do not want to solder two jumper wires into one to create a fork and share a GPIO pin. Is that what you are asking?

You can, as danjperron showed, use solderless boards...

I am using the RPI zero v1.1 but I thought all the GPIO pinouts were the same on Pi's? Is that not the case?

Yes

Two different applications of what? I am using Thonny to program the devices, is that what you mean?

If two applications run simultaneously, nothing protects from the situation where two SPI chips are simultaneous selected, leading to a huge mess.

- I did indeed mean 5V. The Waveshare display I am using has a voltage regulator and accepts 3.3v/5v as per their documentation. Hooking that up to one of the compatible 5v ouput pins on the pi header it works well, so I would not describe it as lethal. Maybe bad practice?

- I read over that wiki article and a lot of it made sense but I couldn't find anywhere in there how to wire two different SPI devices up to the same Raspberry pi header and, as the title implies, this is really what I am looking for here.

- A breadboard is not an option within the confides of my project enclosure. It would be ideal if I could connect both of the SPI devices up to the same Raspberry pi header, directly.

- I'm still not sure what you mean by two different applications, but I will take another guess... I am using the Waveshare as a primary display (no script/application controlling it) and then need to wire the RFID reader in it's own script (launched from the desktop environment) to read RFID tags with authentication.

Statistics: Posted by Smallfry341 — Wed Feb 21, 2024 1:22 am

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