Does installing the Mini PiTFT kernel module block the whole SPI bus?

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jblackburn
 
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Does installing the Mini PiTFT kernel module block the whole SPI bus?

Post by jblackburn »

I have the 1.14" Mini PiTFT running the console via the kernel module described in the Adafruit guide linked below. I'm also trying to read a BMP388 sensor in SPI mode using Adafruit's SPI example from their tutorial, but I'm getting the error

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OSError: /dev/spidev0.0 does not exist
and when I run

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ls /dev/spi*
to check the SPI bus exists, I get

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ls: cannot access '/dev/spi*': No such file or directory
indicating it does not.
Does the kernel module in the tutorial below block the entire SPI bus? If so, is there another SPI bus I could use to interface with sensors? Or is there another way to get the console on the display without blocking the SPI bus?


https://learn.adafruit.com/adafruit-min ... le-install

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adafruit_support_mike
 
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Re: Does installing the Mini PiTFT kernel module block the whole SPI bus?

Post by adafruit_support_mike »

jblackburn wrote: Tue Sep 20, 2022 6:01 pm Does the kernel module in the tutorial below block the entire SPI bus?
Yes. There's no way to manage synchronization of the CS pins between the kernel driving the TFT and user code trying to talk to another device.
jblackburn wrote: Tue Sep 20, 2022 6:01 pm If so, is there another SPI bus I could use to interface with sensors?
The RasPi only has one hardware SPI bus, but SPi isn't hard to bit-bang.

If you're using our CircuitPython library for the BMP388, you should be able to create an SPI device with any of the RasPi's free GPIO pins:

https://docs.circuitpython.org/projects ... bus-device

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