These are chat archives for nebrius/raspi-io

20th
Jul 2016
ajfisher
@ajfisher
Jul 20 2016 10:02
@nebrius so to debug this a bit more. Confirmed that my rpi has a baudrate of 100000
I'm not sure what's causing it but I suspect it's contention on the I2C bus. I wonder if we need to add some error handling at a lower level
I'm not that familiar with Raspi-io to quite know where to go hunting though
ajfisher
@ajfisher
Jul 20 2016 10:12

Specifically the error I'm getting is this:

{ Error: EIO, Input/OUtput error at Error (native) errno: 5, code: 'EIO', syscall: 'readI2cBlock' }

Bryan Hughes
@nebrius
Jul 20 2016 17:03
@ajfisher that will be @fivdi’s domain, as raspi-io (specifically raspi-i2c) is basically a wrapper around i2c-bus
also, I don’t know if this is an option for your build, but can you try using DotStar’s instead of NeoPixels? Although not supported by raspi-io specifically, they can be driven by SPI directly and you could eliminate the backpack entirely
Brian Cooke
@fivdi
Jul 20 2016 20:27

@ajfisher please post the complete contents of /boot/config.txt

It's very unlikely that there's contention accessing the I2C bus, irrespective
of the number of devices being accessed. Under the covers each i2c-bus
method is an atomic transactions. This atomicity is provided by the Linux kernel.

Also, it's possible to measure distance with a HC-SR04 on the Pi without a backpack. See https://github.com/fivdi/pigpio#measure-distance-with-a-hc-sr04-ultrasonic-sensor