Tag Archives: raspberry pi

Raspberry PI I2C and SPI

I2C

https://www.balena.io/docs/learn/develop/hardware/i2c-and-spi/#i2c

"scripts": {
  "preinstall": "bash deps.sh",
  "start": "modprobe i2c-dev && node app.js"
}

CMD modprobe i2c-dev && python /app/demo.py

SPI

https://www.balena.io/docs/learn/develop/hardware/i2c-and-spi/#spi

dtparam=spi=on

Raspberry PI 3 bluetooth, serial & UART settings

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Raspberry PI 3 bluetooth, serial & UART settings

https://www.balena.io/docs/reference/OS/advanced/

The BCM2837 on the Raspberry Pi3 has 2 UARTs (as did its predecessors), however to support the Bluetooth functionality the fully featured PL011 UART was moved from the header pins to the Bluetooth chip and the mini UART made available on header pins 8 & 10.

specifically

The device /dev/ttyAMA0 previously used to access the UART now connects to Bluetooth.
The mini UART is now available on /dev/ttyS0 but disabled by default.
The mini UART is a secondary low throughput UART intended to be used as a console.

To enable the mini UART an entry should be added to config.txt as follows:

enable_uart=1

PI B rev 2 v PI ZERO CPUs

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There is actually very little difference between the CPUs on a PI B rev 2 and on a PI ZERO

PI B rev 2

root@9a98b74:~# cat /proc/cpuinfo
processor : 0
model name : ARMv6-compatible processor rev 7 (v6l)
BogoMIPS : 697.95
Features : half thumb fastmult vfp edsp java tls 

CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xb76
CPU revision : 7

Hardware : BCM2835
Revision : 000d
Serial : 000000007175d124
Model : Raspberry Pi Model B Rev 2

PI ZERO

root@743af1a:~# cat /proc/cpuinfo
processor : 0
model name : ARMv6-compatible processor rev 7 (v6l)
BogoMIPS : 997.08
Features : half thumb fastmult vfp edsp java tls 

CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xb76
CPU revision : 7

Hardware : BCM2835
Revision : 9000c1
Serial : 000000006597f274
Model : Raspberry Pi Zero W Rev 1.1