Raspberry Pi 3 and Zero W Serial Port Usage
Created 19/03/2016 | Configure the serial port on Raspberry Pi 3 and Raspberry Pi Zero W with a Serial Pi
You can use the Serial Pi Plus and Serial Pi Zero with your Raspberry Pi 3 or Raspberry Pi Zero W if you disable the built in Bluetooth modem as this is mapped to the hardware UART by default and the "mini uart" on the Raspberry Pi 3 and Pi Zero W GPIO pins is not stable when the processor is under load and the baud rate changes.
For Raspbian Jessie releases after 18th March 2016
There is now a device tree file called pi3-miniuart-bt which makes the Raspberry Pi disable the Bluetooth module and map pl011 UART on pins 14 and 15 as before.
Step 1 - Install Raspbian Jessie onto a SD card and boot the Pi when connected to a network
Login via terminal or desktop and shell
Configure the system with:
Expand filesystem and enable serial on advanced page, exit and reboot.
Update the system with:
sudo apt-get update
sudo apt-get upgrade
Step 2: Device Tree settings as below:
Add device tree to /boot/config.txt to disable the bluetooth module.
sudo nano /boot/config.txt
Add at the end of the file
Exit the editor saving your changes and then:
Enabling the Serial Console Rasbian Jessie after 18th March 2016 release
To enable the serial console, you need to edit the /boot/cmdline.txt file
sudo nano /boot/cmdline.txt
Change the file to the following:
dwc_otg.lpm_enable=0 console=tty1 console=serial0,115200 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
Exit and save your changes
With the serial console enabled you should now have the boot commands and login prompt when connected at 115200 baud.