You need to disable serial console on your Pi and enable UART with
sudo raspi-config
Select Advanced Options/Serial and disable the serial login shell or Interface Options/Serial and disable the serial login shell but enable the hardware(UART)
Then you need to sudo reboot
If you are still not receiving messages on your receiver HAT in RPI mode from your RF-Craft HAT in EXT transmitter mode with a NODE_ID of 1 ie (1,1), you may also have to follow the below instructions from Frederick Vandenbosch
It seems the recently launched Raspberry Pi 3 behaves differently with regards to the UART interface on the GPIO header. In this guide I go through the steps I took to get the UART working for serial console or HAT communication.
I am assuming you are using a recent Raspbian Jessie image (2016-03-18 or more recent) on Raspberry Pi 3, that the file system has been expanded and that enough space is left for the software updates to be installed.
Let’s go!
Make sure you are on the internet. If in doubt ping google.com and if you are receiving 64 bytes on each ping you're ok. ctrl-c to stop the pings (they stop themselves after 10). Be aware depending on speed of your internet this can take a while ;)
The first thing you’ll probably need to do is to ensure all software components are up-to-date. Update the repository and upgrade the installed packages:
pi@raspberrypi:~ $ sudo apt-get update && sudo apt-get upgrade -y
Update the firmware:
pi@raspberrypi:~ $ sudo rpi-update
Reboot to apply the changes:
pi@raspberrypi:~ $ sudo reboot
A new property has been introduced to enable the UART on the Pi. This property will put the core frequency to a minimum, ensuring stability. It’s possible to put the core frequency to maximum as well, assuming the power supply is powerful enough and the Pi 3 is properly cooled (heatsink!).
Enabling UART with minimum core frequency:
pi@raspberrypi:~ $ sudo nano /boot/config.txt
The file can be found on the SD card and accessed that way or when the Pi is booted and running
# Enable UART
enable_uart=1
More information on this newly introduced property can be found here
To disable the console, edit the following file as follows:
pi@raspberrypi:~ $ sudo nano /boot/cmdline.txt
As before the file can be found on the SD card and accessed that way on any computer or when the Pi is booted and running
#dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
Reboot to apply the change:
pi@raspberrypi:~ $ sudo reboot
Before thinking about Minecraft lets check we are receiving serial.
Check you've got serial installed:
sudo apt-get install python-serial
Verify it all works by using screen
Install it first if you dont have it; its handy!
sudo apt-get install screen
then listen on the /dev/ttyS0 serial port at 9600 baudrate that your HAT communicates with.
screen /dev/ttyS0 9600
Power your other RF-Craft HAT in EXT mode and set a NODE value of 1 using the 1234 switch (next to the analoginput block on the board), and you should receive the message 1,1 which means NODEID=1,Button Pressed
TIP To set a node ID of 1 Just set the node switch 1 to ON which is 1 in binary or for a node ID of 3 set the node switch 1 and 2 to ON, 3 in binary.
Now try HelloSerial.py on your Pi with python HelloSerial.py