Robert M
Hello all,
I've been compiling and testing various RoboticsCape example codes on the BBBlue. The distribution I currently have installed is the latest IoT image: bone-debian-9.2-iot-armhf-2017-10-10-4gb.
I have tested rc_uart_loopback on UART0, UART1, UART2, and UART5. Following the instructions in the example code, I shorted the TX and RX pins together on a breadboard and ran the program for each UART. The other three worked normally, however UART0 has been giving me problems.
On testing UART0, one of four outcomes may be encountered:
- UART0 fails to initialize:
debian@beaglebone:~/bin/RoboticsCapeInstaller/Robotics_Cape_Installer/examples/rc_uart_loopback$ sudo ./rc_uart_loopback 0
testing UART bus 0
cannot set uart0 attributes
Failed to rc_uart_init0
Exiting Cleanly
- UART0 times out:
debian@beaglebone:~/bin/RoboticsCapeInstaller/Robotics_Cape_Installer/examples/rc_uart_loopback$ sudo ./rc_uart_loopback 0
testing UART bus 0
Sending 11 bytes: Hello World
timeout reached, 0 bytes read
Exiting Cleanly - UART0 reads back various amounts of whitespace:
debian@beaglebone:~/bin/RoboticsCapeInstaller/Robotics_Cape_Installer/examples/rc_uart_loopback$ sudo ./rc_uart_loopback 0
testing UART bus 0
Sending 11 bytes: Hello World
Received 11 bytes:
Exiting Cleanly - UART0 works properly (occasionally):
debian@beaglebone:~/bin/RoboticsCapeInstaller/Robotics_Cape_Installer/examples/rc_uart_loopback$ sudo ./rc_uart_loopback 0
testing UART bus 0
Sending 11 bytes: Hello World
Received 11 bytes: Hello World
Exiting Cleanly
The source code implies that UART0 is on a debug header. Could it be periodically in use by something in the background? Where can I find more information about the "debug header?"
*******************************************************************************
* rc_uart_loopback.c
*
* This is a test to check read and write operation of UART buses.
* For this example to work, connect the RX and TX wires of one of the included
* 4-pin JST-SH pigtails and plug into the UART1 or UART5 headers. You may also
* elect to test UART0 on the debug header or UART2 on the GPS header.
* The test strings this programs transmits will then loopback to the RX channel.
*******************************************************************************/