We are looking for some help testing the hardware stream UART implementation for OMAP L138 . To test the implementation, I use minicom to emulate the other end of a serial link, and I'm looking for some idea of how to set it up.
I have a simple application that sends messages via UART from OMAP to minicom. This works as expected if both OMAP and minicom are configured to NOT use hardware flow control. When I turn on hardware flow control, I don’t see the output on the minicomputer.
Here is a list of the steps that I followed:
- Configured minicomputer for hardware flow control (Ctl AO to open the minicom serial port setup menu, and F to enable hardware flow control).
- Using
stty I include a call to rts / cts stty -F /dev/ttyS1 crtscts . Using the command stty -F /dev/ttyS1 -a , I can confirm that crtscts is enabled.
The two above changes ensure that hardware flow control is enabled in the terminal program and in the UART driver. UART on OMAP is also configured to use hardware flow control.
However, the changes to the minicom listed above seem insufficient for the flow control to work properly. After starting the application, the RTS signal (send request) from OMAP goes low, indicating to minicom that it wants to send data. If configured correctly, minicom should output the OMAP CTS signal (clear for sending) and start receiving data until it reaches the specified threshold for the receive buffer. This is not happening. CTS entry into OMAP is always high. Just for the bumps, I tried to reduce RTS to CTS on OMAP and voila, the expected messages do appear on minicom! Here's an image showing how both are connected.
From what I tried, it seems that I missed something, because I tuned it with a minicar. Any suggestions appreciated.
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