I would like to connect to a serial Console server to the beagelboard X15 serial debug port, can’t use a Prolific or FTDI protocol converter. This a true serial console server. Using a cut serial female cable - DB9 female end connects to the console server. The other end connects to the X15. DB9 Pin 3 connects to pin 4 on the x15, DB9 Pin 2 connects to pin 5 on the x15. The Rx from the console server goes to the TX of the X15, The Tx from the console server goes to the Rx on the X15. It responds just fine and typing is reflected real time. The key strokes show up scrambled. The serial settings are set to on the console server and the X15 and Linux ( stty and agetty ) 115200, 8, N, 1 ,No hardware or software flow control is used. I have an XM that works just fine and have mimicked the three wires that are used on the XM native serial RS232 port. When I run stty I can set the baud rate, But I believe it is false indicator. When I run set serial I get a completely different answer
setserial /dev/ttyS2 baud_base 115200, this comes back just fine, but if I check again
Output of stty:
stty -aF /dev/ttyS2 speed 115200 baud; rows 24; columns 80; line = 0;
I believe my issue is here. I need to get setserial to coincide with stty and agetty and lower the baud rate so that I can connect it directly to the tty server.
Hi Robert,
Yes the ground wire is connected. I did not mention it in my post earlier I apologize. from the X15 the ground lead header pin #1 connects to pin5 on the DB9. Which also the ground pin on the console server. I did not make any voltage adjustments at all. I thought since I am bypassing the TTL protocol converter it would be safe to treat the signal from the header as traditional DB9 RS232. I am providing a more longer winded description of diagnostics and results
I would like to connect to a serial Console server to the beagelboard X15 serial debug port, can’t use a Prolific or FTDI protocol converter. This a true serial console server. Using a cut serial female cable - DB9 female end connects to the console server. The other end connects to the X15. DB9 Pin 3 connects to pin 4 on the x15, DB9 Pin 2 connects to pin 5 on the x15. The Rx from the console server goes to the TX of the X15, The Tx from the console server goes to the Rx on the X15. It responds just fine and typing is reflected real time. The key strokes show up scrambled. The serial settings are set to on the console server and the X15 and Linux ( stty and agetty ) 115200, 8, N, 1 ,No hardware or software flow control is used. I have an XM that works just fine and have mimicked the three wires that are used on the XM native serial RS232 port. When I run stty I can set the baud rate, But I believe it is false indicator. When I run set serial I get a completely different answer
setserial /dev/ttyS2 baud_base 115200, this comes back just fine, but if I check again
Output of stty:
stty -aF /dev/ttyS2 speed 115200 baud; rows 24; columns 80; line = 0;
I believe my issue is here. I need to get setserial to coincide with stty and agetty and lower the baud rate so that I can connect it directly to the tty server.
Just rereading your response how do I apply the 3.3 volts? I would expect the connecting devices to supply the voltage they need and to be generic. Because no one can predict what the connecting devices are going to be. RS232 is subch an established technology. I have never had to worry about voltage in theses types of cases. But going along with what you are presenting according to the drawing there is 3.3v on the RX line. Where can I get the 3.3 on the beagle board X15 so I can apply it to the RX line via a 10k resistor, its numbered as R236. I would expect that voltage to be their already.
Thanks
For your help and just keep in mind I am interfacing with a device that is RS232
Just wanted update my own post I was able to figure out the issue was with the RS232 ttl protocol converter. It turns out I just needed to up the voltage to 4.17v. As soon as I did that the text characters sent and received came in crystal clear. Even though the board is rated for 3.3 to 5.0v and the BB X15 should see 3.3 upping the voltage just a wee bit did the trick.