I'm using an external power source to power an MBED module. I have the UART transfer and receive ports connected to a MAX232 level switcher in order to make the signals compatible with RS232. From there the wires go to an RJ-45 connector, which goes to a DB9 connector that is connected to a USB-DB9 converter. This is connected to the laptop.

With this setup, I should be able to program the CPU to write text which will appear in a terminal program like HyperTerminal in Windows? I've tried several things, but haven't been able to get any input in HyperTerminal. I can get it to work if I use a USB connection though.

I've already checked that everything is powered and grounded. I've also checked the connections. What can I do next to figure this out?

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    \$\begingroup\$ possible duplicate of Using a laptop to communicate with an MBED module \$\endgroup\$ – Leon Heller Feb 22 '11 at 11:59
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    \$\begingroup\$ are you selecting the correct speed for your serial, and the correct port(hyperterm settings)? What is the code you are using on the mbed(similar to what i posted)? have you tried just the serial port and not a usb to serial converter? I would also suggest trying what Joby Taffey has suggested as well. \$\endgroup\$ – jsolarski Feb 22 '11 at 12:25
  • \$\begingroup\$ I think this question has enough of a different question posed that people searching from google may come to this question when they would have never found the other, from that perspective it should remain open. \$\endgroup\$ – Kellenjb Feb 23 '11 at 1:16

I'd advise that you check your serial link. Disconnect the serial cable from the mbed and short the TX and RX lines. If it's working, you'll see your data echoing back as you type it from the PC.

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  • \$\begingroup\$ Yes, there was something wrong there. \$\endgroup\$ – 200ok404notfound Feb 23 '11 at 5:45

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