Using Xbee with FTDI cable


I am using XB24-AWI-001 module.
I am facing unique behavior with these modules when using them with FTDI cable.

I have TTL-232R-3V3 FTDI cable. When I use this with X-CTU and communicate with the module over AT / API mode I get the correct response consistently.

Same setup I am using with ubuntu & fedora host machines.
Both of them claim to have a FTDI driver.

I use terminal utility called minicom to communicate with the modules.
With minicom I was able to communicate over AT commands. I can see the response on the scope and I do receive the correct data.

:frowning: I cannot use API mode with minicom. Cannot write ascii API frame directly.

So now I have written some code snippets to send AT commands to the module and read its response. Similarly I have assembled API command frames (like reading DL of the module) .

When I execute the code, I can see the AT commands sent on TX line AT commands response on RX line, API frame packet on TX and correct API frame packet response on RX on by scope.

As soon as I connect back the RX line (on which I am receiving the API response) back to FTDI cable. I dont get any response. For AT commands request/response I can see the waveforms on the scope and able to read it from my code as well. Only with API packet response as soon as I connect back to FTDI the response vanishes (Cannot see on scope , stays pulled high … also read() returns -1)

Any idea why this happens only in API mode ??
Any pointers on how to debug this issue ??