Hi
I am trying to build a simple comm spy cable / circuit which will enable me to monitor comm between DCE and DTE.
Now I have built one and it works absolutely ok between 2 PCs but when I want to use it to monitor communication between an embedded device and another embedded device it just shows me garbage/ diff data then expected when I put my serial sniffers probe on the Tx pin of the device. In theory I think it should work if I take Tx from the embedded device and gives it to the Rx of the PC port with Gnd attached. but It gives me the bad characters which is not the actual data I want to see.
what should I do here,, do I need to build some special cable or circuit for this..
specs of Embedded Device A:
basically it is a custom built device built for updating EEPROMS/ Flahes of other embedded devices we have.it is a FTDI 2232C based device takes instructions from pc / host software via USB and then uses 74125 Tri state buffer in between and finally sends out the data thru converted serial .Now I dont know why 125 is used here as I dont think(based on my limited knowledge, correct me if I am wrong) there is a need, all the conversion has already been done by 2232C FTDI I think.
specs of embedded device B:
It can be any device which needs to be programmed ,
Now what should I do to sniff the serial comm b/w both of the devices.
please help
thanks
I am trying to build a simple comm spy cable / circuit which will enable me to monitor comm between DCE and DTE.
Now I have built one and it works absolutely ok between 2 PCs but when I want to use it to monitor communication between an embedded device and another embedded device it just shows me garbage/ diff data then expected when I put my serial sniffers probe on the Tx pin of the device. In theory I think it should work if I take Tx from the embedded device and gives it to the Rx of the PC port with Gnd attached. but It gives me the bad characters which is not the actual data I want to see.
what should I do here,, do I need to build some special cable or circuit for this..
specs of Embedded Device A:
basically it is a custom built device built for updating EEPROMS/ Flahes of other embedded devices we have.it is a FTDI 2232C based device takes instructions from pc / host software via USB and then uses 74125 Tri state buffer in between and finally sends out the data thru converted serial .Now I dont know why 125 is used here as I dont think(based on my limited knowledge, correct me if I am wrong) there is a need, all the conversion has already been done by 2232C FTDI I think.
specs of embedded device B:
It can be any device which needs to be programmed ,
Now what should I do to sniff the serial comm b/w both of the devices.
please help
thanks