Problem with conection RJ45 and LPC1768

09 Jul 2012

Hi, good afternoon:

i have the lpc1768, and i make a bridge with the router 2wire 2701HG-T and PC, but my conection broke, i try many conections ( http://mbed.org/cookbook/Ethernet-RJ45 ), i have the sniffer program but my conection broke, i conect a switch 3com officeconnect dual speed 16 ports to a router 2wire, and the conection is between the switch and pc, but the conection broke again, i read that the lpc1768 it`s possible to configurate in mode AUTO MIDX, how to make it? a example code? or the combination of the tx+ with rx+ (pin 3) and tx- with rx- (pin 6)is correct?, please help me, the pins are killing me .

thanks!!!

09 Jul 2012

which RJ-45 are you using? the pin outs are different for just about every model. and don't forget to connect the ground an 3.3V line.

09 Jul 2012

/media/uploads/bodoke1969/img-20120708-wa000.jpg i use the two rj45 (568a and 568b) and the conection still brokes, i join the cable tx+ tx- and rx+ rx- with other out cable and i conect the cable in the lpc1768, and the conection broke again, i dont use the 3.3V line because i join the cable to lpc1768. can you help me? /media/uploads/bodoke1969/img00128-20120708-1950.jpg /media/uploads/bodoke1969/img00129-20120708-1952.jpg /media/uploads/bodoke1969/img-20120708-wa001.jpg

09 Jul 2012

i cant see the pictures above, can you fix it?

09 Jul 2012

not sure it its going to work with a cable directly to the mbed pins. Normally the RJ-45 interface provides magnetics and some other connections. if you look at a sample diagram of a RJ45 jack with magnetics, you will see a lot more than a direct connection between t+, t-, r+, and r-

I could be wrong though.

09 Jul 2012

theres a port there that describes how to connect bare wires to the mbed pins. might work if the condition is right (short cables, no poe, etc)

09 Jul 2012

I uploaded again the images, hope you can see it now, but i also have to tell you that this conection, was used and work fine, but now i dont know what to do :(

09 Jul 2012

if you have it working before and now its not working, something might have happened. You did read the warning on using direct connection right without all the protections RJ45 magnetics provide.

Not sure how are you going to fix if you killed the ethernet phy somehow (its another chip in the mbed)

09 Jul 2012

I make test in the mbed and work fine the conections of ethernet, i see that problem is to configurate the lpc1768 in mode AUTO MDIX or other solution. :)

12 Jul 2012

Why does the photo appear to show three cables interconnected?

Which cables are they?

17 Jul 2019

Can anybody show how to connect to the Internet using RJ45 and LPC1768. I found https://os.mbed.com/cookbook/Ethernet-RJ45 and https://os.mbed.com/handbook/Ethernet-Interface but they don't show anything related to hardware