08-18-2016 01:53 AM
I am trying to transmit mass data from a VC707 board to another VC707 board via GTX at 10 Gbits/sec.
To do so, first, I worked with a single VC707 board.
I connected the differential RX ports of GTX on SMA connectors to the differential TX ports of GTX on SMA connectors.
Using a single Transceiver IP for both transmit and receive, I observed data transfer at 10Gbits/sec without any error.
Then I started to use both of the VC707 boards.
I cross connected the RX ports of the boards to TX ports of the boards.
At 6.25 Gbits/sec, while sending comma characters only I observe erroneous bytes at receive sides of both boards.
However at 4 Gbits/sec, while sending comma characters only I do not observe any erroneous bytes at receive sides of both boards.
In the figures below you can find the received signal patterns measured differentially from RX ports of GTX
I am using 40cm RF cables of which phase latency are almost same.
The grounds of the boards are not necessarily matched since the signals are AC coupled.
Should I change any parameters while tranmitting from one board to the other?
08-18-2016 03:04 AM
Are you using any specific protocol for these tests or is this a custom protocol.
Can you try using the 10G Ethernet subystem to test your 10Gbs data rates.
08-18-2016 03:05 AM
Can you share .xci file to know the details about your IP customization?
08-18-2016 04:15 AM
first of all, the problem I mentioned is not related with the protocol since the receiver does not take the comma bytes correctly.
I mean there is problem even if the transmitter sends only comma bytes not data bytes.
I do not use specific protocol. Instead I use simple protocol which is verified when I use single VC707 board for data transmission.
The verified simple protocol is like this.
state 0: send 4 bytes of comma, make read enable of data fifo 1, state<=state+1.
state 1: send 4 bytes of comma, make read enable of data fifo 0, state<=state+1.
state 2: send 4 bytes of comma, if valid data from fifo buffer 512 bit data from fifo to be send and go to state 3.
if not valid go to state 0.
state 3-17: send 4 bytes of data, state<=state+1
state 18: send 4 bytes of data, state<=0
I am also attaching the .xci file.
08-26-2016 10:40 AM
09-01-2016 02:01 AM
Actually, I was using LPM-Auto Mode for RX Equalization.
I tried to use DFE-Auto Mode for RX Equalization which increased the amount of erroneous comma values received.
Eventhough I still receive receive erroneous comma values in LPM-Auto Mode, LPM-Auto Mode is more successfull.