01-12-2018 05:03 AM
Hi, i'm working on GTX and i'm new to this, i read the example design doc PG182 and simulated the gtx wizard of the example,and they are doing loop back. but gtwiz_userdata_rx_out[31:0] didn't match gtwiz_userdata_tx_in[31:0] , please someone worked on it help me. i have not used any encoding and i have not used system IBERT core also,
i'm sending 32bit parallel data and i need the serial data at 10.3125 Gbps, and my reference clock is 64MHz( 150/250 MHz is also good for my project)
HERE is the example stimulation:
01-12-2018 06:18 AM - edited 01-12-2018 06:18 AM
The transceiver serializes the bit stream in TX and deserializes it in the RX. The alignment at the bit-level will most likely not match and thus encoding and some kind of synchronization character is required such that the transceiver can bit and byte align the received datastream into something meaningful.
If you do not have this functionality in the transceiver, it must be implemented outside.
01-12-2018 08:34 AM
In addition to the bit alignment problem you might run into a problem with the DC balance if you are not using an encoding scheme. If you are just sending raw data over the link the number of 1's and 0's won't be balanced which will cause a charge to develop on the ac coupling caps which will lead to data errors. You would probably save yourself some time if you convert to a protocol. At 10G you would need to use 64B/66B encoding.
01-12-2018 10:00 AM