tlk1211 for RGMII

Hi Diego:

In DDR mode the device can not directly convert RGMII into an Ethernet serial output.  The RGMII parallel bus is typically un-encoded and thus needs to be encoded using 8b/10b coding before transmission, but this encoder isn’t implemented in the TLK device.  So, the RGMII bus (or GMII bus for SDR mode) would need to be encoded outside the TLK prior to being serialized.

Regarding to EVM User’s Guide for TLK1211 you can refer to the document of TLK1221 that is very similar to TLK1211 (just without JTAG/MODESEL).

lit/ug/sllu100/sllu100.pdf

Regards!

Hello Luis,

thanks for your answer,

in the application I am thinking on this will not be an issue, because I will not use it as a serial Gigabit Ethernet, so in the other board I will connect to a deserializer and to other MAC, and I will not use the serial side as a Gigabit Ethenet:

MAC ---(RGMII parallel)--> TLK1211----(serial)----> TLK1211 ---(RGMII parallel)--> MAC.

....................board 1...................-------backplane-----------...............board 2.........................

the problem that I have now is that when I make hyperlynx simulation between the Mac and the TLK1211 it is fine but when I simulate from TLK1211 to the MAC it is not ok, there is anything wrong with the IBIS model of the TLK1211?

Regards

Diego

Hi Diego:

This model is designed as an aid for customers of Texas Instruments. 

TI and its licensors and suppliers make no warranties, either expressed or implied, with respect to this model, including the warranties of merchantability or fitness for a particular purpose. The model is provided solely on an "as is" basis. The entire risk as to its quality and performance is with the customer.

What kind of issues do you have in your simulation?

Regards!

Luis Omar Morán 

hello Luis,

1.- I attached a file with the simulation, but according the MAC, the rise and fall time has to be max. 750 pseconds 

blue line- TLK1211

pink line- other serializer  with good levels.

2.- if we serialize RGMII data NOT coded 8b/10b through the TLK1211 the TLK1211 receiver could be able to recover the CLK from serial link?

Regards

Diego

Hi Diego:

1. Could you try with IBIS file of TLK1221 only to double check if the IBIS model of TLK1211 doesn´t have any issue.

2. There are a couple potential issues with that. One is that, clock recovery may be difficult. The 8b/10b coding scheme ensures that you have enough transition density for a clock recovery circuit to function properly. Another issue is with determining the parallel bit boundaries (which bit is the first, second, etc.). The receiver usually does this by detecting the comma code (0011111) which occurs in certain reserved codes in the 8b10b code set. If the receiver does not see this pattern, it will be unable to synchronize to the data pattern. 

Regards!

Luis Omar Morán Serna

TI - HSI