Trenz Electronic GmbH Support Forum

Trenz Electronic Products => Trenz Electronic FPGA Modules => Topic started by: WallyG on July 19, 2017, 12:33:40 PM

Title: turn on MGT reference clock to TE0741
Post by: WallyG on July 19, 2017, 12:33:40 PM
Hi

According to the TE0741 Wiki table 7 here ( https://wiki.trenz-electronic.de/display/PD/TE0741+TRM#TE0741TRM-Clocking ), the TE0741 FPGA gets 3 clocks from a Si5338 clock generator:

2 x 125 MHz MGT reference clocks + 1 x 100 MHz clock.

From my measurements, 125MHz CLK2 to FPGA bank 115 is Off.

How do I turn it On?

(The second 125MHz clock to bank 116, and the 100MHz are o.k. (on))

thanks for any help
Title: Re: turn on MGT reference clock to TE0741
Post by: JH on July 20, 2017, 08:31:35 AM
Hi,

at the moment we have no example design online for TE0741, which configure the SI5338.
Here the main steps:

We have a example for TE0841 online, you can check code there:

br
John
Title: Re: turn on MGT reference clock to TE0741
Post by: WallyG on July 20, 2017, 09:46:28 AM
Thank you for helpful feedback John

Two things occur :

1. Does that mean the Trenz Wiki Table 7 and Fig 3 are indeed wrong and "MGT CLK2" is not working ? ( https://wiki.trenz-electronic.de/display/PD/TE0741+TRM#TE0741TRM-Clocking ),

2. I get the general idea of reprogramming the SI5335 thru' I2C.
I'm puzzling over how to use the FPGA to do the re-programming however.
On the TE0741 the SI5335 itself supplies the 100MHz FPGA system clock.
Does this create a "catch22" ? (= When the FPGA resets the SI5335 during reconfiguration, the system clock to the FPGA will disappear, and further I2C commands won't be sent...)

thanks for any assistance

Title: Re: turn on MGT reference clock to TE0741
Post by: JH on July 20, 2017, 10:05:29 AM
Hi,
1:
this is disabled by default firmware. Can be enabled over I2C.
2: Use Startup Primitive for MCS CLK, with this you can get access to appr. 65MHz configuration clk.
IP for 7 Series is included in:
https://shop.trenz-electronic.de/en/Download/?path=Trenz_Electronic/TE0714/Reference_Design/2016.2/vio_led
--> led_vio\ip_lib\PRIM_STARTUP
br
John