[Libre-soc-dev] daily kan-ban update 03jul2022

[Cesar Strauss]

Em 04/07/2022 19:02, Cesar Strauss escreveu:
> Em 03/07/2022 15:49, Tobias Platen via Libre-soc-dev escreveu:
>> orangecrab WERROR: Failed to find a route for arc 2 of net 
>> ddrphy_ddr3_0__a__o_fclk.
> 
> Maybe some attribute is missing, on the ls2 clock generator, or the
> PLL. I'll compare with LiteX / LiteDRAM, and see if I can spot the
> difference.
> 

The LiteX target file for the OrangeCrab has an "ECLKBRIDGECS":

https://github.com/litex-hub/litex-boards/blob/32f507cc08aa4b969d952143f9fc4fdf82228951/litex_boards/targets/gsd_orangecrab.py#L109

The LiteX target file for the Versa doesn't have it.

Neither does our ecp5_crg.py, on ls2 (for any target).

 From the "ECP5 and ECP5-5G High-Speed I/O Interface" manual:

"Edge Clocks (ECLK) are high-speed, low-skew I/O dedicated clocks. They
are arranged in groups of two per I/O bank on the left and right sides
of the device. Each of these Edge Clocks can be used to implement a
high-speed interface. There is an Edge Clock Bridge (ECLKBRIDGECS) that
allows you to build large interfaces by bridging the Edge Clocks from
one bank to the other on the same side or from one side to the other side."

I guess the Versa has all DDR3 pins on just one bank, while the
OrangeCrab has them on different banks, thus needing an ECLKBRIDGECS.

Cesar