[lowrisc-dev] Problem compiling bare metal examples

Alexis Ramos Amo aramosam at nebrija.es
Thu Mar 3 12:28:15 GMT 2016

Thank you both for your answer,

I've uploaded the log to dropbox

The modification I've made is integrating chip_top.sv (and all its hierarchy) inside the IP wrapper, alongside with the other verilogs. Of course I've declared I/O of chip_top into the IP wrapper and I've connected the clock given by the IP as output, to the chip_top clk

If I run report_property [get_cells ram_reg_1] {LOC} I get "No cells matched 'ram_reg_1'  . In the RTL module I see the same components as the default lowRISC configuration.

I'm going to try with don't touch constraints but any other ideas are welcome 
Best regards

Alexis Ramos Amo 

-----Mensaje original-----
De: Wei Song [mailto:ws327 at cam.ac.uk] 
Enviado el: jueves, 03 de marzo de 2016 12:29
Para: Stefan Wallentowitz; Alexis Ramos Amo; lowrisc-dev at lists.lowrisc.org
Asunto: Re: [lowrisc-dev] Problem compiling bare metal examples

Hello Alexis and Stefan,

Strangely I cannot see the log attached but according to Stefan's confirmation, the problem indeed is related to the boot ram.
So the lowRISC SoC boots from an on-FPGA block-RAM named "ram" in chip_top.sv.
Search for comment "the inferred BRAM".
The script bmm_gen.py is trying to automatically identify this block-ram then the compiled hello executable can be loaded into it.

For your modification to the lowRISC SoC, have you changed anything related to this "ram", or is there any change to the chip-level interconnect that makes Vivado to optimize the ram away?

Best regards,

On 03/03/16 10:59, Stefan Wallentowitz wrote:
> Hash: SHA1
> On 03.03.2016 11:53, Alexis Ramos Amo wrote:
>> Hello Stefan, thank you for your answer.
>> Here is the log.
>> Best, Alexis
> Hi Alexis,
> from the log I can confirm it did not find the RAMs:
> WARNING: [Vivado 12-180] No cells matched 'ram_reg_*'.
> Maybe Wei has a good idea about this issue, otherwise I hope I can 
> find some time later today to have a look at my project logs to 
> compare them.
> Best,
> Stefan
> Version: GnuPG v2
> iEYEARECAAYFAlbYGR8ACgkQuMYtsrn2U9wk3ACcDkIj67jzJUaQ6/NdyWE1webf
> YEwAn3oUTYowOh/hfXWdHGzxxZ3aArhn
> =p+vO

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