Microcode ROM from generic version doesn't synthesize in Vivado 2021.1

[willisblackburn]

I tried to use the generic core within Vivado 2021.1. The error I'm getting is:

[Synth 8-273] error in $readmem data: non-binary digit to $readmemb ["microcode.v":12]

I tried a lot of different things. Vivado doesn't want to open a file with an extension called "hex," so I tried "mem" and "rom," thinking that maybe the extension influences how Vivado parses the file. I tried removing all the comments. I'm not sure what the issue is; the file looks okay to me.

[Arlet]

Maybe it has trouble with the underscores ?

[willisblackburn]

I’ll try that. It would be disappointing, as the file is nicely formatted and the underscores shouldn’t cause any parsing problems.

[m1geo]

Working fine with no file contents modifications in Vivado 2024.1. Did have to rename microcode.hex to microcode.mem to get the tool to recognise it as a memory file.

[m1geo]

Scrap my previous comment, it would simulate OK but when I come to synthesise it, it failed:

Turned out to be caused by Vivado needing a space between the "@" and the hex offset as detailed at the end of this forum post: https://adaptivesupport.amd.com/s/question/0D52E00006hpi7iSAA/readmemb-problem-synth-8273?language=en_US

Removing the space between the "@" and the hex address fixed the error, but then the parser silently failed, the CPU had no microcode, and the synthesis optimised it away. I had to massage the microcode into inline Verilog, as so:

Finally got it working, synthesised and running at 100 MHz on a Xilinx 7A35T!!