disappearing top module "constant output" signals
https://ftp.libre-soc.org/disappearing_sdram_dm.tgz
jean-paul: litex initialises sdram_dm to zero however this is a placeholder for later being resolved by the litex team whilst we work out the iopads.
unfortunately somehow in between ls180.il and ls180.vst the sdram_dm signals "disappear" from the port list. it could be an overzealous yosys, it could be alliance, i don't know which.
Edited by Luke Leighton