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planetarian / spindash-fpga

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Issues on GW5A but not GW2AR #1

Open planetarian opened 2 months ago

planetarian commented 2 months ago

If the if (rst) checks are kept in code at the following locations: https://github.com/planetarian/jt12/blob/7255be596de03fd7c9daaa438fb9d12a97c09bd8/hdl/jt12_mmr.v#L211 https://github.com/planetarian/jt12/blob/7255be596de03fd7c9daaa438fb9d12a97c09bd8/hdl/jt12_reg_ch.v#L105

..then the RST signal appears to be permanently held low, regardless of input.

In the case of jt12_reg_ch.v, i discovered that if I remove enough of the assignments within the else begin block, RST works. Particularly, if I remove enough of the assignments such that there are no more than four bits being assigned in total, RST works. e.g. reg_rl and reg_ams can both be assigned, but if reg_pms is assigned, the others must be removed.

Gowin FPGA Designer produces no warnings or errors which appear to be related to the issue.

planetarian commented 2 months ago

Issue seems to be more broad than just this. On the GW2AR/Tang Nano 20K, everything runs flawlessly. The GW5A/Tang Primer 25K, however, exhibits all kinds of weirdness.