Yeah, I don’t have bus arbitration yet but I have /DTACK and a couple other signals. The ‘320 and ‘120 are both capable of bus mastering under my vme.cpp. A card can assert a signal line which gets distributed to all attached cards on the backplane as a callback for them to override (or ignore if they don’t care).

The way I have it set up is using install_device to insert handlers into the VME A24 address space, then having a memory handler on each card to perform read/write operations to A24 when they call out to VME. I don’t have all the signal logic going yet for that but it works well enough to let 120bug interact with the 320 via its standard monitor commands and for the 120 to detect the 050 during boot. Being able to overlay memory regions and handlers is very helpful.

The 120 does fail its self test and I’m not sure why, it seems to be something with the 68000 core I haven’t worked out. I added a two-byte ROM hack to the driver to get it to pass where it locks up so I can at least get to a console.

Last edited by Luigi30; 12/25/21 06:28 PM.