Setting DBUS_WB_TYPE = "B3_READ_BURSTING" causes lockup

Open jefferybond opened this issue 3 years ago • 1 comments

If I set the DBUS_WB_TYPE parameter to "B3_READ_BURSTING", then the CPU locks up when attempting the first data access.

It seems that the dbwm_we_o output gets asserted, and a valid address is presented on dwbm_adr_o, but the dwbm_stb_o / dwbm_cyc_o outputs remain low, and no bus access happens. CPU locks up from this point on.

Setting DBUS_WB_TYPE="CLASSIC" allows it to work again. Also, setting IBUS_WB_TYPE="B3_READ_BURSTING" causes no issue - only seems to affect the data bus.

Apr 11 '22 10:04 jefferybond

Hi @jefferybond, I usually run mor1kx with mode B3_REGISTERED_FEEDBACK for both ibus and dbus. Sorry I haven't tried B3_READ_BURSTING so it's very likely there could be issues here. Would you be able to do further investigation to figure out what is the issue with B3_READ_BURSTING?

Apr 11 '22 20:04 stffrdhrn