ngpc: core hangs up when starting a cartridge

jotego / jtcores

FPGA cores compatible with multiple arcade game machines and KiCAD schematics of arcade games. Working on MiSTer FPGA/Analogue Pocket

https://patreon.com/jotego

GNU General Public License v3.0

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Closed jotego closed 3 months ago

jotego commented 3 months ago

The ngpc starts correctly in color mode and the set up menu works, but when a cartridge is inserted the core hangs up.

Reproduce the problem with: sim.sh -cart cartgame.ngc -inputs pulse.in -video 700. It will get stuck at frame 659:

frame_00659

The CPU stays in a loop leaving it briefly only for blanking interrupts.

$4e01 is a RAM0 address. The interrupt service increments this position:

jotego commented 3 months ago

The palette mux was registered and the extra clock cycle was altering the data going into the CPU. Fixed in 305a9b7c