MiSTer FPGA Forum

Finally got it. No VIC IRQ occurs and it is in fact not necessary for PAL/NTSC detection: When the VIC is asked to signal e.g. rasterline 311, it sets $D019 indicating the rasterline 'irq' to have occured as soon as the line is processed by the VIC. This happens even in case VIC IRQ signalling is switched off. So my misunderstanding was thinking th...

Thank you for your answer. Yes, CLI is done right before the jmp($a000) to basic, but as I tried to explain, this is too late because the flag has already been read out at this point and used within the reset routine before. Furthermore, VICII would not signal the IRQ even in case the CLI would have occured earlier because having the VIC signal an ...

Hello, maybe this is a bit off topic for MiSTer, but maybe some experts on the C64 FPGA implementation may help me by finding an answer which is/was also of interest by the FPGA implementation of the great C64 core. I am currently working on an implementation of the C64 using the neo6502 hardware and I noticed that on RESET, the C64 the Kernal rout...