Changes

Jump to: navigation, search

ASIC

1 byte added, 7 July
/* Known flaws */
*PPI emulation is not correct as the original 8255 does not need validation. On ASIC emulation, this validation is needed so some programs written for "old CPCs" will not be able to get keyboard state.
*Z80 IM2 mode is bugged. In this mode, the Z80 I register gives the high word byte for vector table. ASIC gives the low word byte from IVR and the devices that generate interrupt (raster and DMAs channels). ASIC may generate a bad values value and make the raster interrupt routine is called instead of DMA0 routine if the Z80 is running particular portions of memory. See [[Plus Vectored Interrupt Bug]] for more details.
*There is a conflict between programmable interrupts and some CRTC settings (line screen split). That will cause the RAM refresh to stop and the memory content will be quickly corrupted causing machine crash.
8,338
edits