VRAM -> VRAM DMA
Posted: Tue Aug 19, 2008 8:43 pm
Hello I have 2 questions:
1- Do somebody know what happen when you launch a vram to vram dma transfert immediately (well actually some cycle after) after another one?
I know the dma adresse registers act as counter during dma transfert so logically trouble must/can occur...
However I simulated parallax using dma and my display is not corrupted, a good surprise but I would like to be sure.
2- Is dma speed dependant of the VCE pixel clock? If I tweak $400 bit 0 and 1 VCE reg during vblank (and restore is befor the vsync end in order to not destroying my display) to switch from 5 to 7 or 10Mhz did my dma'll be quicker?
1- Do somebody know what happen when you launch a vram to vram dma transfert immediately (well actually some cycle after) after another one?
I know the dma adresse registers act as counter during dma transfert so logically trouble must/can occur...
However I simulated parallax using dma and my display is not corrupted, a good surprise but I would like to be sure.
2- Is dma speed dependant of the VCE pixel clock? If I tweak $400 bit 0 and 1 VCE reg during vblank (and restore is befor the vsync end in order to not destroying my display) to switch from 5 to 7 or 10Mhz did my dma'll be quicker?