Character Conversion DMA issues on SA1

[blackmagemathie]

upon upload/conversion using CCDMA (type 1 (BW-RAM to I-RAM), 2bpp mode, VRAM horizontal character size set to 2^0), graphics are garbled and/or duplicated (see forum thread for more details).

• in-game hooks, savestates, etc. were all disabled during testing
• issue occurs on more than one flashcart/console
• issue occurs with more than one CCDMA system
• randomised writes/reads test suggests issue occurs during actual Character Conversion (or when setting it up), and Bitmap Access Area is not responsible
• further tests suggest issue may be buffer-related

[mrehkopf]

Thanks for the greatly detailed report on the forum and test ROMs. Hope to be able to look into it soon :)