66470 video and system controller 19901219/wjvg 1fffe0 csr = control and status register w ........ 00...... DM = slow timing speed, normal dram mode w ........ 01...... DM = fast timing speed, page dram mode w ........ 10...... DM = fast timing speed, nibble dram mode w ........ 11...... DM = slow timing speed, dual-port vram mode w ........ ..1..... TD = 256/64 k dram's w ........ ...1.... CG = enable character generator w ........ ....1... DD = rom data acknowledge delay w ........ .....1.. ED = early dtack w ........ ......0. not used w ........ .......1 BE = enable bus error (watchdog timer) r ........ 1....... DA = vertical display active r ........ .1...... FG = set during frame grabbing (if fg in dcr set) r ........ ..xxx... not used r ........ .....1.. IT2 = intn active r ........ ......1. IT1 = pixac free and intn active r ........ .......1 BE = bus error generated by watchdog timer 1fffe2 dcr = display command register w 1....... ........ DE = enable display w .00..... ........ CF = 20 MHz (or 19.6608 MHz) w .01..... ........ CF = 24 MHz w .10..... ........ CF = 28.5 MHz w .11..... ........ CF = 30 MHz w ...1.... ........ FD = 60/50 Hz frame duration w ....00.. ........ SM/SS = non-interlaced scan mode w ....01.. ........ SM/SS = double frequency scan mode w ....10.. ........ SM/SS = interlaced scan mode w ....11.. ........ SM/SS = interlaced field repeat scan mode w ......1. ........ LS = full screen/border w .......1 ........ CM = logical/physical screen w ........ 1....... FG = 4/8 bits per pixel w ........ .1...... DF = enable frame grabbing w ........ ..00.... IC/DC = ICA and DCA inactive w ........ ..01.... IC/DC = ICA active, reduced DCA mode (DCA sz=16 byts) w ........ ..10.... IC/DC = ICA active, DCA inactive w ........ ..11.... IC/DC = ICA active, DCA active (DCA size=64 bytes) w ........ ....aaaa VSR:H = video start address (MSB's) 1fffe4 vsr = video start register w aaaaaaaa aaaaaaaa VSR:L = video start address (LSB's) 1fffe6 bcr = border colour register w ........ nnnnnnnn in 8 bit mode w ........ nnnn.... in 4 bit mode 1fffec swm = selective write mask register w nnnnnnnn ........ mask 1fffee stm = selective mask register w ........ nnnnnnnn mask 1ffff0 a = source register a w nnnnnnnn nnnnnnnn source 1ffff2 b = destination register b rw nnnnnnnn nnnnnnnn destination 1ffff4 pcr = pixac command register w 1....... ........ 4N = 8/4 bits per pixel w .1....00 ....x00. COL = enable colour2 function w .1....00 .....01. COL = enable colour1 function w .1...0.. .....10. COL = enable bcolour2 function w .1...0.. .....11. COL = enable bcolour1 function w ..1..000 ....x00. EXC = enable exchange function w ..1..000 .....01. EXC = enable swap function w ..1..000 .....10. EXC = enable inverted exchange function w ..1..000 .....11. EXC = enable inverted swap function w ...1..0. ....x00. CPY = enable copy type b function w ...1...0 ....x10. CPY = enable copy type a function w ...1..0. .....01. CPY = enable patch type b function w ...1...0 .....11. CPY = enable patch type a function w ....1000 .....00. CMP = enable compare function w ....1000 .....10. CMP = enable compact function w .....1.. ........ RTL = manipulate right to left w ......1. ........ SHK = shrink picture by factor 2 w .......1 ........ ZOM = zoom picture by factor 2 w ........ nnnn.... LGF = logical function w ........ 0000.... LGF = d=r w ........ 0001.... LGF = d=~r w ........ 0010.... LGF = d=0 w ........ 0011.... LGF = d=1 w ........ 0100.... LGF = d=~(d^r) w ........ 0101.... LGF = d=d^r w ........ 0110.... LGF = d=d&r w ........ 0111.... LGF = d=~d&r w ........ 1000.... LGF = d=~d&~r w ........ 1001.... LGF = d=d&~r w ........ 1010.... LGF = d=~d|r w ........ 1011.... LGF = d=d|r w ........ 1100.... LGF = d=d|~r w ........ 1101.... LGF = d=~d|~r w ........ 1110.... LGF = d=d w ........ 1111.... LGF = d=~d w ........ ....1... INV = invert transparancy state of source bits w ........ .....1.. BIT = copy: enable copy type a w ........ .....1.. BIT = colour: enable bcolour/colour w ........ .....1.. BIT = compare: compact/compare w ........ ......1. TT = perform transparancy test w ........ .......0 1ffff6 mask = mask register w ........ ....nnnn mask nibbles/0 1ffff8 shift = shift register w ......nn ........ shift by .. during source alignment 1ffffa index = index register w ........ ......nn bcolour: use bit .. in the source word w ........ ......nn compact: nibble .. will hold the result 1ffffc fc/bc = foreground/background colour register w nnnnnnnn ........ FC = foreground colour w ........ nnnnnnnn BC = background colour 1ffffe tc = transparent colour register w nnnnnnnn ........ transparent colour end