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Text File  |  1998-10-24  |  3KB  |  57 lines
  1. DESKTOP ⑧x1k1
  2.                                 חללללללללללללללללל†
  3.                                 ´   DMA-FDC/HDC   ´
  4.                                 ´ bit assignments ´
  5.                                 זללללללללללללללללל¶
  6.                                  Atari Direct Memory Access for
  7.                                  Floppy Disk Controller and Hard Disk Controller
  8.               םגגגגגגגגגגגגגגגגג™
  9.               ø Status Register ø     b2=data requested
  10.               ø                 ø        0:no
  11.               ø                 ø        1:yes
  12.               ø                 ø     b1=sector counter equals zero
  13.               ø                 ø        0:yes
  14.               ø                 ø        1:no
  15.               ø                 ø     b0=error
  16.               ø                 ø        0:yes
  17.               ø                 ø        1:no
  18.               ijגגגגגגגגגגגגגגגגגך
  19.              םגגגגגגגגגגגגגגגגגג™
  20.              ø Control Register ø     b8=Read/Write
  21.              ø                  ø        0:read
  22.              ø                  ø        1:write
  23.              ø                  ø     b4=FDC-HDC/SC
  24.              ø                  ø        0:FDC-HDC
  25.              ø                  ø        1:sector counter
  26.              ø                  ø     b3=FDC/HDC
  27.              ø                  ø        0:FDC
  28.              ø                  ø        1:HDC
  29.              ø                  ø  b2-b1=[b1-b0]=FDC/HDC register
  30.              ø                  ø                00:FDC-SR/CR
  31.              ø                  ø                01:FDC-TKR
  32.              ø                  ø                10:FDC-SCR
  33.              ø                  ø                11:FDC-DTR
  34.              ijגגגגגגגגגגגגגגגגגגך
  35.  םגגגגגגגגגגגגגגגגגגגגגגגגגגגגגג™
  36.  ø Direct Memory Access Counter ø[b23-b0]=direct memory access counter
  37.  ø                              ø         (low-middle-high for writing)
  38.  ijגגגגגגגגגגגגגגגגגגגגגגגגגגגגגגך
  39.                םגגגגגגגגגגגגגגגג™
  40.                ø Sector Counter ø  b7-b0=sector counter
  41.                ø                ø        (1 sector=512 bytes)
  42.                ijגגגגגגגגגגגגגגגגך
  43.  
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  49.                            םגגגגגגגגגגגגגגגגגגגגגגגגג™
  50.                            ø           DMA           ø
  51.                            ø   םגגגגגגגגגגגגגגגגג™   ø
  52.                 םגגגגגגגג™ ø   ø 16 bytes buffer ø   ø  םגגגגגגגגג™ םגגגגגג™
  53.                 ø Memory בגגגגגדגגגגגגגגגגגגגגגגגדגגגגגגœ FDC/HDC בגœ Disk ø
  54.                 ijגגגגגגגגך ø   ø 16 bytes buffer ø   ø  ijגגגגגגגגגך ijגגגגגגך
  55.                            ø   ijגגגגגגגגגגגגגגגגגך   ø
  56.                            ijגגגגגגגגגגגגגגגגגגגגגגגגגך
  57.