6845

CRT Controller (CRTC)

Pinout

DIP40
        +---\/---+
    Vss | 1    40| VSYNC
 *RESET | 2    39| HSYNC
  LPSTB | 3    38| RA0
    MA0 | 4    37| RA1
    MA1 | 5    36| RA2
    MA2 | 6    35| RA3
    MA3 | 7    34| RA4
    MA4 | 8    33| D0
    MA5 | 9    32| D1
    MA6 |10    31| D2
    MA7 |11    30| D3
    MA8 |12    29| D4
    MA9 |13    28| D5
   MA10 |14    27| D6
   MA11 |15    26| D7
   MA12 |16    25| *CS
   MA13 |17    24| RS
Dspl En |18    23| E
 CURSOR |19    22| R/*W
    Vcc |20    21| CLK
        +--------+

Frequency

Set reader to FREQ, put black probe to GND, red probe to 21 to measure CPU clock, to 39 for HSYNC and to 40 for VSYNC

External links

"6809 support chips" page on CPU-World

Files

• 

  MC6845 Datasheet