8275

Programmable CRT controller

Pinout

         DIP40
         +---\/---+
     LC3 | 1    40| Vcc
     LC2 | 2    39| LA0
     LC1 | 3    38| LA1
     LC0 | 4    37| LTEN
     DRQ | 5    36| RVV
   *DACK | 6    35| Vsp
    HRTC | 7    34| GPA1
    VRTC | 8    33| GPA0
     *RD | 9    32| HLGT
     *WR |10    31| IRQ
    LPEN |11    30| CCLK
     DB0 |12    29| CC6
     DB1 |13    28| CC5
     DB2 |14    27| CC4
     DB3 |15    26| CC3
     DB4 |16    25| CC2
     DB5 |17    24| CC1
     DB6 |18    23| CC0
     DB7 |19    22| *CS
     GND |20    21| A0
         +--------+

Frequency

Set reader to FREQ, put black probe to GND, red probe to 30 to measure CPU clock

External links

8275 page on CPU-World

Files

• 
  8275 Datasheet