tebl/RC6502-Apple-1-Replica

Nano Generated 1-MHz CPU Clock?

Opened this issue · 0 comments

Couldn't the Nano provide the 1-MHz CPU clock (running as a background task on the Nano)? Example code snippet;

 /***************************************************************************
  *  output 1-MHz clock on OC2A (D11/PB3) for RC6502 SBC                    *
  ***************************************************************************/
  void beginClock()
  { pinMode(11,OUTPUT);             // OC2A (D11/PB3)
 /*                                                                         *
  *  TCCR2A settings for 'normal' or 'CTC' (non-PWM) mode                   *
  *  ------------------------------------------------------------           *
  *  COM2A1:COM2A0 '01' - Toggle OC2A on Compare Match                      *
  *  WGM22:WGM20  '010' - CTC mode (clear timer on compare match)           *
  *                       (WGM22 bit is in TCCR2B register)                 *
  *                                                                         */
    TCCR2A = ((1 << WGM21) | (1 << COM2A0));
    TCCR2B = (1 << CS20);           // prescale = 1:1 (WGM22 = 0)
    TIMSK2 = 0;                     // no interrupts
    OCR2A = 7;                      // match value
  }                                 // 0/1/3/7 => 8/4/2/1 MHz
 /***************************************************************************/