Baud Rate Generator

• Use timer 1 overflow to generate serial data clock

  • serial clock is 16x oversampled, i.e. baud rate x16
  • SMOD bit (PCON register)
    • 0: divides baud rate by 2

• Typical timer 1 setup

  • auto-reload timer
  • reload value determines overflow clock rate

• Baud rate calculation

  • Clocks between overflows = clocks
  • Overflow frequency =
  • Baud rate (assuming SMOD = 1)
  • Baud rate =
  • Max Baud rate =
  • TH1 value for 9600 baud =

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