Getting toward the end

Drama

We should have some drama today!

Otherwise, let’s look at a couple of things

• PWM: terminology and implementation
  • frequency, period, duration
  • Demonstration from Wolfram
  • bit banging PWM
    • void playTone(float frequencyHz, float durationS)
    • void playTone(int frequencyHz, long durationUS)
  • Music with PWM and interrupts
  • PWM with filters
• Computer Science “math”
  • Calculation Practice for CSCI 107 exam
  • Memories
  • Exponent rules at Khan Academcy
  • To enumerate n objects, you need log₂(n) bits
  • It just ain’t so
    • 8 M = 8²⁰
    • 8²⁰/2¹³ = 4⁷
  • What bit rate would be needed to generate 16-bit 44.1 kHz with PWM?
• MIPS32 implementation
  • Programming with only unconditional and conditional branches
  • MIPS 32 calling conventions
  • MIPS32 instructions
  • Arrays
  • Computing 1000*duration quickly
• C
  • C and Java bit-wise operators: &, |, ^, ~, << and >>
  • C logical operators
    • On input: 0 is false and anything but 0 is true
    • On output: 0 is false and 1 is true
  • C pointers and arrays
  • C pointers and structures