Basic Sequencer for SWTPC 6809

Check out Look Mum No Computer's YouTube video featuring this project here!

Features

• Recording on four different channels
  • 3 synth channels, 1 drum channel
  • Five octaves supported (0-5V output with 1V/oct) on synth channels
  • 8 drums supported on drum channel, multiple drums played simultaneously
  • Switching between channels while recording
  • Switching between recording and playback
  • Clearing of channel while recording
  • Erasing of previously played note with .
  • Live preview of notes as they are recorded
• Playback of recorded sequence
• Clearing of entered channel data
• Changing tempo of playback
• Direct Control of channel instruments
• Manual entry of channel data

Input Configuration

• Menu keys are on bottom row of keyboard
• Synth Recording
  • Select channels with number keys
  • Piano keys starting on A, ending on ', with sharps and flats on W-P
  • Recording control on bottom row
    • Z to stop
    • M to change to playback
    • N to change recording channel
    • C to clear the current channel that is being recorded
• Drum Recording
  • Drums recorded with number keys 1-8
  • Multiple drums can be played in the same beat
  • Recording control on bottom row, same as synth recording
• Manual entry follows the same keys as recording
• Direct playback follows the same keys, but the only control key is stop

Configured Memory Map

• ROM Loaded at 0xE800
• SBug loaded at 0xF800
• Scratch RAM at 0x4000-0x4050
• Audio DAC at 0xE020-0xE023
• Drum channel at 0xE024 (one bit per drums)
• DAC gate at 0xE028 (one bit per channel, supports both synth and drum gates)
• MC6850 Serial Card

Sequencer in Action