5E01

a fantasy sound chip created by Euly, based on the Ricoh 2A03, with some improvements:

• a 37.5% duty cycle,
• 32 noise pitches instead of 16, and
• triangle channel becomes a wave channel, with four available waveforms: triangle, saw, sine and square.

effects

• 11xx: write to delta modulation counter. range is 00 to 7F.
• this may be used to attenuate the triangle and noise channels; at 7F, they will be at about 57% volume.
• will not work if a sample is playing.
• 12xx: set duty cycle/noise mode/waveform of channel.
• may be 0 to 3 for the pulse channels:
  • 0: 12.5%
  • 1: 25%
  • 2: 37.5%
  • 3: 50%
• may be 0 or 1 for the noise channel:
  • 0: long (15-bit LFSR, 32767-step)
  • 1: short (9-bit LFSR, 93-step)
• may be 0 to 3 for the wave channel:
  • 0: triangle
  • 1: saw
  • 2: square
  • 3: sine
• 13xy: setup sweep up.
• x is the time.
• y is the shift.
• set to 0 to disable it.
• 14xy: setup sweep down.
• x is the time.
• y is the shift.
• set to 0 to disable it.
• 15xx: set envelope mode.
• 0: envelope + length counter. volume represents envelope duration.
• 1: length counter. volume represents output volume.
• 2: looping envelope. volume represents envelope duration.
• 3: constant volume. default value. volume represents output volume.
• pulse and noise channels only.
• you may need to apply a phase reset (using the macro) to make the envelope effective.
• 16xx: set length counter.
• see NES for more information.
• this will trigger phase reset.
• 17xx: set frame counter mode.
• 0: 4-step.
• 1: 5-step.
• 18xx: set PCM channel mode.
• 00: PCM (software).
• 01: DPCM (hardware).
• when in DPCM mode, samples will sound muffled (due to its nature), availables pitches are limited, and loop point is ignored.
• 19xx: set triangle linear counter.
• 00 to 7F set the counter.
• 80 and higher halt it.
• 20xx: set DPCM frequency.
• only works in DPCM mode.

info

this chip uses the NES instrument editor.

chip config

the following options are available in the Chip Manager window:

• Clock rate: sets the rate at which the chip will run.
• DPCM channel mode: allows you to set which mode to use for the DPCM channel.
• DPCM: the default mode, playing 1-bit DPCM samples as supported by the hardware.
• PCM: this mode provides crispier samples by writing the delta counter directly. uses a lot of CPU time in console.