Table of Contents
The Digital Sequencer
Schematic Overview:Sequencer
Inputs:
None
Outputs:
VoltageControlledOscillator: Note, Slide, EnvelopeGenerator: Gate, Accent MidiAndSync: Midi In, Midi Out, Sync In, Sync Out
The sequencer made up of 2 primary sections, the MicroProcessor and the IO system of the sequencer.
The Microprocessor and EPROM
Input Section
Switches
The input from the switches are sent to the 3 74hc165 ICs (IC16, IC17 and IC18) which are parallel to serial converters. The serial data is sent to the MicroProcessor via the SPL_OUT line. The output from IC16 is daisy chained to IC17, which is daisy chained to IC18.
| IC 17 | IC 18 | IC 16 | |||
|---|---|---|---|---|---|
| Switch | Function | Switch | Function | Switch | Function |
| 6 | Prev | 5 | Next | 14 | Done |
| 7 | C# | 15 | Run/Stop | 21 | G |
| 8 | D# | 16 | Chain | 22 | A |
| 9 | F# | 17 | C | 23 | B |
| 10 | G# | 18 | D | 24 | C |
| 11 | A# | 19 | E | 25 | Rest |
| 12 | Down | 20 | F | 26 | Accent |
| 13 | Up | (tempo switch) | 27 | Stop | |
Tempo
Rotary Switches
LEDs (Output Section)
The LEDs are controled by Serial input into 5 74hc595 ICs (IC4, IC5, IC6, IC7 and IC8) which are serial to parallel converters. They are daisychained like so: IC4 → IC5 → IC7 → IC6 → 1C8.
Note: The LEDs and resisitors need to be linked up to their respective ICs, however, it is difficult to descern which goes where from the schematic.
| LED | Resistor | - | LED | Resistor |
|---|---|---|---|---|
| 1 | 234 | - | 21 | 246 |
| 2 | 237 | - | 22 | 248 |
| 3 | 241 | - | 23 | 249 |
| 4 | 242 | - | 24 | 258 |
| 5 | 243 | - | 25 | 265 |
| 6 | 244 | - | 26 | 264 |
| 7 | 250 | - | 27 | 203 |
| 8 | 251 | - | 28 | 229 |
| 9 | 252 | - | 29 | 228 |
| 10 | 253 | - | 30 | 227 |
| 11 | 256 | - | 31 | 223 |
| 12 | 260 | - | 32 | 222 |
| 13 | 261 | - | 33 | 221 |
| 14 | 262 | - | 34 | 217 |
| 15 | 266 | - | 35 | 215 |
| 16 | 267 | - | 36 | 213 |
| 17 | 268 | - | 37 | 211 |
| 18 | 238 | - | 38 | 208 |
| 19 | 239 | - | 39 | 205 |
| 20 | 245 | - | 40 | 204 |
Thanks to Maxtim for providing these values
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