I. Blackstomp Hardware

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I.1 Blackstomp Core (BSCORE) Module’s Physical Design Specification

Blackstomp core (BSCORE) module is designed to provide a standardized pinout for the main processing module, so it can be implemented with various type of generic processors which is available on the market. Figure 1 shows the physical design of the module in 2D drawing, and Figure 2 shows it in perspective drawing.

Figure 1. BSCORE Module Physical Design
Figure 2. 3D View of BSCORE Module

I.2 BSCORE Module’s Pinout Specification

  1. DC3V3: Power supply input +3.3V, mandatory
  2. DGND: Power, digital, and analog ground, mandatory
  3. TXD: UART (universal asynchronous receiver transmitter) data transmitter (3.3V level), mandatory
  4. RXD: UART (universal asynchronous receiver transmitter) data receiver (3.3V level), mandatory
  5. PROG1: Platform-agnostic programming pin (depends on the specific implementation), optional
  6. PROG2: Platform-agnostic programming pin (depends on the specific implementation), optional
  7. PROG3: Platform-agnostic programming pin (depends on the specific implementation), optional
  8. PROG4: Platform-agnostic programming pin (depends on the specific implementation), optional
  9. I2C-SCK: I2C clock (optional)
  10. I2C-SDA: I2C data (optional)
  11. LED1: Main indicator LED, mandatory
  12. LED2: Auxiliary indicator LED, mandatory
  13. D1: Digital input, mandatory
  14. D2: Digital input, mandatory
  15. D3: Digital input, mandatory
  16. D4: Digital input, optional
  17. A1: Analog input (0-3.3V), mandatory
  18. A2: Analog input (0-3.3V), mandatory
  19. A3: Analog input (0-3.3V), mandatory
  20. A4: Analog input (0-3.3V), mandatory
  21. A5: Analog input (0-3.3V), mandatory
  22. A6: Analog input (0-3.3V), mandatory
  23. OUT-L: Left output (line-level), mandatory
  24. OUT-R: Right output (line-level), mandatory
  25. IN-L: Left input (line-level), mandatory
  26. IN-R: Right input (line-level), mandatory
  27. MIC-P: Positive differential microphone input , mandatory
  28. MIC-N: Negative differential microphone input, mandatory
  29. AGND: Audio ground
  30. AGND: Audio ground

I.3 BSCORE Module’s Schematic Diagram

There are currently 2 variations of BSCORE implementation i.e. ESP32-A1S-AC101 version and ESP32-A1S-ES8388 version. We are working on ESP32 Wrover + WM8776 as the next variation for higher fidelity, and will be published here when it done. When working with ESP32-A1S, we have to identify whether it is the AC101 or ES8388 version because it has completely different pinout. Figure 3 show the different pinouts between both versions.

The Main Differences Between ESP32-A1S-AC101 and ESP32-A1S-ES8388 version of BSCORE Module

  • Audio codec: ESP32-A1S-AC101: AC101 chip, ESP32-A1S-ES8388: ES8388 chip
  • Microphone gain > ESP32-A1S-AC101: (0:0dB,1-7:30dB-48dB), ES8388: (0:0dB,1-8:3dB-24dB)
  • I2S interface > ESP32-A1S-AC101: available, ESP32-A1S-8388: not available
  • Available digital input > ESP32-A1S-AC101: (D1,D2,D3,D4), ESP32-A1S-8388: (D1,D2,D3)

Figure 3. AC101 Version and ES8388 Version of ESP32-A1S Module

BSCORE ESP32-A1S-AC101 Module’s Schematic Diagram

The schematic diagram of ESP32-A1S-AC101 BSCORE module is shown in the Figure 4. The PCB and its assembled module is shown in the Figure 5. There are two options to get the module:

  1. Download the gerber file here (free, even for commercial use) to fabricate your own PCB and assembly
  2. Buy the PCB or the assembled module from our store
Figure 4. BSCORE ESP32-A1S-AC101 Module Circuit Schematic Diagram
Figure 5. BSCORE ESP32-A1S-AC101 PCB and The Assembled Module

BSCORE ESP32-A1S-ES8388 Module’s Schematic Diagram

The schematic diagram of ESP32-A1S-ES8388 BSCORE module is shown in the Figure 6. The PCB and its assembled module is shown in the Figure 7. There are two options to get the module:

  1. Download the gerber file here (free, even for commercial use) to fabricate your own PCB and assembly
  2. Buy the PCB or the assembled module from our store
Figure 6. BSCORE ESP32-A1S-ES8388 Module Circuit Schematic Diagram
Figure 7. BSCORE ESP32-A1S-ES8388 PCB and The Assembled Module

I.4 BSCORE Development Mode Pedal Circuit Schematic Diagram

Development mode pedal enable convenient firmware reprogramming to speed up your new effect development and testing cycles. The pedal is designed to fit in 125B enclosure (Figure 11-Left), with the following features:

  1. Stereo Input
  2. Stereo output
  3. Microphone input
  4. MIDI input
  5. MIDI output
  6. Six control knobs
  7. Two foot switches
  8. Three indicator LEDs
  9. Firmware programming port

Figure 9 and 10 shows the complete schematic diagram of the pedal, so you can build the circuit on matrix board, design your own PCB, or using BSCORE dev pedal PCB designed by Deeptronic (available on our store).

Figure 8. BSCORE Development Mode Pedal Circuit Schematic Diagram
Figure 9. BSCORE Dev Pedal’s Off-board Parts Wiring Diagram
Figure 10. BSCORE Dev Pedal PCB (Available from Deeptronic Store)
Figure 11. Dev Pedal in 125B Enclosure (left), Assembled BSCORE Dev Pedal Board (Right-Upper), and BSCORE Module (Right-Lower)

I.5 BSCORE Generic Production Model-1 (BGPM-1) Pedal Circuit Schematic Diagram

BGPM-1 circuit enable low cost production for scale (from single to 100 pedal units) because it supports flexible arrangement of some control knobs. BGPM-1 PCB has 6 pads of knobs in 2 rows arrangement, designed for 125B enclosure. The first row can be mounted with potentiometers (up to 3 pots), while the second row can be mounted with pots, SPDT switch (2- or 3-position selector switch), or 1P8T rotary switch. The PCB support MIDI in/out function, stereo in/out, and microphone input. Just keep in mind that although it has microphone support, the available space doesn’t allow XLR socket for a standard microphone input. If you need a standard XLR input for microphone, you can use the Model-2 which has more space for the XLR socket since the PCB doesn’t has MIDI in/out support. Here is the schematic diagram (Figure 12):

Figure 12. BSCORE Generic Production Model-1 (BGPM-1) Schematic Diagram
Figure 13. BGPM-1 PCB (upper: top side, lower: bottom side)

Figure 13 shows the PCB for this circuit, it shows a double side design with component mounting and soldering in both side. This PCB is still already tested for PONG pedal (polyphonic octaver and noise grabber), and the gerber file download is available in this page: https://github.com/hamuro80/blackstomp/blob/master/hardware/Gerber_PCB_BGPM_1_V2.zip

I.6 BSCORE Generic Production Model-2 (BGPM-2) Circuit Schematic Diagram

BGPM-2 circuit is designed to provide enough space of an XLR socket for microphone input. It still has pads for 6 control knobs in 2-row arrangement, but the second row doesn’t support for potentiometers mounting . The support for MIDI in/out has been removed to provide the extra space needed for XLR socket mounting. Here is the schematic diagram (Figure 14):

Figure 14. BSCORE Generic Production Model-2 (BGPM-2) Schematic Diagram
Figure 15. BSCORE Generic Production Model-2 (BGPM-2) PCB

Figure 15 shows the PCB for the model-2 circuit, BGPM-2 PCB, it shows a double side design with component mounting and soldering in both side. This PCB has been tested for vocoder pedal application, and you can download the gerber file in this page (find the download button): https://github.com/hamuro80/blackstomp/blob/master/hardware/Gerber_PCB_BGPM_2_V2.zip

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