Connectors & pinouts (rev H)
Pin tables below follow the rev H netlist (toern_revH.net). Teensy pin names use the schematic global-label style (18_A4_SDA = digital pin 18 / A4 / SDA, etc.). The schematic PDF wins if a silk label disagrees.
For which jack is which on the finished box, see the handbook hardware page — this doc is the electrical map.
Panel audio / MIDI / USB
| Ref | Footprint (BOM) | Role |
|---|---|---|
| J4 | USB-C receptacle | Host USB (D+/D−, VBUS) |
| J1 | 6.35 mm Neutrik-style | Headphone out from SGTL5000 HP_L / HP_R / HP_VGND |
| J5 | 6.35 mm stereo TRS | Line out: tip → C17 → LINEOUT_L; ring → C16 → LINEOUT_R; sleeve GND |
| J6 | 6.35 mm stereo TRS | Line in: tip → C19 → LINEIN_L; ring → C18 → LINEIN_R; sleeve GND. Firmware records input channel 0 (left) only. |
| J7 | 6.35 mm | Mic / related input path (tip tied toward mic capsule net; sleeve GND) |
| J3, J17 | CUI SJ1-3533 (3.5 mm) | TRS MIDI in/out (opto / serial side via TLP2361 etc.) |
| MK1 | POM-2244P condenser | Built-in mic → codec MIC / MICBIAS path |
| J8 | Hirose microSD | SPI SD: CS=10, MOSI=11, MISO=12, SCK=13, VDD=+3.3V |
Exact silk labels on a built unit may use friendly names (LINE OUT, MIDI IN, …); match by connector family and position on the edge.
Power / speaker
| Ref | Type | Pins (PCB) |
|---|---|---|
| J16 | JST-PH 1×02 | 1 GND · 2 VBAT — LiPo |
| J10 | JST-PH 1×02 | Speaker outputs from PAM8403 (U13) |
| J9 | JST-PH 1×03 | Matrix / strip: pin 1 = Teensy 17 through R20 (220 Ω), pin 2 = GND, pin 3 = switched 5 V from TPS22918 U8 (enable is Teensy 36) |
| S1 | EG2219 slide switch | Main power path between charger system rail and +5V distribution |
Encoder sockets (I2C RGB encoders)
Several 1×05 pin sockets share the same bus (examples: J2, J18–J24):
| Pad | Net |
|---|---|
| 1 | GND |
| 2 | +5V |
| 3 | 18 SDA |
| 4 | 19 SCL |
| 5 | 27 — encoder interrupt (INT_PIN in firmware) |
These match Duppa / i2cEncoderLibV2-style modules used in firmware.
Analog clock / sidechain (JST-PH 1×02)
Silk on rev H. Pads: 1 = signal, 2 = GND.
| Silk | Ref | Teensy pin | Path |
|---|---|---|---|
| CLK-OUT(5V) | J25 | 37 | MCU → 74AHCT1G125 (U15, 5 V) → 1 kΩ → jack |
| CLK-IN(3-5V) | J26 | 38 | Jack → 22 kΩ → Schottky clamp (D2) → 74LVC1G17 Schmitt (U14, 3.3 V) → MCU |
| SIDEC-5V | J27 | 28 | MCU → 74AHCT1G125 (U16, 5 V) → 1 kΩ → jack |
Firmware: MENU → MIDI → PPQN drives J25 (rate / width / polarity / STOP). MENU → MIDI → CIN sets the J26 rate (1–32 PPQN) and hold-off. The pin-38 interrupt is attached only in BPM orange EXT and then calls playNote() / playFillNote() directly; fillTimer stays stopped, and playTimer only runs as a pulse-relocked one-shot that spaces the extra steps at 1/2 PPQN. D2 is BAT54S in standard SOT-23 (toern:BAT54S: pin 1 anode to GND, pin 2 cathode to +3.3 V, pin 3 common to the clamp node). Early rev H boards used KiCad D_Schottky_Dual_Series_ACK (pin 2 = common, pin 3 = cathode), which pulled U14's input to 3.3 V; those boards need D2 removed or bodged. MENU → MIDI → TRIG picks which voice pulses J27 (same width/polarity as PPQN; OFF disables).
Do not use J11 pin 31 for clock — that pad is unused GPIO.
Expansion JST-PH 1×05
| Ref | Pad 1 | Pad 2 | Pad 3 | Pad 4 | Pad 5 |
|---|---|---|---|---|---|
| J11 | 24 SCL2 | 25 SDA2 | 31 CTX3 | +3.3V | GND |
| J11.5 | 24 SCL2 | 25 SDA2 | 31 CTX3 | +5V | GND |
| J12 | 22 | 5 IN2 | 15 | +3.3V | GND |
| J13 | 2 OUT2 | 4 BCLK2 | 3 LRCLK2 | 6 | 39 |
| J14 | 14 | 9 | 16 | +3.3V | GND |
| J15 | 33 MCLK2 | 32 | 41 | +3.3V | GND |
J11 / J11.5 are I2C2 + pin 31 expansion, not the analog clock jacks (those are J25–J27 above).
Codec I²C
SGTL5000 (U3) control lines:
- SDA → Teensy
18 - SCL → Teensy
19
Same I²C bus as the encoder chain (distinct 7-bit addresses).
Schematic PDF
Full readable schematic: PCB/toern_revH/schematic.pdf.
Audio routing versus connector wiring
J1, J5 and J6 are stereo TRS connectors. Normal playback sends the main mono mix to both output channels; VOL → 2-CH can separate main/preview or sample banks. Those output mixers also feed USB audio. The current onboard recording path reads the left line-input channel only and writes mono WAVs. See Audio graph and the recording handbook.