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diff --git a/hardware/kicad/t-modem-s1224/README.md b/hardware/kicad/t-modem-s1224/README.md new file mode 100644 index 0000000..fc9b05a --- /dev/null +++ b/hardware/kicad/t-modem-s1224/README.md @@ -0,0 +1,67 @@ +# KiCad — T-Modem-s1224 + +Same PCB base as **T-Modem-c1224**, softmodem stuffing / metadata variant. + +| File | Role | +|------|------| +| `t-modem-s1224.kicad_sch` | Schematic (chip symbols **DNP**) | +| `t-modem-s1224.kicad_pcb` | PCB **180×180 mm** · **0** tracks · **0** vias | +| `t-modem-s1224.kicad_pro` | Project · `PROJECT=T-Modem-s1224` · `VERSION=1.0-upcoming1` | +| `t-modem-s1224.kicad_sym` | Symbols | +| `t-modem-s1224.rules` | Custom DRC rules | +| `t-modem-s1224.pre-strip-backup.kicad_pcb` | Pre first strip (289 segments) | +| `t-modem-s1224.2026-08-03-pre-reroute-backup.kicad_pcb` | Pre second strip / re-route reset (199 segments) | + +## Inventory — PCB footprints (**31**) + +**Keep:** U1 Pico · J_DC / U_REG / D_OR1 / F1 / C_BULK / C_BYP* / C_IN · J_AF · Q1 / R_PTT · J_LCD_I2C / U_LVL / RV2 · J_USB / J_USB_PICO · LED_* / R_LED* · SW1 / TP_BOOTSEL · H1–H4. + +**Removed (softmodem — not on PCB):** + +| Ref | Role | +|-----|------| +| **U_MODEM** / **SKT_MODEM** | TCM3105 + socket (sch **DNP** only) | +| **Y1** / **Y2** / **C_Y*** | Pierce (sch **DNP**) | +| **RV1** / **C_TX** / **C_RX** | Chip-era AF trim / coupling — **DNP** | +| **RV_CDL** / **R_TXR*** / **R_TRS** | Chip straps | + +## Schematic DNP (not stuffed) + +| Ref | Value | Flags | +|-----|-------|-------| +| **U_MODEM** | TCM3105 | `dnp` · `in_bom no` · `on_board no` | +| **Y1** | 4.4336 MHz | same | +| **Y2** | 6.5536 MHz | same | +| **D_OR2** | DNI-no-VBUS-OR | same (USB VBUS OR unused) | + +Tracks (`segment`): **0** — stripped 2026-08-03 for clean re-route. + +## U1 Pico AF nets (s1224 — no chip-era `MODEM_*` names) + +| Pad | GPIO | Net | Role | +|-----|------|-----|------| +| **9** | GP6 | **`AF_TX`** | PWM AFSK TX → radio AF inject | +| **10** | GP7 | *(NC)* | Unconnected on board | +| **11** | GP8 | *(NC)* | Unconnected on board | +| **31** | GP26 | **`AF_RX`** | ADC RX ← radio AF | +| **12** | GP9 | **`PTT_DRV`** | PTT keying | + +## Connector / power nets (pad names) + +| Ref | Nets | +|-----|------| +| **J_AF** | `AF_TX` · `AF_RX` · `PTT_OC` · `GND` | +| **J_DC** | `VIN_12` · `GND` ×2 | +| **F1** | `+5V_REG` → `+5V` | +| **D_OR1** | `+5V_OR` ← `+5V` | +| **Q1** / **R_PTT** | `PTT_DRV` → `PTT_B` → `PTT_OC` | + +No **`MODEM_*`** · **`TXA`** · **`RXA`** · **`TX_LVL`** on PCB. + +## Prototype AF wiring + +- **GP6** PWM AFSK out → `AF_TX` → radio inject +- **GP26** ADC0 ← `AF_RX` ← radio RX AF +- **GP9** PTT → `PTT_DRV` + +**AS-IS** · GPLv3 · non-profit. |