GPIO & hardware hacking
on your uConsole.

uConsole GPIO Header (back of device)
┌─────────────────────────────────────────────┐
│                                             │
│   Pin 11 (GPIO 17) ──── 330Ω ──── LED(+)   │
│                          resistor   anode   │
│                                     │       │
│   Pin 9  (GND) ──────────────── LED(-)      │
│                                  cathode    │
│                                             │
└─────────────────────────────────────────────┘

Physical connections:
  1. GPIO 17 (physical pin 11) → one leg of 330Ω resistor
  2. Other leg of resistor → LED anode (longer leg)
  3. LED cathode (shorter leg, flat side) → GND (physical pin 9)

  ┌──────┐    ┌─────┐    ┌─────┐
  │GPIO17├────┤330Ω ├────┤ LED ├────┐
  │Pin 11│    │     │    │ (+) │    │
  └──────┘    └─────┘    └──┬──┘    │
                            │       │
  ┌──────┐                  │       │
  │ GND  ├──────────────────┘       │
  │Pin 9 │      (cathode ─)        │
  └──────┘                          │
                                    │
  Current flow: GPIO17 → R → LED → GND

#!/usr/bin/env python3
"""LED blink on uConsole GPIO17 using libgpiod."""

import gpiod
import time
import sys

# Configuration
CHIP = "gpiochip0"
LED_PIN = 17          # BCM numbering
BLINK_INTERVAL = 0.5  # seconds

def main():
    # Open the GPIO chip
    chip = gpiod.Chip(CHIP)

    # Request the LED pin as output, default LOW
    config = gpiod.LineSettings(
        direction=gpiod.line.Direction.OUTPUT,
        output_value=gpiod.line.Value.INACTIVE,
    )
    request = chip.request_lines(
        consumer="led-blink",
        config={LED_PIN: config},
    )

    print(f"Blinking LED on GPIO {LED_PIN}...")
    print("Press Ctrl+C to stop.")

    try:
        while True:
            # Turn LED ON
            request.set_value(LED_PIN, gpiod.line.Value.ACTIVE)
            time.sleep(BLINK_INTERVAL)

            # Turn LED OFF
            request.set_value(LED_PIN, gpiod.line.Value.INACTIVE)
            time.sleep(BLINK_INTERVAL)

    except KeyboardInterrupt:
        print("\nStopped.")
    finally:
        # Release the line
        request.release()
        chip.close()

if __name__ == "__main__":
    main()

BME280 Sensor          uConsole GPIO Header
┌──────────┐          ┌──────────────────┐
│ VCC      ├──────────┤ Pin 1  (3.3V)    │
│ GND      ├──────────┤ Pin 9  (GND)     │
│ SDA      ├──────────┤ Pin 3  (GPIO 2)  │
│ SCL      ├──────────┤ Pin 5  (GPIO 3)  │
│ CSB      ├── NC     │                  │
│ SDO      ├── GND*   │                  │
└──────────┘          └──────────────────┘

* SDO pin sets I2C address:
  - SDO → GND  = address 0x76 (default)
  - SDO → VCC  = address 0x77

Only 4 wires needed: VCC, GND, SDA, SCL

# Enable SPI bus 0
dtparam=spi=on

# For specific SPI overlays (e.g., SPI display):
# dtoverlay=spi0-1cs   # Only one chip-select
# dtoverlay=spi0-2cs   # Two chip-selects (default)

SSD1306 OLED (128x64)    uConsole GPIO Header
┌──────────────┐        ┌──────────────────┐
│ VCC          ├────────┤ Pin 1  (3.3V)    │
│ GND          ├────────┤ Pin 6  (GND)     │
│ DIN (MOSI)   ├────────┤ Pin 19 (GPIO 10) │
│ CLK (SCLK)   ├────────┤ Pin 23 (GPIO 11) │
│ CS           ├────────┤ Pin 24 (GPIO 8)  │
│ DC           ├────────┤ Pin 18 (GPIO 24) │
│ RST          ├────────┤ Pin 22 (GPIO 25) │
└──────────────┘        └──────────────────┘

$ pip3 install luma.oled

# Quick test script
$ python3 -c "
from luma.core.interface.serial import spi
from luma.oled.device import ssd1306
from luma.core.render import canvas

serial = spi(device=0, port=0, gpio_DC=24, gpio_RST=25)
device = ssd1306(serial)

with canvas(device) as draw:
    draw.rectangle(device.bounding_box, outline='white')
    draw.text((10, 20), 'uConsole GPIO!', fill='white')
print('Display updated!')
"

uConsole GPIO Power Budget Calculator
═══════════════════════════════════════

3.3V Rail (max ~50mA available for GPIO):
  BME280 sensor        :   0.3 mA (sleep) / 1.0 mA (active)
  SSD1306 OLED (I2C)   :  10.0 mA
  Status LED (w/ 330Ω) :  10.0 mA
  ─────────────────────────────────
  Total 3.3V draw      :  21.0 mA  ✓ SAFE (42% of budget)

5V Rail (max ~300mA available via GPIO):
  Servo motor (SG90)   : 150.0 mA (stall)
  NeoPixel strip (5px) :  60.0 mA (full white)
  ─────────────────────────────────
  Total 5V draw        : 210.0 mA  ⚠ CAUTION (70% of budget)

Rules of thumb:
  ✓ Under 50% = comfortable headroom
  ⚠ 50-80%    = works but monitor for brownouts
  ✗ Over 80%  = use external power supply