---
name: sketch-patterns
description: Canonical Arduino sketch templates for the Uno Q (blink, fade/PWM, button, analog read) and how to upload them. Load this whenever the user asks to write, run, upload, or flash a sketch, or asks for blink/fade/button/sensor code.
---

# Uno Q Sketch Patterns

Target the MCU with FQBN `arduino:zephyr:unoq`. Sketches are 3.3 V.

## Uploading

To run a sketch on the board, call the **`uno_q_flash`** tool with
`action` = `upload` and the full `.ino` in `code`. It compiles and flashes over
SWD. Do not describe the steps — emit the tool call.

## Blink (built-in LED, D13)

```cpp
void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
}
void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  delay(500);
  digitalWrite(LED_BUILTIN, LOW);
  delay(500);
}
```

## Fade (PWM — only D3, D5, D6, D9, D10, D11)

```cpp
const int PIN = 9;                  // must be a ~ PWM pin
void setup() { pinMode(PIN, OUTPUT); }
void loop() {
  for (int v = 0; v <= 255; v++) { analogWrite(PIN, v); delay(4); }
  for (int v = 255; v >= 0; v--) { analogWrite(PIN, v); delay(4); }
}
```

## Button (input with pull-up)

```cpp
const int BTN = 2;
void setup() {
  pinMode(BTN, INPUT_PULLUP);
  pinMode(LED_BUILTIN, OUTPUT);
}
void loop() {
  digitalWrite(LED_BUILTIN, digitalRead(BTN) == LOW ? HIGH : LOW);
}
```

## Analog read (0–3.3 V only!)

```cpp
void setup() { Serial.begin(115200); }
void loop() {
  int raw = analogRead(A0);           // 0..1023
  float volts = raw * 3.3 / 1023.0;   // NEVER exceed 3.3 V on A0-A5
  Serial.println(volts);
  delay(200);
}
```