# `PWM` Module API Manual

## Overview

The K230 integrates two PWM hardware modules, each with three output channels. The output frequency of each module is adjustable, but the three channels share the same clock, while the duty cycle can be independently configured. Thus, channels 0, 1, and 2 share the same output frequency, and channels 3, 4, and 5 also share the same output frequency. For the I/O configuration of the channel outputs, refer to the IOMUX module.

## API Introduction

The `PWM` class is located in the `machine` module.

### Example Code

```python
import time
from machine import PWM, FPIOA

CONSTRUCT_WITH_FPIOA = False

PWM_CHANNEL = 0
PWM_PIN = 42
TEST_FREQ = 1000  # Hz

# Initialize PWM with 50% duty
try:
    if CONSTRUCT_WITH_FPIOA:
        # Use FPIOA to configure pin multiplexing for PWM, then pass the channel
        fpioa = FPIOA()
        fpioa.set_function(PWM_PIN, fpioa.PWM0 + PWM_CHANNEL)
        pwm = PWM(PWM_CHANNEL, freq=TEST_FREQ, duty=50)
    else:
        # Directly pass the pin number
        pwm = PWM(PWM_PIN, freq=TEST_FREQ, duty=50)
except Exception:
    print("FPIOA setup skipped or failed")

print("[INIT] freq: {}Hz, duty: {}%".format(pwm.freq(), pwm.duty()))
time.sleep(0.5)

# Test duty() getter and setter
print("[TEST] duty()")
pwm.duty(25)
print("Set duty to 25%, got:", pwm.duty(), "→ duty_u16:", pwm.duty_u16(), "→ duty_ns:", pwm.duty_ns())
time.sleep(0.2)

# Test duty_u16()
print("[TEST] duty_u16()")
pwm.duty_u16(32768)  # 50%
print("Set duty_u16 to 32768, got:", pwm.duty_u16(), "→ duty():", pwm.duty(), "→ duty_ns():", pwm.duty_ns())
time.sleep(0.2)

# Test duty_ns()
print("[TEST] duty_ns()")
period_ns = 1000000000 // pwm.freq()
duty_ns_val = (period_ns * 75) // 100  # 75%
pwm.duty_ns(duty_ns_val)
print("Set duty_ns to", duty_ns_val, "ns (≈75%), got:", pwm.duty_ns(), "→ duty():", pwm.duty(), "→ duty_u16():", pwm.duty_u16())
time.sleep(0.2)

# Change frequency and re-check duty values
print("[TEST] Change frequency to 500Hz")
pwm.freq(500)
print("New freq:", pwm.freq())
print("Duty after freq change → duty():", pwm.duty(), "→ duty_u16():", pwm.duty_u16(), "→ duty_ns():", pwm.duty_ns())
time.sleep(0.2)

# Clean up
pwm.deinit()
print("[DONE] PWM test completed")
```

### Constructor

```python
pwm = PWM(pin, freq=-1, duty=-1, duty_u16=-1, duty_ns=-1)
```

**Parameters**

- **`pin`**: Pin object or pin number. The driver automatically sets the pin to PWM multiplexing. For pin mappings, refer to [PWM Pin Multiplexing](#pwm-pin-multiplexing).
- **`freq`**: PWM output frequency (Hz). Default: `-1` (no change).
- **`duty`**: Duty cycle as a percentage of the period, range `[0, 100]`. Default: `-1` (no change).
- **`duty_ns`**: High-level duration in nanoseconds (`ns`). Default: `-1` (no change).
- **`duty_u16`**: High-level duration, range `[0, 65535]`. Default: `-1` (no change).

> Only one of `duty`, `duty_ns`, or `duty_u16` can be set at a time.

### `init` Method

```python
PWM.init(freq=-1, duty=-1, duty_u16=-1, duty_ns=-1)
```

**Parameters**

Same as [Constructor](#constructor).

### `deinit` Method

```python
PWM.deinit()
```

Release the PWM channel resources.

**Parameters**

None.

**Returns**

None.

### `freq` Method

```python
PWM.freq([freq])
```

Get or set the PWM output frequency.

**Parameters**

- **`freq`**: Optional. If provided, sets the frequency; otherwise, returns the current frequency.

**Returns**

Current frequency (if no argument) or `None`.

### `duty` Method

```python
PWM.duty([duty])
```

Get or set the duty cycle (percentage).

**Parameters**

- **`duty`**: Optional. If provided, sets the duty cycle; otherwise, returns the current value.

**Returns**

Current duty cycle (if no argument) or `None`.

### `duty_u16` Method

```python
PWM.duty_u16([duty_u16])
```

Get or set the duty cycle (16-bit value).

**Parameters**

- **`duty_u16`**: Optional. If provided, sets the duty cycle; otherwise, returns the current value.

**Returns**

Current duty cycle (if no argument) or `None`.

### `duty_ns` Method

```python
PWM.duty_ns([duty_ns])
```

Get or set the duty cycle (nanoseconds).

**Parameters**

- **`duty_ns`**: Optional. If provided, sets the duty cycle; otherwise, returns the current value.

**Returns**

Current duty cycle (if no argument) or `None`.

## PWM Pin Multiplexing

| PWM Channel | Available Pins          |
|-------------|-------------------------|
| PWM0        | GPIO42, GPIO54, GPIO60  |
| PWM1        | GPIO43, GPIO55, GPIO61  |
| PWM2        | GPIO7, GPIO46, GPIO56   |
| PWM3        | GPIO8, GPIO47, GPIO57   |
| PWM4        | GPIO9, GPIO52, GPIO58   |
| PWM5        | GPIO25, GPIO53, GPIO59  |