# Rust Embedded HAL for Apache NuttX RTOS
This crate provides Rust Embedded HAL interfaces (GPIO, I2C and SPI) for Apache NuttX RTOS.
For a sample NuttX Rust app, see [rust-i2c-nuttx](https://github.com/lupyuen/rust-i2c-nuttx)
If you find this crate useful, please support me on [GitHub Sponsors](https://github.com/sponsors/lupyuen)
# GPIO Output
```rust
// Open /dev/gpio1 for GPIO Output
let mut gpio = nuttx_embedded_hal::OutputPin
::new("/dev/gpio1")
.expect("open gpio failed");
// Set Chip Select to Low
gpio.set_low()
.expect("set gpio failed");
// Set Chip Select to High
gpio.set_high()
.expect("set gpio failed");
```
# GPIO Input
```rust
// Open /dev/gpio0 for GPIO Input
let gpio = nuttx_embedded_hal::InputPin
::new("/dev/gpio0")
.expect("open gpio failed");
```
# GPIO Interrupt
```rust
// Open /dev/gpio2 for GPIO Interrupt
let gpio = nuttx_hal::InterruptPin
::new("/dev/gpio2");
.expect("open gpio failed");
```
# I2C
```rust
// Open I2C Port /dev/i2c0
let mut i2c = nuttx_embedded_hal::I2c::new(
"/dev/i2c0", // I2C Port
400000, // I2C Frequency: 400 kHz
).expect("open failed");
// Buffer for received I2C data
let mut buf = [0 ; 1];
// Read register 0xD0 from I2C Address 0x77
i2c.write_read(
0x77, // I2C Address
&[0xD0], // Register ID
&mut buf // Buffer to be received
).expect("read register failed");
// Print the register value
println!("Register value is 0x{:02x}", buf[0]);
```
# SPI
The SPI interface requires the SPI Test Driver (/dev/spitest0) to be installed:
https://github.com/lupyuen/incubator-nuttx/tree/master/drivers/rf
```rust
// Open SPI Bus /dev/spitest0
let mut spi = nuttx_embedded_hal::Spi
::new("/dev/spitest0")
.expect("open spi failed");
// Open GPIO Output /dev/gpio1 for Chip Select
let mut cs = nuttx_embedded_hal::OutputPin
::new("/dev/gpio1")
.expect("open gpio failed");
// Set Chip Select to Low
cs.set_low()
.expect("cs failed");
// Transmit and receive SPI data
let mut data: [ u8; 5 ] = [ 0x1d, 0x00, 0x08, 0x00, 0x00 ];
spi.transfer(&mut data)
.expect("spi failed");
// Show the received SPI data
for i in 0..data.len() {
println!("{:02x}", data[i as usize]);
}
// Set Chip Select to High
cs.set_high()
.expect("cs failed");
```