A library that implements the UART receiver protocol for the RP2040 using PIO and a DMA buffer.
It is compatible with the SDK and Arduino.
How to use it:
- With SDK. Add uart_rx.pio, uart_rx.h and uart_rx.c to your project. Modify CMakeLists.txt. Add pico_generate_pio_header and the required libraries (pico_stdlib, hardware_irq, hardware_pio, hardware_dma). See CMakeLists.txt
- With Arduino. Add uart_rx.pio.h, uart_rx.h and uart_rx.c to your project
- Change UART_RX_IRQ_NUM if conflicts with other state machines irqs. Valid values 0 to 3.
Library parameters:
UART_RX_BUFFER_RING_BITS. Bit mask for the ring buffer. BUFFER_SIZE = 1 << UART_RX_BUFFER_RING_BITS
Functions:
void uart_rx_init(PIO pio, uint pin, uint baudrate)
Initialize the UART
Parameters:
pio - load the capture program at pio0 or pio1
pin - set receiver pin
baudrate - set the baudrate
void uart_rx_set_handler(uart_rx_handler_t handler, uint irq)
Set the interrupt handler
Parameters:
handler - function to handle bytes reception
irq - select the pio irq. Valid values for pio0: PIO0_IRQ_0, PIO0_IRQ_1 and for pio1: PIO1_IRQ_0, PIO1_IRQ_1. Useful if other states machines are also using irqs.
char uart_rx_read(void)
Returns:
A character from the buffer
char uart_rx_peek(void)
Returns:
A character from the buffer without removing it from the buffer
uint uart_rx_available(void)
Returns:
Available bytes from buffer
bool uart_rx_overflow(void)
Returns:
True if the buffer is overflown or false if not
void uart_rx_remove(void)
Reset handler, remove pio program from memory and free DMA channel
Handler functions:
void uart_rx_handler(void)
If the handler is defined, it is called when a character is received