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/*
* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef _HARDWARE_UART_H
#define _HARDWARE_UART_H
#include "pico.h"
#include "hardware/structs/uart.h"
#include "hardware/regs/dreq.h"
// PICO_CONFIG: PARAM_ASSERTIONS_ENABLED_UART, Enable/disable assertions in the UART module, type=bool, default=0, group=hardware_uart
#ifndef PARAM_ASSERTIONS_ENABLED_UART
#define PARAM_ASSERTIONS_ENABLED_UART 0
#endif
#ifdef __cplusplus
extern "C" {
#endif
// PICO_CONFIG: PICO_UART_ENABLE_CRLF_SUPPORT, Enable/disable CR/LF translation support, type=bool, default=1, group=hardware_uart
#ifndef PICO_UART_ENABLE_CRLF_SUPPORT
#define PICO_UART_ENABLE_CRLF_SUPPORT 1
#endif
// PICO_CONFIG: PICO_UART_DEFAULT_CRLF, Enable/disable CR/LF translation on UART, type=bool, default=0, depends=PICO_UART_ENABLE_CRLF_SUPPORT, group=hardware_uart
#ifndef PICO_UART_DEFAULT_CRLF
#define PICO_UART_DEFAULT_CRLF 0
#endif
// PICO_CONFIG: PICO_DEFAULT_UART, Define the default UART used for printf etc, min=0, max=1, group=hardware_uart
// PICO_CONFIG: PICO_DEFAULT_UART_TX_PIN, Define the default UART TX pin, min=0, max=29, group=hardware_uart
// PICO_CONFIG: PICO_DEFAULT_UART_RX_PIN, Define the default UART RX pin, min=0, max=29, group=hardware_uart
// PICO_CONFIG: PICO_DEFAULT_UART_BAUD_RATE, Define the default UART baudrate, max=921600, default=115200, group=hardware_uart
#ifndef PICO_DEFAULT_UART_BAUD_RATE
#define PICO_DEFAULT_UART_BAUD_RATE 115200 ///< Default baud rate
#endif
/** \file hardware/uart.h
* \defgroup hardware_uart hardware_uart
*
* Hardware UART API
*
* RP2040 has 2 identical instances of a UART peripheral, based on the ARM PL011. Each UART can be connected to a number
* of GPIO pins as defined in the GPIO muxing.
*
* Only the TX, RX, RTS, and CTS signals are
* connected, meaning that the modem mode and IrDA mode of the PL011 are not supported.
*
* \subsection uart_example Example
* \addtogroup hardware_uart
*
* \code
* int main() {
*
* // Initialise UART 0
* uart_init(uart0, 115200);
*
* // Set the GPIO pin mux to the UART - 0 is TX, 1 is RX
* gpio_set_function(0, GPIO_FUNC_UART);
* gpio_set_function(1, GPIO_FUNC_UART);
*
* uart_puts(uart0, "Hello world!");
* }
* \endcode
*/
// Currently always a pointer to hw but it might not be in the future
typedef struct uart_inst uart_inst_t;
/** The UART identifiers for use in UART functions.
*
* e.g. uart_init(uart1, 48000)
*
* \ingroup hardware_uart
* @{
*/
#define uart0 ((uart_inst_t *)uart0_hw) ///< Identifier for UART instance 0
#define uart1 ((uart_inst_t *)uart1_hw) ///< Identifier for UART instance 1
/** @} */
#if !defined(PICO_DEFAULT_UART_INSTANCE) && defined(PICO_DEFAULT_UART)
#define PICO_DEFAULT_UART_INSTANCE (__CONCAT(uart,PICO_DEFAULT_UART))
#endif
#ifdef PICO_DEFAULT_UART_INSTANCE
#define uart_default PICO_DEFAULT_UART_INSTANCE
#endif
/*! \brief Convert UART instance to hardware instance number
* \ingroup hardware_uart
*
* \param uart UART instance
* \return Number of UART, 0 or 1.
*/
static inline uint uart_get_index(uart_inst_t *uart) {
invalid_params_if(UART, uart != uart0 && uart != uart1);
return uart == uart1 ? 1 : 0;
}
static inline uart_inst_t *uart_get_instance(uint instance) {
static_assert(NUM_UARTS == 2, "");
invalid_params_if(UART, instance >= NUM_UARTS);
return instance ? uart1 : uart0;
}
static inline uart_hw_t *uart_get_hw(uart_inst_t *uart) {
uart_get_index(uart); // check it is a hw uart
return (uart_hw_t *)uart;
}
/** \brief UART Parity enumeration
* \ingroup hardware_uart
*/
typedef enum {
UART_PARITY_NONE,
UART_PARITY_EVEN,
UART_PARITY_ODD
} uart_parity_t;
// ----------------------------------------------------------------------------
// Setup
/*! \brief Initialise a UART
* \ingroup hardware_uart
*
* Put the UART into a known state, and enable it. Must be called before other
* functions.
*
* This function always enables the FIFOs, and configures the UART for the
* following default line format:
*
* - 8 data bits
* - No parity bit
* - One stop bit
*
* \note There is no guarantee that the baudrate requested will be possible, the nearest will be chosen,
* and this function will return the configured baud rate.
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param baudrate Baudrate of UART in Hz
* \return Actual set baudrate
*/
uint uart_init(uart_inst_t *uart, uint baudrate);
/*! \brief DeInitialise a UART
* \ingroup hardware_uart
*
* Disable the UART if it is no longer used. Must be reinitialised before
* being used again.
*
* \param uart UART instance. \ref uart0 or \ref uart1
*/
void uart_deinit(uart_inst_t *uart);
/*! \brief Set UART baud rate
* \ingroup hardware_uart
*
* Set baud rate as close as possible to requested, and return actual rate selected.
*
* The UART is paused for around two character periods whilst the settings are
* changed. Data received during this time may be dropped by the UART.
*
* Any characters still in the transmit buffer will be sent using the new
* updated baud rate. uart_tx_wait_blocking() can be called before this
* function to ensure all characters at the old baud rate have been sent
* before the rate is changed.
*
* This function should not be called from an interrupt context, and the UART
* interrupt should be disabled before calling this function.
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param baudrate Baudrate in Hz
* \return Actual set baudrate
*/
uint uart_set_baudrate(uart_inst_t *uart, uint baudrate);
/*! \brief Set UART flow control CTS/RTS
* \ingroup hardware_uart
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param cts If true enable flow control of TX by clear-to-send input
* \param rts If true enable assertion of request-to-send output by RX flow control
*/
static inline void uart_set_hw_flow(uart_inst_t *uart, bool cts, bool rts) {
hw_write_masked(&uart_get_hw(uart)->cr,
(bool_to_bit(cts) << UART_UARTCR_CTSEN_LSB) | (bool_to_bit(rts) << UART_UARTCR_RTSEN_LSB),
UART_UARTCR_RTSEN_BITS | UART_UARTCR_CTSEN_BITS);
}
/*! \brief Set UART data format
* \ingroup hardware_uart
*
* Configure the data format (bits etc) for the UART.
*
* The UART is paused for around two character periods whilst the settings are
* changed. Data received during this time may be dropped by the UART.
*
* Any characters still in the transmit buffer will be sent using the new
* updated data format. uart_tx_wait_blocking() can be called before this
* function to ensure all characters needing the old format have been sent
* before the format is changed.
*
* This function should not be called from an interrupt context, and the UART
* interrupt should be disabled before calling this function.
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param data_bits Number of bits of data. 5..8
* \param stop_bits Number of stop bits 1..2
* \param parity Parity option.
*/
void uart_set_format(uart_inst_t *uart, uint data_bits, uint stop_bits, uart_parity_t parity);
/*! \brief Setup UART interrupts
* \ingroup hardware_uart
*
* Enable the UART's interrupt output. An interrupt handler will need to be installed prior to calling
* this function.
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param rx_has_data If true an interrupt will be fired when the RX FIFO contains data.
* \param tx_needs_data If true an interrupt will be fired when the TX FIFO needs data.
*/
static inline void uart_set_irq_enables(uart_inst_t *uart, bool rx_has_data, bool tx_needs_data) {
// Both UARTRXINTR (RX) and UARTRTINTR (RX timeout) interrupts are
// required for rx_has_data. RX asserts when >=4 characters are in the RX
// FIFO (for RXIFLSEL=0). RT asserts when there are >=1 characters and no
// more have been received for 32 bit periods.
uart_get_hw(uart)->imsc = (bool_to_bit(tx_needs_data) << UART_UARTIMSC_TXIM_LSB) |
(bool_to_bit(rx_has_data) << UART_UARTIMSC_RXIM_LSB) |
(bool_to_bit(rx_has_data) << UART_UARTIMSC_RTIM_LSB);
if (rx_has_data) {
// Set minimum threshold
hw_write_masked(&uart_get_hw(uart)->ifls, 0 << UART_UARTIFLS_RXIFLSEL_LSB,
UART_UARTIFLS_RXIFLSEL_BITS);
}
if (tx_needs_data) {
// Set maximum threshold
hw_write_masked(&uart_get_hw(uart)->ifls, 0 << UART_UARTIFLS_TXIFLSEL_LSB,
UART_UARTIFLS_TXIFLSEL_BITS);
}
}
/*! \brief Test if specific UART is enabled
* \ingroup hardware_uart
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \return true if the UART is enabled
*/
static inline bool uart_is_enabled(uart_inst_t *uart) {
return !!(uart_get_hw(uart)->cr & UART_UARTCR_UARTEN_BITS);
}
/*! \brief Enable/Disable the FIFOs on specified UART
* \ingroup hardware_uart
*
* The UART is paused for around two character periods whilst the settings are
* changed. Data received during this time may be dropped by the UART.
*
* Any characters still in the transmit FIFO will be lost if the FIFO is
* disabled. uart_tx_wait_blocking() can be called before this
* function to avoid this.
*
* This function should not be called from an interrupt context, and the UART
* interrupt should be disabled when calling this function.
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param enabled true to enable FIFO (default), false to disable
*/
void uart_set_fifo_enabled(uart_inst_t *uart, bool enabled);
// ----------------------------------------------------------------------------
// Generic input/output
/*! \brief Determine if space is available in the TX FIFO
* \ingroup hardware_uart
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \return false if no space available, true otherwise
*/
static inline bool uart_is_writable(uart_inst_t *uart) {
return !(uart_get_hw(uart)->fr & UART_UARTFR_TXFF_BITS);
}
/*! \brief Wait for the UART TX fifo to be drained
* \ingroup hardware_uart
*
* \param uart UART instance. \ref uart0 or \ref uart1
*/
static inline void uart_tx_wait_blocking(uart_inst_t *uart) {
while (uart_get_hw(uart)->fr & UART_UARTFR_BUSY_BITS) tight_loop_contents();
}
/*! \brief Determine whether data is waiting in the RX FIFO
* \ingroup hardware_uart
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \return true if the RX FIFO is not empty, otherwise false.
*
*/
static inline bool uart_is_readable(uart_inst_t *uart) {
// PL011 doesn't expose levels directly, so return values are only 0 or 1
return !(uart_get_hw(uart)->fr & UART_UARTFR_RXFE_BITS);
}
/*! \brief Write to the UART for transmission.
* \ingroup hardware_uart
*
* This function will block until all the data has been sent to the UART
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param src The bytes to send
* \param len The number of bytes to send
*/
static inline void uart_write_blocking(uart_inst_t *uart, const uint8_t *src, size_t len) {
for (size_t i = 0; i < len; ++i) {
while (!uart_is_writable(uart))
tight_loop_contents();
uart_get_hw(uart)->dr = *src++;
}
}
/*! \brief Read from the UART
* \ingroup hardware_uart
*
* This function blocks until len characters have been read from the UART
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param dst Buffer to accept received bytes
* \param len The number of bytes to receive.
*/
static inline void uart_read_blocking(uart_inst_t *uart, uint8_t *dst, size_t len) {
for (size_t i = 0; i < len; ++i) {
while (!uart_is_readable(uart))
tight_loop_contents();
*dst++ = (uint8_t) uart_get_hw(uart)->dr;
}
}
// ----------------------------------------------------------------------------
// UART-specific operations and aliases
/*! \brief Write single character to UART for transmission.
* \ingroup hardware_uart
*
* This function will block until the entire character has been sent
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param c The character to send
*/
static inline void uart_putc_raw(uart_inst_t *uart, char c) {
uart_write_blocking(uart, (const uint8_t *) &c, 1);
}
/*! \brief Write single character to UART for transmission, with optional CR/LF conversions
* \ingroup hardware_uart
*
* This function will block until the character has been sent
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param c The character to send
*/
static inline void uart_putc(uart_inst_t *uart, char c) {
#if PICO_UART_ENABLE_CRLF_SUPPORT
extern short uart_char_to_line_feed[NUM_UARTS];
if (uart_char_to_line_feed[uart_get_index(uart)] == c)
uart_putc_raw(uart, '\r');
#endif
uart_putc_raw(uart, c);
}
/*! \brief Write string to UART for transmission, doing any CR/LF conversions
* \ingroup hardware_uart
*
* This function will block until the entire string has been sent
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param s The null terminated string to send
*/
static inline void uart_puts(uart_inst_t *uart, const char *s) {
#if PICO_UART_ENABLE_CRLF_SUPPORT
bool last_was_cr = false;
while (*s) {
// Don't add extra carriage returns if one is present
if (last_was_cr)
uart_putc_raw(uart, *s);
else
uart_putc(uart, *s);
last_was_cr = *s++ == '\r';
}
#else
while (*s)
uart_putc(uart, *s++);
#endif
}
/*! \brief Read a single character from the UART
* \ingroup hardware_uart
*
* This function will block until a character has been read
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \return The character read.
*/
static inline char uart_getc(uart_inst_t *uart) {
char c;
uart_read_blocking(uart, (uint8_t *) &c, 1);
return c;
}
/*! \brief Assert a break condition on the UART transmission.
* \ingroup hardware_uart
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param en Assert break condition (TX held low) if true. Clear break condition if false.
*/
void uart_set_break(uart_inst_t *uart, bool en);
/*! \brief Set CR/LF conversion on UART
* \ingroup hardware_uart
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param translate If true, convert line feeds to carriage return on transmissions
*/
void uart_set_translate_crlf(uart_inst_t *uart, bool translate);
/*! \brief Wait for the default UART's TX FIFO to be drained
* \ingroup hardware_uart
*/
static inline void uart_default_tx_wait_blocking(void) {
#ifdef uart_default
uart_tx_wait_blocking(uart_default);
#else
assert(false);
#endif
}
/*! \brief Wait for up to a certain number of microseconds for the RX FIFO to be non empty
* \ingroup hardware_uart
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param us the number of microseconds to wait at most (may be 0 for an instantaneous check)
* \return true if the RX FIFO became non empty before the timeout, false otherwise
*/
bool uart_is_readable_within_us(uart_inst_t *uart, uint32_t us);
/*! \brief Return the DREQ to use for pacing transfers to/from a particular UART instance
* \ingroup hardware_uart
*
* \param uart UART instance. \ref uart0 or \ref uart1
* \param is_tx true for sending data to the UART instance, false for receiving data from the UART instance
*/
static inline uint uart_get_dreq(uart_inst_t *uart, bool is_tx) {
static_assert(DREQ_UART0_RX == DREQ_UART0_TX + 1, "");
static_assert(DREQ_UART1_RX == DREQ_UART1_TX + 1, "");
static_assert(DREQ_UART1_TX == DREQ_UART0_TX + 2, "");
return DREQ_UART0_TX + uart_get_index(uart) * 2 + !is_tx;
}
#ifdef __cplusplus
}
#endif
#endif