295 lines
7.1 KiB
C
295 lines
7.1 KiB
C
/******************************************************************************
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* The MIT License
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*
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* Copyright (c) 2010 Perry Hung.
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy,
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* modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*****************************************************************************/
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/**
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* @file usart.c
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* @author Marti Bolivar <mbolivar@leaflabs.com>,
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* Perry Hung <perry@leaflabs.com>
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* @brief USART control routines
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*/
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#include "usart.h"
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#define USART_TX_IRQ
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/*
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* Devices
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*/
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static usart_dev usart1 = {
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.regs = USART1_BASE,
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.max_baud = 4500000UL,
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.clk_id = RCC_USART1,
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.irq_num = NVIC_USART1
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};
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/** USART1 device */
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usart_dev *USART1 = &usart1;
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static usart_dev usart2 = {
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.regs = USART2_BASE,
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.max_baud = 2250000UL,
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.clk_id = RCC_USART2,
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.irq_num = NVIC_USART2
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};
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/** USART2 device */
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usart_dev *USART2 = &usart2;
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static usart_dev usart3 = {
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.regs = USART3_BASE,
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.max_baud = 2250000UL,
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.clk_id = RCC_USART3,
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.irq_num = NVIC_USART3
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};
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/** USART3 device */
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usart_dev *USART3 = &usart3;
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#ifdef STM32_HIGH_DENSITY
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static usart_dev uart4 = {
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.regs = UART4_BASE,
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.max_baud = 2250000UL,
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.clk_id = RCC_UART4,
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.irq_num = NVIC_UART4
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};
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/** UART4 device */
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usart_dev *UART4 = &uart4;
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static usart_dev uart5 = {
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.regs = UART5_BASE,
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.max_baud = 2250000UL,
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.clk_id = RCC_UART5,
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.irq_num = NVIC_UART5
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};
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/** UART5 device */
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usart_dev *UART5 = &uart5;
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#endif
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/**
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* @brief Initialize a serial port.
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* @param dev Serial port to be initialized
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*/
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void usart_init(usart_dev *dev) {
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rb_init(&dev->rbRX, USART_RX_BUF_SIZE, dev->rx_buf);
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rb_init(&dev->rbTX, USART_TX_BUF_SIZE, dev->tx_buf);
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rcc_clk_enable(dev->clk_id);
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nvic_irq_enable(dev->irq_num);
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}
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/**
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* @brief Configure a serial port's baud rate.
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*
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* @param dev Serial port to be configured
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* @param clock_speed Clock speed, in megahertz.
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* @param baud Baud rate for transmit/receive.
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*/
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void usart_set_baud_rate(usart_dev *dev, uint32 baud) {
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uint32 integer_part;
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uint32 fractional_part;
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uint32 tmp;
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uint32 clock_speed = rcc_dev_clk_speed(dev->clk_id);
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/* See ST RM0008 for the details on configuring the baud rate register */
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integer_part = (25 * clock_speed) / (4 * baud);
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tmp = (integer_part / 100) << 4;
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fractional_part = integer_part - (100 * (tmp >> 4));
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tmp |= (((fractional_part * 16) + 50) / 100) & ((uint8)0x0F);
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dev->regs->BRR = (uint16)tmp;
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}
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/**
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* @brief Enable a serial port.
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*
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* USART is enabled in single buffer transmission mode, multibuffer
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* receiver mode, 8n1.
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*
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* Serial port must have a baud rate configured to work properly.
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*
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* @param dev Serial port to enable.
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* @see usart_set_baud_rate()
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*/
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void usart_enable(usart_dev *dev) {
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usart_reg_map *regs = dev->regs;
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regs->CR1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_RXNEIE;
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regs->CR1 |= USART_CR1_UE;
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}
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/**
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* @brief Enable serial port tx interrupt.
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*
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* @param dev Serial port.
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*/
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void usart_tx_irq_enable(usart_dev *dev) {
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bb_peri_set_bit(&dev->regs->CR1, USART_CR1_TXEIE_BIT, 1);
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}
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/**
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* @brief Disable serial port tx interrupt.
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*
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* @param dev Serial port.
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*/
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void usart_tx_irq_disable(usart_dev *dev) {
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bb_peri_set_bit(&dev->regs->CR1, USART_CR1_TXEIE_BIT, 0);
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}
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/**
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* @brief Turn off a serial port.
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* @param dev Serial port to be disabled
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*/
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void usart_disable(usart_dev *dev) {
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/* FIXME this misbehaves if you try to use PWM on TX afterwards */
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usart_reg_map *regs = dev->regs;
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// flush output buffer
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while(usart_data_pending(dev) > 0)
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;
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/* TC bit must be high before disabling the USART */
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while((regs->CR1 & USART_CR1_UE) && !(regs->SR & USART_SR_TC))
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;
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/* Disable UE */
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regs->CR1 &= ~USART_CR1_UE;
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/* Clean up buffer */
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usart_reset_rx(dev);
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}
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/**
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* @brief Call a function on each USART.
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* @param fn Function to call.
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*/
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void usart_foreach(void (*fn)(usart_dev*)) {
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fn(USART1);
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fn(USART2);
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fn(USART3);
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#ifdef STM32_HIGH_DENSITY
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fn(UART4);
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fn(UART5);
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#endif
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}
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/**
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* @brief Nonblocking USART transmit
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* @param dev Serial port to transmit over
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* @param buf Buffer to transmit
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* @param len Maximum number of bytes to transmit
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* @return Number of bytes transmitted
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*/
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uint32 usart_tx(usart_dev *dev, const uint8 *buf, uint32 len) {
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uint32 txed = 0;
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#ifdef USART_TX_IRQ
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while (txed < len && rb_safe_insert(&dev->rbTX, buf[txed])) {
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usart_tx_irq_enable(dev);
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txed++;
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}
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#else
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usart_reg_map *regs = dev->regs;
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while ((regs->SR & USART_SR_TXE) && (txed < len)) {
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regs->DR = buf[txed++];
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}
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#endif
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return txed;
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}
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/**
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* @brief Transmit an unsigned integer to the specified serial port in
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* decimal format.
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*
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* This function blocks until the integer's digits have been
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* completely transmitted.
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*
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* @param dev Serial port to send on
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* @param val Number to print
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*/
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void usart_putudec(usart_dev *dev, uint32 val) {
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char digits[12];
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int i = 0;
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do {
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digits[i++] = val % 10 + '0';
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val /= 10;
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} while (val > 0);
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while (--i >= 0) {
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usart_putc(dev, digits[i]);
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}
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}
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/*
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* Interrupt handlers.
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*/
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static inline void usart_irq(usart_dev *dev) {
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volatile int sr = dev->regs->SR;
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if(sr & USART_SR_RXNE) {
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#ifdef USART_SAFE_INSERT
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/* If the buffer is full and the user defines USART_SAFE_INSERT,
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* ignore new bytes. */
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rb_safe_insert(&dev->rbRX, (uint8)dev->regs->DR);
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#else
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/* By default, push bytes around in the ring buffer. */
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rb_push_insert(&dev->rbRX, (uint8)dev->regs->DR);
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#endif
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#ifdef USART_TX_IRQ
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} else if(sr & USART_SR_TXE) {
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if(rb_full_count(&dev->rbTX) > 0) {
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dev->regs->DR = rb_remove(&dev->rbTX);
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} else {
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usart_tx_irq_disable(dev); // disable tx irq
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// nops needed to deactivate the irq before irq handler is left
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asm volatile("nop");
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asm volatile("nop");
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}
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#endif
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}
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}
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void __irq_usart1(void) {
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usart_irq(USART1);
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}
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void __irq_usart2(void) {
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usart_irq(USART2);
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}
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void __irq_usart3(void) {
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usart_irq(USART3);
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}
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#ifdef STM32_HIGH_DENSITY
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void __irq_uart4(void) {
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usart_irq(UART4);
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}
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void __irq_uart5(void) {
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usart_irq(UART5);
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}
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#endif
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