1 files changed, 138 insertions, 0 deletions
diff --git a/libmaple/usart.c b/libmaple/usart.c
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+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Perry Hung.
+ * Copyright (c) 2011 LeafLabs, LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *****************************************************************************/
+
+/**
+ * @file libmaple/usart.c
+ * @author Marti Bolivar <mbolivar@leaflabs.com>,
+ *         Perry Hung <perry@leaflabs.com>
+ * @brief Portable USART routines
+ */
+
+#include <libmaple/usart.h>
+
+/**
+ * @brief Initialize a serial port.
+ * @param dev         Serial port to be initialized
+ */
+void usart_init(usart_dev *dev) {
+    rb_init(dev->rb, USART_RX_BUF_SIZE, dev->rx_buf);
+    rcc_clk_enable(dev->clk_id);
+    nvic_irq_enable(dev->irq_num);
+}
+
+/**
+ * @brief Enable a serial port.
+ *
+ * USART is enabled in single buffer transmission mode, multibuffer
+ * receiver mode, 8n1.
+ *
+ * Serial port must have a baud rate configured to work properly.
+ *
+ * @param dev Serial port to enable.
+ * @see usart_set_baud_rate()
+ */
+void usart_enable(usart_dev *dev) {
+    usart_reg_map *regs = dev->regs;
+    regs->CR1 = (USART_CR1_TE | USART_CR1_RE | USART_CR1_RXNEIE |
+                 USART_CR1_M_8N1);
+    regs->CR1 |= USART_CR1_UE;
+}
+
+/**
+ * @brief Turn off a serial port.
+ * @param dev Serial port to be disabled
+ */
+void usart_disable(usart_dev *dev) {
+    /* FIXME this misbehaves (on F1) if you try to use PWM on TX afterwards */
+    usart_reg_map *regs = dev->regs;
+
+    /* TC bit must be high before disabling the USART */
+    while((regs->CR1 & USART_CR1_UE) && !(regs->SR & USART_SR_TC))
+        ;
+
+    /* Disable UE */
+    regs->CR1 &= ~USART_CR1_UE;
+
+    /* Clean up buffer */
+    usart_reset_rx(dev);
+}
+
+/**
+ * @brief Nonblocking USART transmit
+ * @param dev Serial port to transmit over
+ * @param buf Buffer to transmit
+ * @param len Maximum number of bytes to transmit
+ * @return Number of bytes transmitted
+ */
+uint32 usart_tx(usart_dev *dev, const uint8 *buf, uint32 len) {
+    usart_reg_map *regs = dev->regs;
+    uint32 txed = 0;
+    while ((regs->SR & USART_SR_TXE) && (txed < len)) {
+        regs->DR = buf[txed++];
+    }
+    return txed;
+}
+
+/**
+ * @brief Nonblocking USART receive.
+ * @param dev Serial port to receive bytes from
+ * @param buf Buffer to store received bytes into
+ * @param len Maximum number of bytes to store
+ * @return Number of bytes received
+ */
+uint32 usart_rx(usart_dev *dev, uint8 *buf, uint32 len) {
+    uint32 rxed = 0;
+    while (usart_data_available(dev) && rxed < len) {
+        *buf++ = usart_getc(dev);
+        rxed++;
+    }
+    return rxed;
+}
+
+/**
+ * @brief Transmit an unsigned integer to the specified serial port in
+ *        decimal format.
+ *
+ * This function blocks until the integer's digits have been
+ * completely transmitted.
+ *
+ * @param dev Serial port to send on
+ * @param val Number to print
+ */
+void usart_putudec(usart_dev *dev, uint32 val) {
+    char digits[12];
+    int i = 0;
+
+    do {
+        digits[i++] = val % 10 + '0';
+        val /= 10;
+    } while (val > 0);
+
+    while (--i >= 0) {
+        usart_putc(dev, digits[i]);
+    }
+}