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Diffstat (limited to 'libopencm3/lib/stm32/f0/usart.c')
| -rw-r--r-- | libopencm3/lib/stm32/f0/usart.c | 429 |
1 files changed, 429 insertions, 0 deletions
diff --git a/libopencm3/lib/stm32/f0/usart.c b/libopencm3/lib/stm32/f0/usart.c new file mode 100644 index 0000000..3788926 --- /dev/null +++ b/libopencm3/lib/stm32/f0/usart.c @@ -0,0 +1,429 @@ +/** @defgroup usart_file USART + * + * @ingroup STM32F0xx + * + * @brief <b>libopencm3 STM32F0xx USART</b> + * + * @version 1.0.0 + * + * @date 7 Jul 2013 + * + * LGPL License Terms @ref lgpl_license + */ + +/* + * This file is part of the libopencm3 project. + * + * This library is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this library. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <libopencm3/stm32/usart.h> +#include <libopencm3/stm32/rcc.h> + +/*---------------------------------------------------------------------------*/ +/** @brief USART Set Baudrate. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @param[in] baud unsigned 32 bit. Baud rate specified in Hz. + */ + +void usart_set_baudrate(uint32_t usart, uint32_t baud) +{ + uint32_t clock = rcc_ppre_frequency; + + if (usart == USART1) { + clock = rcc_ppre_frequency; + /* TODO selective PCLK, SYSCLK, HSI or LSE */ + } + + /* TODO check oversampling 16 */ + USART_BRR(usart) = ((2 * clock) + baud) / (2 * baud); +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Set Word Length. + * + * The word length is set to 8 or 9 bits. Note that the last bit will be a + * parity bit if parity is enabled, in which case the data length will be 7 + * or 8 bits respectively. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @param[in] bits unsigned 32 bit. Word length in bits 8 or 9. + */ + +void usart_set_databits(uint32_t usart, uint32_t bits) +{ + if (bits == 8) { + USART_CR1(usart) &= ~USART_CR1_M; /* 8 data bits */ + } else { + USART_CR1(usart) |= USART_CR1_M; /* 9 data bits */ + } +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Set Stop Bit(s). + * + * The stop bits are specified as 0.5, 1, 1.5 or 2. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @param[in] stopbits unsigned 32 bit. Stop bits @ref usart_cr2_stopbits. + */ + +void usart_set_stopbits(uint32_t usart, uint32_t stopbits) +{ + USART_CR2(usart) = (USART_CR2(usart) & ~USART_CR2_STOP) | stopbits; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Set Parity. + * + * The parity bit can be selected as none, even or odd. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @param[in] parity unsigned 32 bit. Parity @ref usart_cr1_parity. + */ + +void usart_set_parity(uint32_t usart, uint32_t parity) +{ + USART_CR1(usart) = (USART_CR1(usart) & ~USART_PARITY) | parity; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Set Rx/Tx Mode. + * + * The mode can be selected as Rx only, Tx only or Rx+Tx. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @param[in] mode unsigned 32 bit. Mode @ref usart_cr1_mode. + */ + +void usart_set_mode(uint32_t usart, uint32_t mode) +{ + USART_CR1(usart) = (USART_CR1(usart) & ~USART_MODE) | mode; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Set Hardware Flow Control. + * + * The flow control bit can be selected as none, RTS, CTS or RTS+CTS. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @param[in] flowcontrol unsigned 32 bit. Flowcontrol @ref + * usart_cr3_flowcontrol. + */ + +void usart_set_flow_control(uint32_t usart, uint32_t flowctrl) +{ + USART_CR3(usart) = (USART_CR3(usart) & ~USART_FLOWCONTROL) | flowctrl; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Enable. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_enable(uint32_t usart) +{ + USART_CR1(usart) |= USART_CR1_UE; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Disable. + * + * At the end of the current frame, the USART is disabled to reduce power. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_disable(uint32_t usart) +{ + USART_CR1(usart) &= ~USART_CR1_UE; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Send a Data Word. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @param[in] data unsigned 16 bit. + */ + +void usart_send(uint32_t usart, uint8_t data) +{ + USART_TDR(usart) = data; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Read a Received Data Word. + * + * If parity is enabled the MSB (bit 7 or 8 depending on the word length) is + * the parity bit. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @returns unsigned 16 bit data word. + */ + +uint8_t usart_recv(uint32_t usart) +{ + /* Receive data. */ + return USART_RDR(usart); +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Wait for Transmit Data Buffer Empty + * + * Blocks until the transmit data buffer becomes empty and is ready to accept + * the next data word. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_wait_send_ready(uint32_t usart) +{ + /* Wait until the data has been transferred into the shift register. */ + while ((USART_ISR(usart) & USART_ISR_TXE) == 0); +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Wait for Received Data Available + * + * Blocks until the receive data buffer holds a valid received data word. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_wait_recv_ready(uint32_t usart) +{ + /* Wait until the data is ready to be received. */ + while ((USART_ISR(usart) & USART_ISR_RXNE) == 0); +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Send Data Word with Blocking + * + * Blocks until the transmit data buffer becomes empty then writes the next + * data word for transmission. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @param[in] data unsigned 16 bit. + */ + +void usart_send_blocking(uint32_t usart, uint8_t data) +{ + usart_wait_send_ready(usart); + usart_send(usart, data); +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Read a Received Data Word with Blocking. + * + * Wait until a data word has been received then return the word. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @returns unsigned 16 bit data word. + */ + +uint8_t usart_recv_blocking(uint32_t usart) +{ + usart_wait_recv_ready(usart); + + return usart_recv(usart); +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Receiver DMA Enable. + * + * DMA is available on: + * @li USART1 Rx DMA1 channel 3 or 5. + * @li USART2 Rx DMA1 channel 5. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_enable_rx_dma(uint32_t usart) +{ + USART_CR3(usart) |= USART_CR3_DMAR; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Receiver DMA Disable. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_disable_rx_dma(uint32_t usart) +{ + USART_CR3(usart) &= ~USART_CR3_DMAR; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Transmitter DMA Enable. + * + * DMA is available on: + * @li USART1 Tx DMA1 channel 2 or 4. + * @li USART2 Tx DMA1 channel 4. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_enable_tx_dma(uint32_t usart) +{ + USART_CR3(usart) |= USART_CR3_DMAT; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Transmitter DMA Disable. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_disable_tx_dma(uint32_t usart) +{ + USART_CR3(usart) &= ~USART_CR3_DMAT; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Receiver Interrupt Enable. + +@param[in] usart unsigned 32 bit. USART block register address base @ref +usart_reg_base +*/ + +void usart_enable_rx_interrupt(uint32_t usart) +{ + USART_CR1(usart) |= USART_CR1_RXNEIE; +} + + +/*---------------------------------------------------------------------------*/ +/** @brief USART Receiver Interrupt Disable. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_disable_rx_interrupt(uint32_t usart) +{ + USART_CR1(usart) &= ~USART_CR1_RXNEIE; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Transmitter Interrupt Enable. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_enable_tx_interrupt(uint32_t usart) +{ + USART_CR1(usart) |= USART_CR1_TXEIE; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Transmitter Interrupt Disable. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_disable_tx_interrupt(uint32_t usart) +{ + USART_CR1(usart) &= ~USART_CR1_TXEIE; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Error Interrupt Enable. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_enable_error_interrupt(uint32_t usart) +{ + USART_CR3(usart) |= USART_CR3_EIE; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Error Interrupt Disable. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + */ + +void usart_disable_error_interrupt(uint32_t usart) +{ + USART_CR3(usart) &= ~USART_CR3_EIE; +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Read a Status Flag. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @param[in] flag Unsigned int32. Status register flag @ref usart_sr_flags. + * @returns boolean: flag set. + */ + +bool usart_get_flag(uint32_t usart, uint32_t flag) +{ + return ((USART_ISR(usart) & flag) != 0); +} + +/*---------------------------------------------------------------------------*/ +/** @brief USART Return Interrupt Source. + * + * Returns true if the specified interrupt flag (IDLE, RXNE, TC, TXE or OE) was + * set and the interrupt was enabled. If the specified flag is not an interrupt + * flag, the function returns false. + * + * @param[in] usart unsigned 32 bit. USART block register address base @ref + * usart_reg_base + * @param[in] flag Unsigned int32. Status register flag @ref usart_sr_flags. + * @returns boolean: flag and interrupt enable both set. + */ + +bool usart_get_interrupt_source(uint32_t usart, uint32_t flag) +{ + uint32_t flag_set = (USART_ISR(usart) & flag); + /* IDLE, RXNE, TC, TXE interrupts */ + if ((flag >= USART_ISR_IDLE) && (flag <= USART_ISR_TXE)) { + return ((flag_set & USART_CR1(usart)) != 0); + /* Overrun error */ + } else if (flag == USART_ISR_ORE) { + return flag_set && (USART_CR3(usart) & USART_CR3_CTSIE); + } + + return false; +} + +/**@}*/ + |