libopencm3
A free/libre/open-source firmware library for various ARM Cortex-M3 microcontrollers.
USART peripheral API
Collaboration diagram for USART peripheral API:

Functions

void usart_set_baudrate (uint32_t usart, uint32_t baud)
 USART Set Baudrate. More...
 
void usart_set_databits (uint32_t usart, uint32_t bits)
 USART Set Word Length. More...
 
void usart_set_stopbits (uint32_t usart, uint32_t stopbits)
 USART Set Stop Bit(s). More...
 
void usart_set_parity (uint32_t usart, uint32_t parity)
 USART Set Parity. More...
 
void usart_set_mode (uint32_t usart, uint32_t mode)
 USART Set Rx/Tx Mode. More...
 
void usart_set_flow_control (uint32_t usart, uint32_t flowcontrol)
 USART Set Hardware Flow Control. More...
 
void usart_enable (uint32_t usart)
 USART Enable. More...
 
void usart_disable (uint32_t usart)
 USART Disable. More...
 
void usart_send_blocking (uint32_t usart, uint16_t data)
 USART Send Data Word with Blocking. More...
 
uint16_t usart_recv_blocking (uint32_t usart)
 USART Read a Received Data Word with Blocking. More...
 
void usart_enable_rx_dma (uint32_t usart)
 USART Receiver DMA Enable. More...
 
void usart_disable_rx_dma (uint32_t usart)
 USART Receiver DMA Disable. More...
 
void usart_enable_tx_dma (uint32_t usart)
 USART Transmitter DMA Enable. More...
 
void usart_disable_tx_dma (uint32_t usart)
 USART Transmitter DMA Disable. More...
 
void usart_enable_rx_interrupt (uint32_t usart)
 USART Receiver Interrupt Enable. More...
 
void usart_disable_rx_interrupt (uint32_t usart)
 USART Receiver Interrupt Disable. More...
 
void usart_enable_tx_interrupt (uint32_t usart)
 USART Transmitter Interrupt Enable. More...
 
void usart_disable_tx_interrupt (uint32_t usart)
 USART Transmitter Interrupt Disable. More...
 
void usart_enable_tx_complete_interrupt (uint32_t usart)
 USART Transmission Complete Interrupt Enable. More...
 
void usart_disable_tx_complete_interrupt (uint32_t usart)
 USART Transmission Complete Interrupt Disable. More...
 
void usart_enable_idle_interrupt (uint32_t usart)
 USART Idle Interrupt Enable. More...
 
void usart_disable_idle_interrupt (uint32_t usart)
 USART Idle Interrupt Disable. More...
 
void usart_enable_error_interrupt (uint32_t usart)
 USART Error Interrupt Enable. More...
 
void usart_disable_error_interrupt (uint32_t usart)
 USART Error Interrupt Disable. More...
 
void usart_send (uint32_t usart, uint16_t data)
 USART Send a Data Word. More...
 
uint16_t usart_recv (uint32_t usart)
 USART Read a Received Data Word. More...
 
void usart_wait_send_ready (uint32_t usart)
 USART Wait for Transmit Data Buffer Empty. More...
 
void usart_wait_recv_ready (uint32_t usart)
 USART Wait for Received Data Available. More...
 
bool usart_get_flag (uint32_t usart, uint32_t flag)
 USART Read a Status Flag. More...
 

Detailed Description

Author
© 2009 Uwe Hermann uwe@h.nosp@m.erma.nosp@m.nn-uw.nosp@m.e.de

This library supports the USART/UART in the STM32F series of ARM Cortex Microcontrollers by ST Microelectronics.

Devices can have up to 3 USARTs and 2 UARTs.

Function Documentation

◆ usart_disable()

void usart_disable ( uint32_t  usart)

USART Disable.

At the end of the current frame, the USART is disabled to reduce power.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 205 of file usart_common_all.c.

References USART_CR1, and USART_CR1_UE.

◆ usart_disable_error_interrupt()

void usart_disable_error_interrupt ( uint32_t  usart)

USART Error Interrupt Disable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 421 of file usart_common_all.c.

References USART_CR3, and USART_CR3_EIE.

◆ usart_disable_idle_interrupt()

void usart_disable_idle_interrupt ( uint32_t  usart)

USART Idle Interrupt Disable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 397 of file usart_common_all.c.

References USART_CR1, and USART_CR1_IDLEIE.

◆ usart_disable_rx_dma()

void usart_disable_rx_dma ( uint32_t  usart)

USART Receiver DMA Disable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 269 of file usart_common_all.c.

References USART_CR3, and USART_CR3_DMAR.

◆ usart_disable_rx_interrupt()

void usart_disable_rx_interrupt ( uint32_t  usart)

USART Receiver Interrupt Disable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 324 of file usart_common_all.c.

References USART_CR1, and USART_CR1_RXNEIE.

◆ usart_disable_tx_complete_interrupt()

void usart_disable_tx_complete_interrupt ( uint32_t  usart)

USART Transmission Complete Interrupt Disable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 374 of file usart_common_all.c.

References USART_CR1, and USART_CR1_TCIE.

◆ usart_disable_tx_dma()

void usart_disable_tx_dma ( uint32_t  usart)

USART Transmitter DMA Disable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 299 of file usart_common_all.c.

References USART_CR3, and USART_CR3_DMAT.

◆ usart_disable_tx_interrupt()

void usart_disable_tx_interrupt ( uint32_t  usart)

USART Transmitter Interrupt Disable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 348 of file usart_common_all.c.

References USART_CR1, and USART_CR1_TXEIE.

◆ usart_enable()

void usart_enable ( uint32_t  usart)

USART Enable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 191 of file usart_common_all.c.

References USART_CR1, and USART_CR1_UE.

◆ usart_enable_error_interrupt()

void usart_enable_error_interrupt ( uint32_t  usart)

USART Error Interrupt Enable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 409 of file usart_common_all.c.

References USART_CR3, and USART_CR3_EIE.

◆ usart_enable_idle_interrupt()

void usart_enable_idle_interrupt ( uint32_t  usart)

USART Idle Interrupt Enable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 385 of file usart_common_all.c.

References USART_CR1, and USART_CR1_IDLEIE.

◆ usart_enable_rx_dma()

void usart_enable_rx_dma ( uint32_t  usart)

USART Receiver DMA Enable.

DMA is available on:

  • USART1 Rx DMA1 channel 5.
  • USART2 Rx DMA1 channel 6.
  • USART3 Rx DMA1 channel 3.
  • UART4 Rx DMA2 channel 3.
Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 257 of file usart_common_all.c.

References USART_CR3, and USART_CR3_DMAR.

◆ usart_enable_rx_interrupt()

void usart_enable_rx_interrupt ( uint32_t  usart)

USART Receiver Interrupt Enable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 311 of file usart_common_all.c.

References USART_CR1, and USART_CR1_RXNEIE.

◆ usart_enable_tx_complete_interrupt()

void usart_enable_tx_complete_interrupt ( uint32_t  usart)

USART Transmission Complete Interrupt Enable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 361 of file usart_common_all.c.

References USART_CR1, and USART_CR1_TCIE.

◆ usart_enable_tx_dma()

void usart_enable_tx_dma ( uint32_t  usart)

USART Transmitter DMA Enable.

DMA is available on:

  • USART1 Tx DMA1 channel 4.
  • USART2 Tx DMA1 channel 7.
  • USART3 Tx DMA1 channel 2.
  • UART4 Tx DMA2 channel 5.
Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 287 of file usart_common_all.c.

References USART_CR3, and USART_CR3_DMAT.

◆ usart_enable_tx_interrupt()

void usart_enable_tx_interrupt ( uint32_t  usart)

USART Transmitter Interrupt Enable.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 336 of file usart_common_all.c.

References USART_CR1, and USART_CR1_TXEIE.

◆ usart_get_flag()

bool usart_get_flag ( uint32_t  usart,
uint32_t  flag 
)

USART Read a Status Flag.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses
[in]flagUnsigned int32. Status register flag USART Status register Flags.
Returns
boolean: flag set.

Definition at line 108 of file usart_common_f124.c.

References USART_SR.

◆ usart_recv()

uint16_t usart_recv ( uint32_t  usart)

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.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses
Returns
unsigned 16 bit data word.

Definition at line 62 of file usart_common_f124.c.

References USART_DR, and USART_DR_MASK.

Referenced by usart_recv_blocking().

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◆ usart_recv_blocking()

uint16_t usart_recv_blocking ( uint32_t  usart)

USART Read a Received Data Word with Blocking.

Wait until a data word has been received then return the word.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses
Returns
unsigned 16 bit data word.

Definition at line 237 of file usart_common_all.c.

References usart_recv(), and usart_wait_recv_ready().

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◆ usart_send()

void usart_send ( uint32_t  usart,
uint16_t  data 
)

USART Send a Data Word.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses
[in]dataunsigned 16 bit.

Definition at line 45 of file usart_common_f124.c.

References USART_DR, and USART_DR_MASK.

Referenced by usart_send_blocking().

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◆ usart_send_blocking()

void usart_send_blocking ( uint32_t  usart,
uint16_t  data 
)

USART Send Data Word with Blocking.

Blocks until the transmit data buffer becomes empty then writes the next data word for transmission.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses
[in]dataunsigned 16 bit.

Definition at line 221 of file usart_common_all.c.

References usart_send(), and usart_wait_send_ready().

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◆ usart_set_baudrate()

void usart_set_baudrate ( uint32_t  usart,
uint32_t  baud 
)

USART Set Baudrate.

The baud rate is computed from the APB high-speed prescaler clock (for USART1/6) or the APB low-speed prescaler clock (for other USARTs). These values must be correctly set before calling this function (refer to the rcc_clock_setup-* functions in RCC).

Note: For LPUART, baudrates over 2**24 (~16.7 Mbaud) may overflow the calculation and are therefore not supported by this function.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses
[in]baudunsigned 32 bit. Baud rate specified in Hz.

Definition at line 53 of file usart_common_all.c.

References rcc_apb1_frequency, rcc_apb2_frequency, USART1, USART6, and USART_BRR.

◆ usart_set_databits()

void usart_set_databits ( uint32_t  usart,
uint32_t  bits 
)

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.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses
[in]bitsunsigned 32 bit. Word length in bits 8 or 9.

Definition at line 99 of file usart_common_all.c.

References USART_CR1, and USART_CR1_M.

◆ usart_set_flow_control()

void usart_set_flow_control ( uint32_t  usart,
uint32_t  flowcontrol 
)

USART Set Hardware Flow Control.

The flow control bit can be selected as none, RTS, CTS or RTS+CTS.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses
[in]flowcontrolunsigned 32 bit. Flowcontrol USART Hardware Flow Control Selection.

Definition at line 175 of file usart_common_all.c.

References USART_CR3, and USART_FLOWCONTROL_MASK.

◆ usart_set_mode()

void usart_set_mode ( uint32_t  usart,
uint32_t  mode 
)

USART Set Rx/Tx Mode.

The mode can be selected as Rx only, Tx only or Rx+Tx.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses
[in]modeunsigned 32 bit. Mode USART Tx/Rx Mode Selection.

Definition at line 156 of file usart_common_all.c.

References USART_CR1, and USART_MODE_MASK.

◆ usart_set_parity()

void usart_set_parity ( uint32_t  usart,
uint32_t  parity 
)

USART Set Parity.

The parity bit can be selected as none, even or odd.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses
[in]parityunsigned 32 bit. Parity USART Parity Selection.

Definition at line 137 of file usart_common_all.c.

References USART_CR1, and USART_PARITY_MASK.

◆ usart_set_stopbits()

void usart_set_stopbits ( uint32_t  usart,
uint32_t  stopbits 
)

USART Set Stop Bit(s).

The stop bits are specified as 0.5, 1, 1.5 or 2.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses
[in]stopbitsunsigned 32 bit. Stop bits USART Stop Bit Selection.

Definition at line 118 of file usart_common_all.c.

References USART_CR2, and USART_CR2_STOPBITS_MASK.

◆ usart_wait_recv_ready()

void usart_wait_recv_ready ( uint32_t  usart)

USART Wait for Received Data Available.

Blocks until the receive data buffer holds a valid received data word.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 93 of file usart_common_f124.c.

References USART_SR, and USART_SR_RXNE.

Referenced by usart_recv_blocking().

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◆ usart_wait_send_ready()

void usart_wait_send_ready ( uint32_t  usart)

USART Wait for Transmit Data Buffer Empty.

Blocks until the transmit data buffer becomes empty and is ready to accept the next data word.

Parameters
[in]usartunsigned 32 bit. USART block register address base USART register base addresses

Definition at line 78 of file usart_common_f124.c.

References USART_SR, and USART_SR_TXE.

Referenced by usart_send_blocking().

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