USART - Synchronous/Asynchronous Serial#
Universal Synchronous/Asynchronous Receiver/Transmitter Peripheral API.
The Universal Synchronous/Asynchronous Receiver/Transmitter (USART) is a very flexible serial I/O module. It supports full duplex asynchronous UART communication as well as RS-485, SPI, MicroWire, and 3-wire. It can also interface with ISO7816 Smart-Cards, and IrDA devices.
The USART has a wide selection of operating modes, frame formats, and baud rates. All features are supported through the API of this module.
Triple buffering and DMA support makes high data-rates possible with minimal CPU intervention. It is possible to transmit and receive large frames while the MCU remains in EM1 Sleep.
This module does not support DMA configuration. The UARTDRV and SPIDRV drivers provide full support for DMA and more.
The following steps are necessary for basic operation:
Clock enable:
#if !defined(_SILICON_LABS_32B_SERIES_2)
/* USART is a HFPERCLK peripheral. Enable HFPERCLK domain and USART0.
* We also need to enable the clock for GPIO to configure pins. */
CMU_ClockEnable(cmuClock_HFPER, true);
CMU_ClockEnable(cmuClock_USART0, true);
CMU_ClockEnable(cmuClock_GPIO, true);
#endif
To initialize the USART for asynchronous operation (e.g., UART):
/* Initialize with default settings and then update fields according to application requirements. */
USART_InitAsync_TypeDef initAsync = USART_INITASYNC_DEFAULT;
initAsync.baudrate = 38400;
USART_InitAsync(USART0, &initAsync);
To initialize the USART for synchronous operation (e.g., SPI):
/* Initialize with default settings and then update fields according to application requirements. */
USART_InitSync_TypeDef initSync = USART_INITSYNC_DEFAULT;
/* Operate as SPI master */
initSync.master = true;
/* Clock idle low, sample on falling edge. */
initSync.clockMode = usartClockMode1;
USART_InitSync(USART0, &initSync);
After pins are assigned for the application/board, enable pins at the desired location. Available locations can be obtained from the Pin Definitions section in the data sheet. Note
UARTDRV supports all types of UART flow control. Software assisted hardware flow control is available for parts without true UART hardware flow control.
Modules#
Enumerations#
Databit selection.
Enable selection.
Oversampling selection, used for asynchronous operation.
Parity selection, mainly used for asynchronous operation.
Stop bits selection, used for asynchronous operation.
Hardware Flow Control Selection.
Clock polarity/phase mode.
Pulse width selection for IrDA mode.
I2S format selection.
I2S frame data justify.
Typedefs#
PRS Channel type.
Functions#
Configure USART/UART operating in asynchronous mode to use a given baudrate (or as close as possible to a specified baudrate).
Calculate baudrate for USART/UART given reference frequency, clock division, and oversampling rate (if async mode).
Get the current baudrate for USART/UART.
Configure the USART operating in synchronous mode to use a given baudrate (or as close as possible to a specified baudrate).
Enable/disable USART/UART receiver and/or transmitter.
Initialize USART/UART for normal asynchronous mode.
Initialize USART for synchronous mode.
Initialize USART for asynchronous IrDA mode.
Initialize USART for I2S mode.
Initialize the automatic transmissions using PRS channel as a trigger.
Reset USART/UART to the same state that it was in after a hardware reset.
Receive one 4-8 bit frame, (or part of 10-16 bit frame).
Receive two 4-8 bit frames or one 10-16 bit frame.
Receive two 4-9 bit frames, or one 10-16 bit frame with extended information.
Receive one 4-9 bit frame (or part of 10-16 bit frame) with extended information.
Perform one 8 bit frame SPI transfer.
Transmit one 4-9 bit frame.
Transmit two 4-9 bit frames or one 10-16 bit frame.
Transmit two 4-9 bit frames or one 10-16 bit frame with extended control.
Transmit one 4-9 bit frame with extended control.
Clear one or more pending USART interrupts.
Disable one or more USART interrupts.
Enable one or more USART interrupts.
Get pending USART interrupt flags.
Get enabled and pending USART interrupt flags.
Set one or more pending USART interrupts from SW.
Get USART STATUS register.
Receive one 4-8 bit frame, (or part of 10-16 bit frame).
Receive two 4-8 bit frames, or one 10-16 bit frame.
Receive two 4-9 bit frames, or one 10-16 bit frame with extended information.
Receive one 4-9 bit frame, (or part of 10-16 bit frame) with extended information.
Macros#
Default configuration for USART asynchronous initialization structure.
Default configuration for USART PRS triggering structure.
Default configuration for USART sync initialization structure.
Default configuration for IrDA mode initialization structure.
Default configuration for I2S mode initialization structure.
Enumeration Documentation#
USART_Databits_TypeDef#
USART_Databits_TypeDef
Databit selection.
Enumerator | |
---|---|
usartDatabits4 | 4 data bits (not available for UART). |
usartDatabits5 | 5 data bits (not available for UART). |
usartDatabits6 | 6 data bits (not available for UART). |
usartDatabits7 | 7 data bits (not available for UART). |
usartDatabits8 | 8 data bits. |
usartDatabits9 | 9 data bits. |
usartDatabits10 | 10 data bits (not available for UART). |
usartDatabits11 | 11 data bits (not available for UART). |
usartDatabits12 | 12 data bits (not available for UART). |
usartDatabits13 | 13 data bits (not available for UART). |
usartDatabits14 | 14 data bits (not available for UART). |
usartDatabits15 | 15 data bits (not available for UART). |
usartDatabits16 | 16 data bits (not available for UART). |
97
of file platform/emlib/inc/em_usart.h
USART_Enable_TypeDef#
USART_Enable_TypeDef
Enable selection.
Enumerator | |
---|---|
usartDisable | Disable both receiver and transmitter. |
usartEnableRx | Enable receiver only, transmitter disabled. |
usartEnableTx | Enable transmitter only, receiver disabled. |
usartEnable | Enable both receiver and transmitter. |
114
of file platform/emlib/inc/em_usart.h
USART_OVS_TypeDef#
USART_OVS_TypeDef
Oversampling selection, used for asynchronous operation.
Enumerator | |
---|---|
usartOVS16 | 16x oversampling (normal). |
usartOVS8 | 8x oversampling. |
usartOVS6 | 6x oversampling. |
usartOVS4 | 4x oversampling. |
129
of file platform/emlib/inc/em_usart.h
USART_Parity_TypeDef#
USART_Parity_TypeDef
Parity selection, mainly used for asynchronous operation.
Enumerator | |
---|---|
usartNoParity | No parity. |
usartEvenParity | Even parity. |
usartOddParity | Odd parity. |
137
of file platform/emlib/inc/em_usart.h
USART_Stopbits_TypeDef#
USART_Stopbits_TypeDef
Stop bits selection, used for asynchronous operation.
Enumerator | |
---|---|
usartStopbits0p5 | 0.5 stop bits. |
usartStopbits1 | 1 stop bits. |
usartStopbits1p5 | 1.5 stop bits. |
usartStopbits2 | 2 stop bits. |
144
of file platform/emlib/inc/em_usart.h
USART_HwFlowControl_TypeDef#
USART_HwFlowControl_TypeDef
Hardware Flow Control Selection.
Enumerator | |
---|---|
usartHwFlowControlNone | No hardware flow control. |
usartHwFlowControlCts | CTS signal is enabled for TX flow control. |
usartHwFlowControlRts | RTS signal is enabled for RX flow control. |
usartHwFlowControlCtsAndRts | CTS and RTS signals are enabled for TX and RX flow control. |
166
of file platform/emlib/inc/em_usart.h
USART_ClockMode_TypeDef#
USART_ClockMode_TypeDef
Clock polarity/phase mode.
Enumerator | |
---|---|
usartClockMode0 | Clock idle low, sample on rising edge. |
usartClockMode1 | Clock idle low, sample on falling edge. |
usartClockMode2 | Clock idle high, sample on falling edge. |
usartClockMode3 | Clock idle high, sample on rising edge. |
179
of file platform/emlib/inc/em_usart.h
USART_IrDAPw_Typedef#
USART_IrDAPw_Typedef
Pulse width selection for IrDA mode.
Enumerator | |
---|---|
usartIrDAPwONE | IrDA pulse width is 1/16 for OVS=0 and 1/8 for OVS=1. |
usartIrDAPwTWO | IrDA pulse width is 2/16 for OVS=0 and 2/8 for OVS=1. |
usartIrDAPwTHREE | IrDA pulse width is 3/16 for OVS=0 and 3/8 for OVS=1. |
usartIrDAPwFOUR | IrDA pulse width is 4/16 for OVS=0 and 4/8 for OVS=1. |
194
of file platform/emlib/inc/em_usart.h
USART_I2sFormat_TypeDef#
USART_I2sFormat_TypeDef
I2S format selection.
Enumerator | |
---|---|
usartI2sFormatW32D32 | 32-bit word, 32-bit data. |
usartI2sFormatW32D24M | 32-bit word, 32-bit data with 8 lsb masked. |
usartI2sFormatW32D24 | 32-bit word, 24-bit data. |
usartI2sFormatW32D16 | 32-bit word, 16-bit data. |
usartI2sFormatW32D8 | 32-bit word, 8-bit data. |
usartI2sFormatW16D16 | 16-bit word, 16-bit data. |
usartI2sFormatW16D8 | 16-bit word, 8-bit data. |
usartI2sFormatW8D8 | 8-bit word, 8-bit data. |
265
of file platform/emlib/inc/em_usart.h
USART_I2sJustify_TypeDef#
USART_I2sJustify_TypeDef
I2S frame data justify.
Enumerator | |
---|---|
usartI2sJustifyLeft | Data is left-justified within the frame. |
usartI2sJustifyRight | Data is right-justified within the frame. |
277
of file platform/emlib/inc/em_usart.h
Typedef Documentation#
USART_PRS_Channel_t#
typedef uint8_t USART_PRS_Channel_t
PRS Channel type.
209
of file platform/emlib/inc/em_usart.h
Function Documentation#
USART_BaudrateAsyncSet#
void USART_BaudrateAsyncSet (USART_TypeDef * usart, uint32_t refFreq, uint32_t baudrate, USART_OVS_TypeDef ovs)
Configure USART/UART operating in asynchronous mode to use a given baudrate (or as close as possible to a specified baudrate).
[in] | usart | A pointer to the USART/UART peripheral register block. |
[in] | refFreq | USART/UART reference clock frequency in Hz. If set to 0, the currently configured reference clock is assumed. |
[in] | baudrate | Baudrate to try to achieve for USART/UART. |
[in] | ovs | Oversampling to be used. Normal is 16x oversampling but lower oversampling may be used to achieve higher rates or better baudrate accuracy in some cases. Notice that lower oversampling frequency makes the channel more vulnerable to bit faults during reception due to clock inaccuracies compared to the link partner. |
313
of file platform/emlib/src/em_usart.c
USART_BaudrateCalc#
uint32_t USART_BaudrateCalc (uint32_t refFreq, uint32_t clkdiv, bool syncmode, USART_OVS_TypeDef ovs)
Calculate baudrate for USART/UART given reference frequency, clock division, and oversampling rate (if async mode).
[in] | refFreq | USART/UART HF peripheral frequency used. |
[in] | clkdiv | A clock division factor to be used. |
[in] | syncmode |
|
[in] | ovs | Oversampling used if in asynchronous mode. Not used if |
This function returns the baudrate that a USART/UART module will use if configured with the given frequency, clock divisor, and mode. Notice that this function will not use the hardware configuration. It can be used to determine if a given configuration is sufficiently accurate for the application.
Returns
Baudrate with given settings.
455
of file platform/emlib/src/em_usart.c
USART_BaudrateGet#
uint32_t USART_BaudrateGet (USART_TypeDef * usart)
Get the current baudrate for USART/UART.
[in] | usart | A pointer to the USART/UART peripheral register block. |
This function returns the actual baudrate (not considering oscillator inaccuracies) used by a USART/UART peripheral.
Returns
The current baudrate.
586
of file platform/emlib/src/em_usart.c
USART_BaudrateSyncSet#
void USART_BaudrateSyncSet (USART_TypeDef * usart, uint32_t refFreq, uint32_t baudrate)
Configure the USART operating in synchronous mode to use a given baudrate (or as close as possible to a specified baudrate).
[in] | usart | A pointer to the USART peripheral register block. (Cannot be used on UART modules.) |
[in] | refFreq | A USART reference clock frequency in Hz that will be used. If set to 0, the currently-configured reference clock is assumed. |
[in] | baudrate | Baudrate to try to achieve for USART. |
The configuration will be set to use a baudrate <= the specified baudrate to ensure that the baudrate does not exceed the specified value.
The fractional clock division is suppressed, although the hardware design allows it. It could cause half clock cycles to exceed a specified limit and thus potentially violate specifications for the slave device. In some special situations, a fractional clock division may be useful even in synchronous mode, but in those cases it must be directly adjusted, possibly assisted by USART_BaudrateCalc():
Warnings
The consequence of the aforementioned suppression of the fractional part of the clock divider is that some frequencies won't be achievable. The divider will only be able to be an integer value so the reference clock will only be dividable by N (where N is a positive integer).
649
of file platform/emlib/src/em_usart.c
USART_Enable#
void USART_Enable (USART_TypeDef * usart, USART_Enable_TypeDef enable)
Enable/disable USART/UART receiver and/or transmitter.
[in] | usart | A pointer to the USART/UART peripheral register block. |
[in] | enable | Select the status for the receiver/transmitter. |
Notice that this function does not do any configuration. Enabling should normally be done after initialization (if not enabled as part of initialization).
711
of file platform/emlib/src/em_usart.c
USART_InitAsync#
void USART_InitAsync (USART_TypeDef * usart, const USART_InitAsync_TypeDef * init)
Initialize USART/UART for normal asynchronous mode.
[in] | usart | A pointer to the USART/UART peripheral register block. |
[in] | init | A pointer to the initialization structure used to configure the basic async setup. |
This function will configure basic settings to operate in normal asynchronous mode.
A special control setup not covered by this function must be done after using this function by direct modification of the CTRL register.
Notice that pins used by the USART/UART module must be properly configured by the user explicitly for the USART/UART to work as intended. (When configuring pins, remember to consider the sequence of configuration to avoid unintended pulses/glitches on output pins.)
762
of file platform/emlib/src/em_usart.c
USART_InitSync#
void USART_InitSync (USART_TypeDef * usart, const USART_InitSync_TypeDef * init)
Initialize USART for synchronous mode.
[in] | usart | A pointer to the USART peripheral register block. (UART does not support this mode.) |
[in] | init | A pointer to the initialization structure used to configure basic async setup. |
This function will configure basic settings to operate in synchronous mode.
A special control setup not covered by this function must be done after using this function by direct modification of the CTRL register.
Notice that pins used by the USART module must be properly configured by the user explicitly for the USART to work as intended. (When configuring pins remember to consider the sequence of configuration to avoid unintended pulses/glitches on output pins.)
870
of file platform/emlib/src/em_usart.c
USARTn_InitIrDA#
void USARTn_InitIrDA (USART_TypeDef * usart, const USART_InitIrDA_TypeDef * init)
Initialize USART for asynchronous IrDA mode.
[in] | usart | A pointer to the USART peripheral register block. |
[in] | init | A pointer to the initialization structure used to configure async IrDA setup. |
This function will configure basic settings to operate in asynchronous IrDA mode.
A special control setup not covered by this function must be done after using this function by direct modification of the CTRL and IRCTRL registers.
Notice that pins used by the USART/UART module must be properly configured by the user explicitly for the USART/UART to work as intended. (When configuring pins, remember to consider the sequence of configuration to avoid unintended pulses/glitches on output pins.)
Note
Not all USART instances support IrDA. See the data sheet for your device.
954
of file platform/emlib/src/em_usart.c
USART_InitI2s#
void USART_InitI2s (USART_TypeDef * usart, USART_InitI2s_TypeDef * init)
Initialize USART for I2S mode.
[in] | usart | A pointer to the USART peripheral register block. (UART does not support this mode.) |
[in] | init | A pointer to the initialization structure used to configure the basic I2S setup. |
This function will configure basic settings to operate in I2S mode.
A special control setup not covered by this function must be done after using this function by direct modification of the CTRL and I2SCTRL registers.
Notice that pins used by the USART module must be properly configured by the user explicitly for the USART to work as intended. (When configuring pins, remember to consider the sequence of configuration to avoid unintended pulses/glitches on output pins.)
Note
This function does not apply to all USART's. See the chip Reference Manual.
1013
of file platform/emlib/src/em_usart.c
USART_InitPrsTrigger#
void USART_InitPrsTrigger (USART_TypeDef * usart, const USART_PrsTriggerInit_TypeDef * init)
Initialize the automatic transmissions using PRS channel as a trigger.
[in] | usart | A pointer to USART to configure. |
[in] | init | A pointer to the initialization structure. |
Note
Initialize USART with USART_Init() before setting up the PRS configuration.
1053
of file platform/emlib/src/em_usart.c
USART_Reset#
void USART_Reset (USART_TypeDef * usart)
Reset USART/UART to the same state that it was in after a hardware reset.
[in] | usart | A pointer to USART/UART peripheral register block. |
1087
of file platform/emlib/src/em_usart.c
USART_Rx#
uint8_t USART_Rx (USART_TypeDef * usart)
Receive one 4-8 bit frame, (or part of 10-16 bit frame).
[in] | usart | A pointer to the USART/UART peripheral register block. |
This function is normally used to receive one frame when operating with frame length 4-8 bits. See USART_RxExt() for reception of 9 bit frames.
Notice that possible parity/stop bits in asynchronous mode are not considered part of a specified frame bit length.
Note
This function will stall if the buffer is empty until data is received. Alternatively, the user can explicitly check whether data is available. If data is available, call USART_RxDataGet() to read the RXDATA register directly.
Returns
Data received.
1182
of file platform/emlib/src/em_usart.c
USART_RxDouble#
uint16_t USART_RxDouble (USART_TypeDef * usart)
Receive two 4-8 bit frames or one 10-16 bit frame.
[in] | usart | A pointer to the USART/UART peripheral register block. |
This function is normally used to receive one frame when operating with frame length 10-16 bits. See USART_RxDoubleExt() for reception of two 9 bit frames.
Notice that possible parity/stop bits in asynchronous mode are not considered part of a specified frame bit length.
Note
This function will stall if the buffer is empty until data is received. Alternatively, the user can explicitly check whether data is available. If data is available, call USART_RxDoubleGet() to read the RXDOUBLE register directly.
Returns
Data received.
1214
of file platform/emlib/src/em_usart.c
USART_RxDoubleExt#
uint32_t USART_RxDoubleExt (USART_TypeDef * usart)
Receive two 4-9 bit frames, or one 10-16 bit frame with extended information.
[in] | usart | A pointer to the USART/UART peripheral register block. |
This function is normally used to receive one frame when operating with frame length 10-16 bits and additional RX status information is required.
Notice that possible parity/stop bits in asynchronous mode are not considered part of a specified frame bit length.
Note
This function will stall if buffer is empty until data is received. Alternatively, the user can explicitly check whether data is available. If data is available, call USART_RxDoubleXGet() to read the RXDOUBLEX register directly.
Returns
Data received.
1246
of file platform/emlib/src/em_usart.c
USART_RxExt#
uint16_t USART_RxExt (USART_TypeDef * usart)
Receive one 4-9 bit frame (or part of 10-16 bit frame) with extended information.
[in] | usart | A pointer to the USART/UART peripheral register block. |
This function is normally used to receive one frame when operating with frame length 4-9 bits and additional RX status information is required.
Notice that possible parity/stop bits in asynchronous mode are not considered part of a specified frame bit length.
Note
This function will stall if the buffer is empty until data is received. Alternatively, the user can explicitly check whether data is available. If data is available, call USART_RxDataXGet() to read the RXDATAX register directly.
Returns
Data received.
1278
of file platform/emlib/src/em_usart.c
USART_SpiTransfer#
uint8_t USART_SpiTransfer (USART_TypeDef * usart, uint8_t data)
Perform one 8 bit frame SPI transfer.
[in] | usart | A pointer to the USART peripheral register block. |
[in] | data | Data to transmit. |
Note
This function will stall if the transmit buffer is full. When a transmit buffer becomes available, data is written and the function will wait until data is fully transmitted. The SPI return value is then read out and returned.
Returns
Data received.
1305
of file platform/emlib/src/em_usart.c
USART_Tx#
void USART_Tx (USART_TypeDef * usart, uint8_t data)
Transmit one 4-9 bit frame.
[in] | usart | A pointer to the USART/UART peripheral register block. |
[in] | data | Data to transmit. See details above for more information. |
Depending on the frame length configuration, 4-8 (least significant) bits from data
are transmitted. If the frame length is 9, 8 bits are transmitted from data
and one bit as specified by CTRL register, BIT8DV field. See USART_TxExt() for transmitting 9 bit frame with full control of all 9 bits.
Notice that possible parity/stop bits in asynchronous mode are not considered part of a specified frame bit length.
Note
This function will stall if the buffer is full until the buffer becomes available.
1338
of file platform/emlib/src/em_usart.c
USART_TxDouble#
void USART_TxDouble (USART_TypeDef * usart, uint16_t data)
Transmit two 4-9 bit frames or one 10-16 bit frame.
[in] | usart | A pointer to the USART/UART peripheral register block. |
[in] | data | Data to transmit, the least significant byte holds the frame transmitted first. See details above for more info. |
Depending on the frame length configuration, 4-8 (least significant) bits from each byte in data
are transmitted. If frame length is 9, 8 bits are transmitted from each byte in data
adding one bit as specified by the CTRL register, BIT8DV field, to each byte. See USART_TxDoubleExt() for transmitting two 9 bit frames with full control of all 9 bits.
If the frame length is 10-16, 10-16 (least significant) bits from data
are transmitted.
Notice that possible parity/stop bits in asynchronous mode are not considered part of a specified frame bit length.
Note
This function will stall if the buffer is full until the buffer becomes available.
1373
of file platform/emlib/src/em_usart.c
USART_TxDoubleExt#
void USART_TxDoubleExt (USART_TypeDef * usart, uint32_t data)
Transmit two 4-9 bit frames or one 10-16 bit frame with extended control.
[in] | usart | A pointer to the USART/UART peripheral register block. |
[in] | data | Data to transmit with extended control. Contains two 16 bit words concatenated. Least significant word holds the frame transmitted first. If the frame length is 4-9, two frames with 4-9 least significant bits from each 16 bit word are transmitted. |
Notice that possible parity/stop bits in asynchronous mode are not considered part of a specified frame bit length.
Note
This function will stall if the buffer is full until the buffer becomes available.
If the frame length is 10-16 bits, 8 data bits are taken from the least significant 16 bit word and the remaining bits from the other 16 bit word.
Additional control bits are available as documented in the reference manual (set to 0 if not used). For 10-16 bit frame length, these control bits are taken from the most significant 16 bit word.
1408
of file platform/emlib/src/em_usart.c
USART_TxExt#
void USART_TxExt (USART_TypeDef * usart, uint16_t data)
Transmit one 4-9 bit frame with extended control.
[in] | usart | A pointer to the USART/UART peripheral register block. |
[in] | data | Data to transmit with extended control. Least significant bit contains frame bits. Additional control bits are available as documented in the reference manual (set to 0 if not used). |
Notice that possible parity/stop bits in asynchronous mode are not considered part of a specified frame bit length.
Note
This function will stall if the buffer is full until the buffer becomes available.
1435
of file platform/emlib/src/em_usart.c
USART_IntClear#
void USART_IntClear (USART_TypeDef * usart, uint32_t flags)
Clear one or more pending USART interrupts.
[in] | usart | Pointer to the USART/UART peripheral register block. |
[in] | flags | Pending USART/UART interrupt source(s) to clear. Use one or more valid interrupt flags for the USART module (USART_IF_nnn) OR'ed together. |
803
of file platform/emlib/inc/em_usart.h
USART_IntDisable#
void USART_IntDisable (USART_TypeDef * usart, uint32_t flags)
Disable one or more USART interrupts.
[in] | usart | Pointer to the USART/UART peripheral register block. |
[in] | flags | USART/UART interrupt source(s) to disable. Use one or more valid interrupt flags for the USART module (USART_IF_nnn) OR'ed together. |
823
of file platform/emlib/inc/em_usart.h
USART_IntEnable#
void USART_IntEnable (USART_TypeDef * usart, uint32_t flags)
Enable one or more USART interrupts.
[in] | usart | Pointer to the USART/UART peripheral register block. |
[in] | flags | USART/UART interrupt source(s) to enable. Use one or more valid interrupt flags for the USART module (USART_IF_nnn) OR'ed together. |
Note
Depending on the use, a pending interrupt may already be set prior to enabling the interrupt. To ignore a pending interrupt, consider using USART_IntClear() prior to enabling the interrupt.
844
of file platform/emlib/inc/em_usart.h
USART_IntGet#
uint32_t USART_IntGet (USART_TypeDef * usart)
Get pending USART interrupt flags.
[in] | usart | Pointer to the USART/UART peripheral register block. |
Note
The event bits are not cleared by the use of this function.
Returns
USART/UART interrupt source(s) pending. Returns one or more valid interrupt flags for the USART module (USART_IF_nnn) OR'ed together.
863
of file platform/emlib/inc/em_usart.h
USART_IntGetEnabled#
uint32_t USART_IntGetEnabled (USART_TypeDef * usart)
Get enabled and pending USART interrupt flags.
[in] | usart | Pointer to the USART/UART peripheral register block. |
Useful for handling more interrupt sources in the same interrupt handler.
Note
Interrupt flags are not cleared by the use of this function.
Returns
Pending and enabled USART interrupt sources. The return value is the bitwise AND combination of
the OR combination of enabled interrupt sources in USARTx_IEN_nnn register (USARTx_IEN_nnn) and
the OR combination of valid interrupt flags of the USART module (USARTx_IF_nnn).
887
of file platform/emlib/inc/em_usart.h
USART_IntSet#
void USART_IntSet (USART_TypeDef * usart, uint32_t flags)
Set one or more pending USART interrupts from SW.
[in] | usart | Pointer to the USART/UART peripheral register block. |
[in] | flags | USART/UART interrupt source(s) to set to pending. Use one or more valid interrupt flags for the USART module (USART_IF_nnn) OR'ed together. |
910
of file platform/emlib/inc/em_usart.h
USART_StatusGet#
uint32_t USART_StatusGet (USART_TypeDef * usart)
Get USART STATUS register.
[in] | usart | Pointer to the USART/UART peripheral register block. |
Returns
STATUS register value.
930
of file platform/emlib/inc/em_usart.h
USART_RxDataGet#
uint8_t USART_RxDataGet (USART_TypeDef * usart)
Receive one 4-8 bit frame, (or part of 10-16 bit frame).
[in] | usart | Pointer to USART/UART peripheral register block. |
This function is used to quickly receive one 4-8 bits frame by reading the RXDATA register directly, without checking the STATUS register for the RXDATAV flag. This can be useful from the RXDATAV interrupt handler, i.e., waiting is superfluous, in order to quickly read the received data. Please refer to USART_RxDataXGet() for reception of 9 bit frames.
Note
Because this function does not check whether the RXDATA register actually holds valid data, it should only be used in situations when it is certain that there is valid data, ensured by some external program routine, e.g., when handling an RXDATAV interrupt. The USART_Rx() is normally a better choice if the validity of the RXDATA register is not certain.
Notice that possible parity/stop bits in asynchronous mode are not considered part of specified frame bit length.
Returns
Data received.
969
of file platform/emlib/inc/em_usart.h
USART_RxDoubleGet#
uint16_t USART_RxDoubleGet (USART_TypeDef * usart)
Receive two 4-8 bit frames, or one 10-16 bit frame.
[in] | usart | Pointer to USART/UART peripheral register block. |
This function is used to quickly receive one 10-16 bits frame or two 4-8 bit frames by reading the RXDOUBLE register directly, without checking the STATUS register for the RXDATAV flag. This can be useful from the RXDATAV interrupt handler, i.e., waiting is superfluous, in order to quickly read the received data. This function is normally used to receive one frame when operating with frame length 10-16 bits. Please refer to USART_RxDoubleXGet() for reception of two 9 bit frames.
Note
Because this function does not check whether the RXDOUBLE register actually holds valid data, it should only be used in situations when it is certain that there is valid data, ensured by some external program routine, e.g., when handling an RXDATAV interrupt. The USART_RxDouble() is normally a better choice if the validity of the RXDOUBLE register is not certain.
Notice that possible parity/stop bits in asynchronous mode are not considered part of specified frame bit length.
Returns
Data received.
1006
of file platform/emlib/inc/em_usart.h
USART_RxDoubleXGet#
uint32_t USART_RxDoubleXGet (USART_TypeDef * usart)
Receive two 4-9 bit frames, or one 10-16 bit frame with extended information.
[in] | usart | Pointer to USART/UART peripheral register block. |
This function is used to quickly receive one 10-16 bits frame or two 4-9 bit frames by reading the RXDOUBLEX register directly, without checking the STATUS register for the RXDATAV flag. This can be useful from the RXDATAV interrupt handler, i.e., waiting is superfluous, in order to quickly read the received data.
Note
Because this function does not check whether the RXDOUBLEX register actually holds valid data, it should only be used in situations when it is certain that there is valid data, ensured by some external program routine, e.g., when handling an RXDATAV interrupt. The USART_RxDoubleExt() is normally a better choice if the validity of the RXDOUBLEX register is not certain.
Notice that possible parity/stop bits in asynchronous mode are not considered part of specified frame bit length.
Returns
Data received.
1041
of file platform/emlib/inc/em_usart.h
USART_RxDataXGet#
uint16_t USART_RxDataXGet (USART_TypeDef * usart)
Receive one 4-9 bit frame, (or part of 10-16 bit frame) with extended information.
[in] | usart | Pointer to USART/UART peripheral register block. |
This function is used to quickly receive one 4-9 bit frame, (or part of 10-16 bit frame) with extended information by reading the RXDATAX register directly, without checking the STATUS register for the RXDATAV flag. This can be useful from the RXDATAV interrupt handler, i.e., waiting is superfluous, in order to quickly read the received data.
Note
Because this function does not check whether the RXDATAX register actually holds valid data, it should only be used in situations when it is certain that there is valid data, ensured by some external program routine, e.g., when handling an RXDATAV interrupt. The USART_RxExt() is normally a better choice if the validity of the RXDATAX register is not certain.
Notice that possible parity/stop bits in asynchronous mode are not considered part of specified frame bit length.
Returns
Data received.
1075
of file platform/emlib/inc/em_usart.h
Macro Definition Documentation#
USART_INITASYNC_DEFAULT#
#define USART_INITASYNC_DEFAULTValue:
Default configuration for USART asynchronous initialization structure.
392
of file platform/emlib/inc/em_usart.h
USART_INITPRSTRIGGER_DEFAULT#
#define USART_INITPRSTRIGGER_DEFAULTValue:
Default configuration for USART PRS triggering structure.
414
of file platform/emlib/inc/em_usart.h
USART_INITSYNC_DEFAULT#
#define USART_INITSYNC_DEFAULTValue:
Default configuration for USART sync initialization structure.
520
of file platform/emlib/inc/em_usart.h
USART_INITIRDA_DEFAULT#
#define USART_INITIRDA_DEFAULTValue:
Default configuration for IrDA mode initialization structure.
640
of file platform/emlib/inc/em_usart.h
USART_INITI2S_DEFAULT#
#define USART_INITI2S_DEFAULTValue:
Default configuration for I2S mode initialization structure.
738
of file platform/emlib/inc/em_usart.h