USART - Synchronous/Asynchronous Serial
Description
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:
To initialize the USART for asynchronous operation (e.g., UART):
To initialize the USART for synchronous operation (e.g., SPI):
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
- UART hardware flow control is not directly supported in hardware on _SILICON_LABS_32B_SERIES_0 parts.
- UARTDRV supports all types of UART flow control. Software assisted hardware flow control is available for parts without true UART hardware flow control.
Data Structures |
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struct | USART_InitAsync_TypeDef |
Asynchronous mode initialization structure.
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struct | USART_PrsTriggerInit_TypeDef |
USART PRS trigger enable.
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struct | USART_InitSync_TypeDef |
Synchronous mode initialization structure.
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struct | USART_InitIrDA_TypeDef |
IrDA mode initialization structure.
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struct | USART_InitI2s_TypeDef |
I2S mode initialization structure.
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Functions |
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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).
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uint32_t | USART_BaudrateCalc (uint32_t refFreq, uint32_t clkdiv, bool syncmode, USART_OVS_TypeDef ovs) |