UART (串口通信)

简介

ET6001 提供 2 组 UART 接口，定义为 UART0~1。支持 RS485 以及 2 线普通串口以及带流控的串口模式。

功能概述

支持最高波特率大于等于 1 MBaud
支持 9 位串行数据
支持起始位检测
支持中断上报
支持 FIFO TEST 模式，TX、RX FIFO 各16个
支持硬件DMA握手请求
支持配置为软件可编程RS485模式
兼容 ISO 16750 标准的自动流控制模式

软件配置流程

基本收发配置流程如下：

配置IOMUX

配置对应串口引脚为UART模式
UART软件复位

调用 UART_performSoftwareReset() 传入UARTx
配置串口

调用 UART_setConfig()
- 波特率
- 数据位
- 停止位
- 奇偶校验
使能FIFO (可选)

调用 UART_enableFIFO() 使能FIFO
使能中断 (可选)

调用 UART_enableInterrupt() 传入对应中断Mask
- UART_IT_RECV_DATA_AVAILABLE_FLAG
- UART_IT_TRANS_DATA_EMPTY_FLAG
- UART_IT_LINE_STATUS_FLAG
- UART_IT_MODEM_STATUS_FLAG
- UART_IT_PROMGRAM_THRE_FLAG
发送字符或字符数组调用 UART_writeCharArray() 或 UART_writeCharBlockingFIFO() 传入相关参数
接收字符或字符数组调用 UART_readCharArray() 或 UART_readCharBlockingFIFO() 传入相关参数

中断配置说明

UART的中断使能、中断清除、中断禁止传入的参数均为中断掩码值，具体中断掩码值定义如下：

#define UART_IT_NONE                        (0x00U)
#define UART_IT_RECV_DATA_AVAILABLE_FLAG    (0x01U)
#define UART_IT_TRANS_DATA_EMPTY_FLAG       (0x02U)
#define UART_IT_LINE_STATUS_FLAG            (0x04U)
#define UART_IT_MODEM_STATUS_FLAG           (0x08U)
#define UART_IT_PROMGRAM_THRE_FLAG          (0x80U)

UART的中断状态值与上述中断掩码值不同，具体中断状态值定义如下：

#define UART_IT_STA_MODEM_STATUS    (0x00U) //!< Modem status
#define UART_IT_STA_NO_INTERRUPT    (0x01U) //!< No interrupt pending
#define UART_IT_STA_THR             (0x02U) //!< Transmit holding register empty
#define UART_IT_STA_RECV_AVI        (0x04U) //!< Receive data available
#define UART_IT_STA_RECV_LINE       (0x06U) //!< Receive line status
#define UART_IT_STA_BUSY_DETECT     (0x07U) //!< Busy detect
#define UART_IT_STA_CHAR_TIMEOUT    (0x0CU) //!< Character timeout

编写程序时，需要注意中断掩码值和中断状态值的区别。

UART_IT_STA_THR 和 UART_IT_STA_RECV_AVI 的状态清除无需调用 UART_clearInterruptStatus() 函数。当读取IIR寄存器或者向 THR 寄存器写入数据时，UART_IT_STA_THR 和 UART_IT_STA_RECV_AVI 的状态会自动清除。

小心

UART_IT_TRANS_DATA_EMPTY_FLAG 中断和其他中断不同，只有在发送缓存寄存器或者发送FIFO中没有数据时才会触发。也就是说，发送空中断为脉冲中断。所以需要先手动发送数据才能触发该中断。另外，如果有其他更高优先级的中断到来，则该中断可能不会被触发。

Q&A

UART_IT_STA_CHAR_TIMEOUT 中断在什么情况下会触发？

当接收FIFO中有数据，但在一定时间内没有新的数据到来时，会触发 UART_IT_STA_CHAR_TIMEOUT 中断。该中断可以用来检测接收数据的结束或者接收数据的异常情况。
- 该中断生效的前提: UART_IT_RECV_DATA_AVAILABLE_FLAG 中断使能，并且使能了 FIFO 模式。
- 该中断产生的条件: 在最后 4 个字符时间内，接收FIFO 中没有数据接收或读取，并且在此期间至少有 1 个字符在FIFO中。

应用示例

UART数据收发示例：UART/UART_init_TxRx。
UART中断发送接收示例：UART/UART_IT_receive。

API Reference

Header File

src/ET6002/ET6x_Driver/Inc/et6x_uart.h

Functions

void UART_setParityMode(UART_Type *UARTx, UART_ParityType parity)

Set the parity mode of the UART port.

参数:

UARTx – The base address of the UART port.
parity – The parity mode to be set.

UART_ParityType UART_getParityMode(UART_Type *UARTx)

Get the parity mode of the UART port.

参数:: UARTx – The base address of the UART port.
返回:: The parity mode of the UART port.

void UART_setFIFOInterruptLevel(UART_Type *UARTx, UART_TxFIFOThre txLevel, UART_RxFIFOThre rxLevel)

Set the FIFO interrupt level of the UART port.

参数:

UARTx – The base address of the UART port.
txLevel – The transmit FIFO interrupt level.
rxLevel – The receive FIFO interrupt level.

void UART_getFIFOInterruptLevel(UART_Type *UARTx, UART_TxFIFOThre *txLevel, UART_RxFIFOThre *rxLevel)

Get the FIFO interrupt level of the UART port.

参数:

UARTx – The base address of the UART port.
txLevel – The transmit FIFO interrupt level.
rxLevel – The receive FIFO interrupt level.

void UART_getConfig(UART_Type *UARTx, uint32_t *lspclkHz, uint32_t *baud, uint32_t *config)

Get the configuration information of the UART port.

参数:

UARTx – The base address of the UART port.
lspclkHz – The frequency of the UART clock.
baud – The baud rate of the UART port.
config – The configuration information of the UART port.

void UART_enableFIFO(UART_Type *UARTx)

Enable the FIFO of the UART port.

参数:: UARTx – The base address of the UART port.

void UART_disableFIFO(UART_Type *UARTx)

Disable the FIFO of the UART port.

参数:: UARTx – The base address of the UART port.

bool UART_isFIFOEnabled(UART_Type *UARTx)

Check if the FIFO is enabled for the given UART peripheral.

参数:: UARTx – Pointer to the UART peripheral instance.
返回:: true if FIFO is enabled, false otherwise.

void UART_resetRxFIFO(UART_Type *UARTx)

Reset the receive FIFO for the given UART peripheral.

参数:: UARTx – Pointer to the UART peripheral instance.

void UART_resetTxFIFO(UART_Type *UARTx)

Reset the transmit FIFO for the given UART peripheral.

参数:: UARTx – Pointer to the UART peripheral instance.

void UART_resetChannels(UART_Type *UARTx)

Reset both the receive and transmit FIFOs for the given UART peripheral.

参数:: UARTx – Pointer to the UART peripheral instance.

bool UART_isDataAvailableNonFIFO(UART_Type *UARTx)

Check if data is available in the receive buffer for non-FIFO mode.

参数:: UARTx – Pointer to the UART peripheral instance.
返回:: true if data is available, false otherwise.

bool UART_isSpaceAvailableNonFIFO(UART_Type *UARTx)

Check if space is available in the transmit buffer for non-FIFO mode.

参数:: UARTx – Pointer to the UART peripheral instance.
返回:: true if space is available, false otherwise.

UART_TxFIFOLevel UART_getTxFIFOStatus(UART_Type *UARTx)

Get the status of the transmit FIFO for the given UART peripheral.

参数:: UARTx – Pointer to the UART peripheral instance.
返回:: The transmit FIFO level.

UART_RxFIFOLevel UART_getRxFIFOStatus(UART_Type *UARTx)

Get the status of the receive FIFO for the given UART peripheral.

参数:: UARTx – Pointer to the UART peripheral instance.
返回:: The receive FIFO level.

bool UART_isTransmitterBusy(UART_Type *UARTx)

Check if the transmitter is busy for the given UART peripheral.

参数:: UARTx – Pointer to the UART peripheral instance.
返回:: true if the transmitter is busy, false otherwise.

void UART_writeCharBlockingFIFO(UART_Type *UARTx, uint8_t data)

Write a character to the transmit buffer in blocking mode with FIFO enabled.

参数:

UARTx – Pointer to the UART peripheral instance.
data – The character to be written.

void UART_writeCharBlockingNonFIFO(UART_Type *UARTx, uint8_t data)

Write a character to the transmit buffer in blocking mode without FIFO.

参数:

UARTx – Pointer to the UART peripheral instance.
data – The character to be written.

void UART_writeCharNonBlocking(UART_Type *UARTx, uint8_t data)

Write a character to the transmit buffer in non-blocking mode.

参数:

UARTx – Pointer to the UART peripheral instance.
data – The character to be written.

uint16_t UART_getRxStatus(UART_Type *UARTx)

Get the receive status for the given UART peripheral.

参数:: UARTx – Pointer to the UART peripheral instance.
返回:: The receive status.

uint16_t UART_getModemStatus(UART_Type *UARTx)

Get the modem status of the UART.

This function retrieves the modem status of the specified UART peripheral.

参数:: UARTx – Pointer to the UART_Type structure, which contains the registers of the UART module.
返回:: The modem status as a 16-bit value, which includes various flags indicating the state of the modem.

uint8_t UART_readCharBlockingFIFO(UART_Type *UARTx)

Read a character from the receive buffer in blocking mode with FIFO enabled.

参数:: UARTx – Pointer to the UART peripheral instance.
返回:: The character read from the buffer.

uint8_t UART_readCharBlockingNonFIFO(UART_Type *UARTx)

Read a character from the receive buffer in blocking mode without FIFO.

参数:: UARTx – Pointer to the UART peripheral instance.
返回:: The character read from the buffer.

uint8_t UART_readCharNonBlocking(UART_Type *UARTx)

Reads a character from the UART receive buffer in non-blocking mode.

参数:: UARTx – The UART peripheral instance.
返回:: The character read from the receive buffer.

void UART_performSoftwareReset(UART_Type *UARTx)

Performs a software reset of the UART peripheral.

参数:: UARTx – The UART peripheral instance.

void UART_enableLoopback(UART_Type *UARTx)

Enables the loopback mode of the UART peripheral.

参数:: UARTx – The UART peripheral instance.

void UART_disableLoopback(UART_Type *UARTx)

Disables the loopback mode of the UART peripheral.

参数:: UARTx – The UART peripheral instance.

void UART_setConfig(UART_Type *UARTx, uint32_t baud, uint32_t config)

Set the UART configuration.

This function configures the UART with the specified baud rate and other settings.

参数:

UARTx – Pointer to the UART peripheral instance.
baud – The desired baud rate.
config – The configuration bits for the UART line control register.

void UART_writeCharArray(UART_Type *UARTx, const uint8_t *const array, uint16_t length)

Write an array of characters to the UART.

This function writes a specified number of characters from an array to the UART.

参数:

UARTx – Pointer to the UART peripheral instance.
array – Pointer to the array of characters to be written.
length – The number of characters to write.

void UART_readCharArray(UART_Type *UARTx, uint8_t *const array, uint16_t length)

Read an array of characters from the UART.

This function reads a specified number of characters from the UART into an array.

参数:

UARTx – Pointer to the UART peripheral instance.
array – Pointer to the array where the received characters will be stored.
length – The number of characters to read.

void UART_enableInterrupt(UART_Type *UARTx, uint32_t intFlags)

Enable UART interrupts.

This function enables the specified UART interrupts.

参数:

UARTx – Pointer to the UART peripheral instance.
intFlags – The interrupt flags to be enabled, ref to UART_IT_xxxx

void UART_disableInterrupt(UART_Type *UARTx, uint32_t intFlags)

Disable UART interrupts.

This function disables the specified UART interrupts.

参数:

UARTx – Pointer to the UART peripheral instance.
intFlags – The interrupt flags to be disabled, ref to UART_IT_xxxx

uint32_t UART_getInterruptStatus(UART_Type *UARTx)

Get the interrupt status of the UART.

参数:: UARTx – Pointer to the UART_Type structure
返回:: Interrupt status ref to !! UART_IT_STA_xxxx

void UART_clearInterruptStatus(UART_Type *UARTx, uint32_t intFlags)

Clears the interrupt status of the UART.

This function clears the interrupt status of the UART based on the provided interrupt flags.

参数:

UARTx – Pointer to the UART_Type structure, which contains the registers of the UART module.
intFlags – Interrupt flags to be cleared. Can be a combination of the following:
- UART_IT_TRANS_DATA_EMPTY_FLAG: Clear the transmit data empty interrupt flag.
- UART_IT_MODEM_STATUS_FLAG: Clear the modem status interrupt flag.
- UART_IT_LINE_STATUS_FLAG: Clear the line status interrupt flag.

void UART_setBaud(UART_Type *UARTx, uint32_t baud)

Sets the baud rate of the UART.

This function sets the baud rate of the UART based on the provided clock frequency and baud rate.

参数:

UARTx – Pointer to the UART_Type structure, which contains the registers of the UART module.
baud – The desired baud rate.

Macros

UART_IT_NONE: interrupt flags

UART_IT_RECV_DATA_AVAILABLE_FLAG

UART_IT_TRANS_DATA_EMPTY_FLAG

UART_IT_LINE_STATUS_FLAG

UART_IT_MODEM_STATUS_FLAG

UART_IT_PROMGRAM_THRE_FLAG

UART_IT_STA_MODEM_STATUS

Interrupt status flags.

Modem status

UART_IT_STA_NO_INTERRUPT: No interrupt pending.

UART_IT_STA_THR: Transmit holding register empty.

UART_IT_STA_RECV_AVI: Receive data available.

UART_IT_STA_RECV_LINE: Receive line status.

UART_IT_STA_BUSY_DETECT: Busy detect.

UART_IT_STA_CHAR_TIMEOUT: Character timeout.

UART_CONFIG_WLEN_8

uart config word length

8 bit data

UART_CONFIG_WLEN_7: 7 bit data

UART_CONFIG_WLEN_6: 6 bit data

UART_CONFIG_WLEN_5: 5 bit data

UART_CONFIG_STOP_ONE

UART config stop bits.

One stop bit

UART_CONFIG_STOP_TWO: Two stop bits.

UART_CONFIG_PAR_MASK: Parity Mask.

UART_RXSTATUS_PARITY

UART RX Status.

Parity error

UART_RXSTATUS_OVERRUN: Overrun error.

UART_RXSTATUS_FRAMING: Framing error.

UART_RXSTATUS_BREAK: Break detect.

UART_RXSTATUS_READY: Receiver ready.

UART_RXSTATUS_ERROR: Receiver error.

UART_MODEM_STA_DCTS

UART Modem Status.

Delta CTS

UART_MODEM_STA_DDSR: Delta DSR.

UART_MODEM_STA_TERI: Trailing Edge Ring Indicator.

UART_MODEM_STA_DDCD: Delta DCD.

UART_MODEM_STA_CTS: Clear To Send.

UART_MODEM_STA_DSR: Data Set Ready.

UART_MODEM_STA_RI: Ring Indicator.

UART_MODEM_STA_DCD: Data Carrier Detect.

Enumerations

enum UART_ParityType

UART config parity.

Values:

enumerator UART_CONFIG_PAR_NONE: No parity.

enumerator UART_CONFIG_PAR_EVEN: Even parity.

enumerator UART_CONFIG_PAR_ODD: Odd parity.

enum UART_TxFIFOThre

UART config TxFIFO Thre.

Values:

enumerator UART_TX_FIFO_EMPTY

enumerator UART_TX_FIFO_CHAR_2

enumerator UART_TX_FIFO_QUARTER_FULL

enumerator UART_TX_FIFO_HALF_FULL

enum UART_RxFIFOThre

UART config RxFIFO Thre.

Values:

enumerator UART_RX_FIFO_CHAR_1

enumerator UART_RX_FIFO_QUARTER_FULL

enumerator UART_RX_FIFO_HALF_FULL

enumerator UART_RX_FIFO_FULL_2

enum UART_TxFIFOLevel

UART TX FIFO Level.

Values:

enumerator UART_FIFO_TX0: Transmit interrupt empty.

enumerator UART_FIFO_TX1: Transmit interrupt 1/16 full.

enumerator UART_FIFO_TX2: Transmit interrupt 2/16 full.

enumerator UART_FIFO_TX3: Transmit interrupt 3/16 full.

enumerator UART_FIFO_TX4: Transmit interrupt 4/16 full.

enumerator UART_FIFO_TX5: Transmit interrupt 5/16 full.

enumerator UART_FIFO_TX6: Transmit interrupt 6/16 full.

enumerator UART_FIFO_TX7: Transmit interrupt 7/16 full.

enumerator UART_FIFO_TX8: Transmit interrupt 8/16 full.

enumerator UART_FIFO_TX9: Transmit interrupt 9/16 full.

enumerator UART_FIFO_TX10: Transmit interrupt 10/16 full.

enumerator UART_FIFO_TX11: Transmit interrupt 11/16 full.

enumerator UART_FIFO_TX12: Transmit interrupt 12/16 full.

enumerator UART_FIFO_TX13: Transmit interrupt 13/16 full.

enumerator UART_FIFO_TX14: Transmit interrupt 14/16 full.

enumerator UART_FIFO_TX15: Transmit interrupt 15/16 full.

enumerator UART_FIFO_TX16: Transmit interrupt full.

enum UART_RxFIFOLevel

UART RX FIFO Level.

Values:

enumerator UART_FIFO_RX0: Receive interrupt empty.

enumerator UART_FIFO_RX1: Receive interrupt 1/16 full.

enumerator UART_FIFO_RX2: Receive interrupt 2/16 full.

enumerator UART_FIFO_RX3: Receive interrupt 3/16 full.

enumerator UART_FIFO_RX4: Receive interrupt 4/16 full.

enumerator UART_FIFO_RX5: Receive interrupt 5/16 full.

enumerator UART_FIFO_RX6: Receive interrupt 6/16 full.

enumerator UART_FIFO_RX7: Receive interrupt 7/16 full.

enumerator UART_FIFO_RX8: Receive interrupt 8/16 full.

enumerator UART_FIFO_RX9: Receive interrupt 9/16 full.

enumerator UART_FIFO_RX10: Receive interrupt 10/16 full.

enumerator UART_FIFO_RX11: Receive interrupt 11/16 full.

enumerator UART_FIFO_RX12: Receive interrupt 12/16 full.

enumerator UART_FIFO_RX13: Receive interrupt 13/16 full.

enumerator UART_FIFO_RX14: Receive interrupt 14/16 full.

enumerator UART_FIFO_RX15: Receive interrupt 15/16 full.

enumerator UART_FIFO_RX16: Receive interrupt full.