UART Usage Guide

The S100 MCU chip has a total of 3 UART interfaces, namely UART4 to UART6. Among them, UART4 is used as the debug console (shared by MCU0 and MCU1), with DMA disabled by default. The default configuration is as follows:

Configuration Item	UART4	UART5	UART6
Channel Identifier	Uart_Channel0	Uart_Channel1	Uart_Channel2
Baud Rate	921600	921600	921600
Parity Bit	None	None	None
Stop Bits	1 bit	1 bit	1 bit
Data Bits	8 bits	8 bits	8 bits

Hardware Support

Maximum number of UARTs available on the MCU: 3
UART FIFO depth: 8 bytes × 16
Supports common baud rates such as 4800, 9600, 38400, 115200, and 921600
Supports data bit configuration from 5 to 8 bits
Supports parity configuration (odd/even/none)
Supports stop bit configuration of 1, 1.5, or 2 bits
Supports DMA mode; in DMA mode, the transmit and receive buffer addresses provided by the application layer must be 64-byte aligned

Software Architecture

UART APP: Application-layer code for UART.
UART Interface: Interface-layer code providing standardized UART operation APIs.
UART LLD: Low-level driver code that directly manipulates hardware registers to implement core functionalities such as asynchronous/synchronous transmission, interrupt handling, and FIFO management.
UART PBcfg: Peripheral configuration (PB) files containing UART peripheral configuration parameters.
Hardware: UART hardware.

MCU Software Architecture Diagram

Code Paths

McalCdd/Common/Register/inc/Uart_Register.h # Register-related definitions
McalCdd/Uart/src/Uart.c # Driver implementation
McalCdd/Uart/src/Uart_Lld.c # Low-level driver implementation
McalCdd/Uart/inc/Uart.h # Driver header file
McalCdd/Uart/inc/Uart_Lld.h # Low-level driver header file
Config/McalCdd/gen_s100_sip_B_mcu1/Uart/src/Uart_PBcfg.c # MCU PB configuration file
Config/McalCdd/gen_s100_sip_B_mcu1/Uart/inc/Uart_PBcfg.h # PB configuration header file
samples/Uart/Uart_sample/Uart_Test.c # Sample test code

Application Sample

Usage Example

On the S100 development board, UART5 is exposed for user development and learning purposes. The corresponding pins are located on the MCU Expansion Header of the Main Board.

//TODO Add board image

In the mainline code, UART5 is by default passed through to Acore. Therefore, before testing, you need to enter the following command in the MCU console to release UART5:

D-Robotics:/$ ipcbox_set_mode uart 0
[058.203488 0]uart processing disabled
[058.203749 0]uart2ipc_release
Return: 0, 0x00000000

uarttest 1: Loopback test (note: connect the RX pin to the TX pin)

D-Robotics:/$ uarttest 1
[073.515926 0]Async receive ret: 0
Tx: 0 1 2 3 4 5 6 7 8 9 a b c d e f 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38                                                                                                                                 39 3a 3b 3c 3d 3e 3f 41 42 43 44 45
Rx: 0 1 2 3 4 5 6 7 8 9 a b c d e f 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38                                                                                                                                 39 3a 3b 3c 3d 3e 3f 41 42 43 44 45
[073.523782 0]SyncSend & AsyncReceive test pass!

uarttest 2: Receive data
A serial assistant (configured at 921600 baud, 8-N-1) is used to send data to the MCU.

D-Robotics:/$ uarttest 2
Rx: 0 1 2 3 4 5 6 7 8 9 a b c d e f 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 41 42 43 44 45
[0359.598869 0]AsyncSend & ASyncReceive test pass!

uarttest 3: Transmit data

D-Robotics:/$ uarttest 3
Tx: 0 1 2 3 4 5 6 7 8 9 a b c d e f 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 41 42 43 44 45

uarttest 4: Retrieve GPS data (internal RDK test case).
uarttest 5: Set baud rate to 9600

D-Robotics:/$ uarttest 5
[042602.833314 0]Channel 1 Baud: 9600

uarttest 6: Set baud rate to 115200

D-Robotics:/$ uarttest 6
[042617.473286 0]Channel 1 Baud: 115200

Application Programming Interface (API)

void Uart_Init(void)

Description: Subsystem driver initialization function.

Parameters (in)
    None
Parameters (inout)
    None
Parameters (out)
    None
Return value: None

void Uart_Deinit(void)

Description: Subsystem driver deinitialization function.

Parameters (in)
    None
Parameters (inout)
    None
Parameters (out)
    None
Return value: None

Std_ReturnType Uart_BaudSet(uint8 Channel, Uart_BaudrateType Baudrate)

Description: Set the baud rate for a UART channel.

Parameters (in)
    Channel: UART channel
    Baudrate: Desired baud rate
Parameters (inout)
    None
Parameters (out)
    None
Return value: Std_ReturnType
    E_OK: Set successfully
    E_NOT_OK: Set failed

Std_ReturnType Uart_BaudGet(uint8 Channel, uint32* Baudrate)

Description: Get the current baud rate of a UART channel.

Parameters (in)
    Channel: UART channel
Parameters (inout)
    None
Parameters (out)
    Baudrate: Current baud rate
Return value: Std_ReturnType
    E_OK: Get successfully
    E_NOT_OK: Get failed

Std_ReturnType Uart_SetDatabits(uint8 Channel, uint8 Databits)

Description: Set the number of data bits for a UART channel.

Parameters (in)
    Channel: UART channel
    Databits: Desired number of data bits
Parameters (inout)
    None
Parameters (out)
    None
Return value: Std_ReturnType
    E_OK: Set successfully
    E_NOT_OK: Set failed

Std_ReturnType Uart_SetStopbit(uint8 Channel, uint8 Stopbit)

Description: Set the number of stop bits for a UART channel.

Parameters (in)
    Channel: Uart Channel
    Stopbit: Desired Stopbit
Parameters(inout)
    None
Parameters(out)
    None
Return value: Std_ReturnType
	E_OK: set success
    E_NOT_OK: set failed

Std_ReturnType Uart_SetParity(uint8 Channel, Uart_ParityType CurParity)

Description: Set Parity type for an Uart channel.

Parameters(in)
    Channel: Uart Channel
    CurParity: Desired Parity
Parameters(inout)
    None
Parameters(out)
    None
Return value: Std_ReturnType
	E_OK: set success
    E_NOT_OK: set failed

Uart_StatusType Uart_StatusGet(uint8 Channel, uint32* BytesTransfered, Uart_DataDirectionType TransferType)

Description: Gets the status of an Uart channel.

Sync/Async: Synchronous
Parameters(in)
    Channel: Uart Channel
    BytesTransfered: Byte has transfered
    TransferType: Send or Receive
Parameters(inout)
    None
Parameters(out)
    None
Return value: Uart_StatusType
    Uart current state

Std_ReturnType Uart_SyncDataTrans(uint8 Channel, const uint8* Buffer, uint32 BufferSize, uint32 Timeout)

Description: Sends an Uart message blocking.

Sync/Async: Synchronous
Parameters(in)
    Channel: Uart Channel
    Buffer: pointer to Data buffer
    BufferSize: number bytes buffer
    Timeout: Timeout value
Parameters(inout)
    None
Parameters(out)
    None
Return value: Std_ReturnType
    E_OK: command has been accepted
    E_NOT_OK: command has not been accepted

Std_ReturnType Uart_SyncDataReceive(uint8 Channel, const uint8* Buffer, uint32 BufferSize, uint32 Timeout)

Description: Receive an Uart message blocking.

Sync/Async: Synchronous
Parameters(in)
    Channel: Uart Channel
    Buffer: pointer to Data buffer
    BufferSize: number bytes buffer
    Timeout: Timeout value
Parameters(inout)
    None
Parameters(out)
    None
Return value: Std_ReturnType
    E_OK: command has been accepted
    E_NOT_OK: command has not been accepted

Std_ReturnType Uart_AsyncDataTrans(uint8 Channel, const uint8* Buffer, uint32 BufferSize)

Description: Sends an Uart message async.

Sync/Async: Asynchronous
Parameters(in)
    Channel: Uart Channel
    Buffer: pointer to Data buffer
    BufferSize: number bytes buffer
Parameters(inout)
    None
Parameters(out)
    None
Return value: Std_ReturnType
    E_OK: command has been accepted
    E_NOT_OK: command has not been accepted

Std_ReturnType Uart_AsyncDataReceive(uint8 Channel, const uint8* Buffer, uint32 BufferSize)

Description: Receive an Uart message async.

Sync/Async: Asynchronous
Parameters(in)
    Channel: Uart Channel
    Buffer: pointer to Data buffer
    BufferSize: number bytes buffer
Parameters(inout)
    None
Parameters(out)
    None
Return value: Std_ReturnType
    E_OK: command has been accepted
    E_NOT_OK: command has not been accepted

void Uart_GetVersionInfo(Std_VersionInfoType* VersionInfo)

Description: This function Gets the version information of this module

Sync/Async: Synchronous
Parameters(in)
    None
Parameters(inout)
    None
Parameters(out)
    VersionInfo: version information of this module
Return value: None

Hardware Support​

Software Architecture​

Code Paths​

Application Sample​

Usage Example​

Application Programming Interface (API)​

void Uart_Init(void)​

void Uart_Deinit(void)​

Std_ReturnType Uart_BaudSet(uint8 Channel, Uart_BaudrateType Baudrate)​

Std_ReturnType Uart_BaudGet(uint8 Channel, uint32* Baudrate)​

Std_ReturnType Uart_SetDatabits(uint8 Channel, uint8 Databits)​

Std_ReturnType Uart_SetStopbit(uint8 Channel, uint8 Stopbit)​

Std_ReturnType Uart_SetParity(uint8 Channel, Uart_ParityType CurParity)​

Uart_StatusType Uart_StatusGet(uint8 Channel, uint32* BytesTransfered, Uart_DataDirectionType TransferType)​

Std_ReturnType Uart_SyncDataTrans(uint8 Channel, const uint8* Buffer, uint32 BufferSize, uint32 Timeout)​

Std_ReturnType Uart_SyncDataReceive(uint8 Channel, const uint8* Buffer, uint32 BufferSize, uint32 Timeout)​

Std_ReturnType Uart_AsyncDataTrans(uint8 Channel, const uint8* Buffer, uint32 BufferSize)​

Std_ReturnType Uart_AsyncDataReceive(uint8 Channel, const uint8* Buffer, uint32 BufferSize)​

void Uart_GetVersionInfo(Std_VersionInfoType* VersionInfo)​