
1. Function description

   This test example demonstrates the basic communication between LPUART and USARTz via DMA (interrupt).
    USARTz can be USART2.
     First, DMA transfers the TxBuffer1 data to the LPUART send data register. After the transfer is completed, 
    a DMA interrupt is generated, and then the data is sent to USARTz. USARTz receives data, DMA moves data 
    from USARTz receive data register to RxBuffer2, and generates DMA interrupt after completion.
     At the same time, DMA transfers TxBuffer2 data to the USARTz send data register, the transfer is completed 
    and a DMA interrupt is generated, and then the data is sent to LPUART. LPUART receives data, DMA moves data 
    from LPUART receive data register to RxBuffer1, and generates DMA interrupt after completion.
     Finally, compare the two groups of receiving and sending data respectively, and store the comparison results 
    in the TransferStatus1 variable and the TransferStatus2 variable.


2. Use environment
    Software development environment: KEIL MDK-ARM V5.30.0.0
    Hardware environment: Developed based on the development board N32WB031_STB


3. Instructions for use

    The system clock configuration is as follows:
    -Clock source = HSI 64M
    -System clock = 64MHz
    
    The LPUART configuration is as follows:
    -Baud rate = 115200 baud
    -Word length = 8 data bits (fixed)
    -1 stop bit (fixed)
    -Verification control disabled
    -Hardware flow control disabled (RTS and CTS signals)
    -Receiver and transmitter enable
    -DMA transmit mode and DMA receive mode enable
    
    The USART2 configuration is as follows:
    -Baud rate = 115200 baud
    -Word length = 8 data bits 
    -1 stop bit 
    -Verification control disabled
    -Hardware flow control disabled (RTS and CTS signals)
    -Receiver and transmitter enable
    -DMA transmit mode and DMA receive mode enable
    
    The USART pin connections are as follows:
    -LPUART_Tx.PB1 <-------> USART2_Rx.PB5
    -LPUART_Rx.PB2 <-------> USART2_Tx.PB4

    Log print: 
    - DEMO board PB6(TX), baud rate: 115200, 8 data bits, 1 stop bit, no parity bit, no hardware flow control

    
    Test steps and phenomena:
    -After the Demo is compiled in the KEIL environment, download it to the MCU
    -Reset operation, check the variables TransferStatus1 and TransferStatus2 in turn, 
      PASSED means the test passed, FAILED means the test is abnormal


4. Matters needing attention
 