Overview
========
The spi_HS_LSPI_dma_b2b_transfer_slave example shows how to use driver API to transfer in DMA way.  

In this example, one spi instance as master and another spi instance on the other board as slave. 
Master sends a piece of data to slave, and receive a piece of data from slave. This example checks
if the data received from master is correct. This example needs to work with  spi_HS_LSPI_dma_b2b_transfer_slave example.

Note: This example will run in slave mode, please prepare another board for master, and the slave 
​      board should be started first.

Project Infomation

Program Flow:
Main routine:
  1.Initialize the hardware.
​	Configure pin settings, clock settings by using BOARD_InitHardware();
​	
  2.Send information to terminal by using debug console.
​	
  3.Initialize the SPI with configuration.
​	
  4.Set up DMA configuration for slave SPI.
​    Initialize DMA and DMA channel setting(create handle and set callback) for both
​    SPI RX and TX, set prioritory for TX channel and RX channel.
​	
  5.Start SPI master transfer in DMA way.
​    Initialize buffers and start SPI transfer in DMA way.
​	
  6.Check if data from master is all right.
​    Waiting for transmission complete, print received data and log information to terminal.

  7.De-initialize the SPI and DMA.

Toolchain supported
===================
- IAR embedded Workbench  9.20.1
- Keil MDK  5.34
- GCC ARM Embedded  10.2.1
- MCUXpresso  11.4.1

Hardware requirements
=====================
- Micro USB cable
- Two LPCXpresso55S36 boards
- Personal Computer

Board settings
==============
Connect SPI master on board to SPI slave on other board
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Master_board(SPI8)           Slave_board(SPI8)                          
Pin Name   Board Location     Pin Name   Board Location                     
MISO       J7    pin 5        MISO       J7    pin 5 
MOSI       J7    pin 6        MOSI       J7    pin 6
SCK        J7    pin 4        SCK        J7    pin 4
SSEL0      J7    pin 3        SSEL0      J7    pin 3
GND        J7    pin 8        GND        J7    pin 8
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Remove jumper JP48.
    
Prepare the Demo
================
1.  Connect a micro USB cable between the PC host and the CMSIS DAP USB port (J1) on the board
2.  Open a serial terminal with the following settings (See Appendix A in Getting started guide for description how to determine serial port number):
    - 115200 baud rate
    - 8 data bits
    - No parity
    - One stop bit
    - No flow control
3.  Download the program to the target board.
4.  Reset the SoC and run the project.

Running the demo
================
When the demo runs successfully, the log would be seen on the CMSIS DAP terminal like:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is SPI DMA tranfer slave example. 
This example will communicate with another master SPI on the other board. 
Slave board is working...!
The received data are: 
    0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08 0x09 0x0A 0x0B 0x0C 0x0D 0x0E 0x0F 
    0x10 0x11 0x12 0x13 0x14 0x15 0x16 0x17 0x18 0x19 0x1A 0x1B 0x1C 0x1D 0x1E 0x1F 
    0x20 0x21 0x22 0x23 0x24 0x25 0x26 0x27 0x28 0x29 0x2A 0x2B 0x2C 0x2D 0x2E 0x2F 
    0x30 0x31 0x32 0x33 0x34 0x35 0x36 0x37 0x38 0x39 0x3A 0x3B 0x3C 0x3D 0x3E 0x3F 
SPI transfer all data matched!

​~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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