SPI Master High Speed

This sample demonstrates how SPI0 sends and receives data in high-speed mode. In this example, SPI is configured as a master and the direction is full-duplex. The SPI clock is set to 40MHz, and it is recommended to use DMA mode and dedicated pins for high speed. The chip writes some data to SPI slave and then chip reads data from SPI slave.

Requirements

For hardware requirements, please refer to the Requirements.

Wiring

Connect P1_2 (master CS) to CS of SPI slave device, connect P1_3 (master SCK) to SCK of SPI slave device, connect P1_4 (master MOSI) to MOSI of SPI slave device, and connect P1_5 (master MISO) to MISO of SPI slave device.

The hardware connection of SPI sample code is shown in the figure below.

SPI Sample Code Hardware Connection Diagram

Configurations

1. The following macros can be configured to modify pin definitions.

   • #define SPI0_HS_CS P1_2

   • #define SPI0_HS_SCK P1_3

   • #define SPI0_HS_MOSI P1_4

   • #define SPI0_HS_MISO P1_5

2. The entry function is as follows, call this function in main() to run this sample code. For more details, please refer to the Initialization.

   spi0_hs_dma_demo();
   

Building and Downloading

For building and downloading, please refer to the Building and Downloading.

Experimental Verification

1. Press the Reset button on the EVB, the data in the array sendbuf is sent to SPI slave device.

2. When completing the transmission, it enters the GDMA interrupt and prints log.

   spi_tx_dma_handler
   

3. After the slave device receives the data, the slave device sends data to the chip. The chip stores the received data in array readbuf and prints the received data in Debug Analyzer.

   spi_rx_dma_handler: readbuf[0] 0x%x
   ...
   spi_rx_dma_handler: readbuf[1023] 0x%x
   

Code Overview

Source Code Directory

• For project directory, please refer to Source Code Directory.

• Source code directory: sdk\src\sample\io_demo\spi\spi0_hs\spi0_hs_dma_demo.c .

SPI Initialization Flow

The initialization flow for peripherals can refer to Initialization Flow.

SPI initialization flow is shown in the following figure.

SPI Initialization Flow Chart

1. Call Pad_Config() and Pinmux_Config() to initialize the pin.

   static void board_spi_init(void)
   {
      /* SPI0 */
      Pinmux_Config(SPI0_HS_SCK, SPI0_CLK_MASTER);
      Pinmux_Config(SPI0_HS_MOSI, SPI0_MO_MASTER);
      Pinmux_Config(SPI0_HS_MISO, SPI0_MI_MASTER);
      Pinmux_Config(SPI0_HS_CS, SPI0_SS_N_0_MASTER);
   
      Pad_Config(SPI0_HS_SCK, PAD_PINMUX_MODE, PAD_IS_PWRON, PAD_PULL_NONE, PAD_OUT_DISABLE, PAD_OUT_LOW);
      Pad_Config(SPI0_HS_MOSI, PAD_PINMUX_MODE, PAD_IS_PWRON, PAD_PULL_NONE, PAD_OUT_DISABLE,
                  PAD_OUT_LOW);
      Pad_Config(SPI0_HS_MISO, PAD_PINMUX_MODE, PAD_IS_PWRON, PAD_PULL_NONE, PAD_OUT_DISABLE,
                  PAD_OUT_LOW);
      Pad_Config(SPI0_HS_CS, PAD_PINMUX_MODE, PAD_IS_PWRON, PAD_PULL_NONE, PAD_OUT_DISABLE, PAD_OUT_LOW);
   }
   

2. Call pm_cpu_freq_set() to set CPU frequency to 120MHz.

3. Call pll4_enable_cko1 to enable PLL4 clock, and call RCC_SPIClkSourceSwitch() to switch PLL4 as SPI0 clock source.

4. Call RCC_PeriphClockCmd() to enable the SPI clock and function.

5. Initialize the SPI peripheral:

   1. Define the SPI_InitTypeDef type SPI_InitStructure, and call SPI_StructInit() to pre-fill SPI_InitStructure with default values.

   2. Modify the SPI_InitStructure parameters as needed. The SPI initialization parameter configuration is shown in the table below.

   3. Call SPI_Init() to initialize the SPI peripheral, SPI0_HS is seleted.

   SPI Initialization Parameters

   SPI Hardware Parameters	Setting in the SPI_InitStructure	SPI
   Direction	SPI_InitTypeDef::SPI_Direction	SPI_Direction_FullDuplex
   Device Role (SPI Master or SPI Slave)	SPI_InitTypeDef::SPI_Mode	SPI_Mode_Master
   Data Frame Size	SPI_InitTypeDef::SPI_DataSize	SPI_DataSize_8b
   Clock Polarity	SPI_InitTypeDef::SPI_CPOL	SPI_CPOL_High
   Clock Phase	SPI_InitTypeDef::SPI_CPHA	SPI_CPHA_1Edge
   Clock Div	SPI_InitTypeDef::SPI_BaudRatePrescaler	4
   Receive FIFO Threshold Level	SPI_InitTypeDef::SPI_RxThresholdLevel	0
   Frame Format	SPI_InitTypeDef::SPI_FrameFormat	SPI_Frame_Motorola
   RX Sample Delay	SPI_InitTypeDef::SPI_RxSampleDly	1
   TX Water Level	SPI_InitTypeDef::SPI_RxWaterlevel	25
   RX Water Level	SPI_InitTypeDef::SPI_TxWaterlevel	31

6. Call SPI_Cmd() to enable SPI, SPI0_HS is seleted.

TX DMA Initialization Flow

The initialization flow for peripherals can refer to Initialization Flow.

SPI TX DMA initialization flow is shown in the following figure.

SPI TX DMA Initialization Flow Chart

1. Call RCC_PeriphClockCmd() to enable the GDMA clock and function.

2. Initialize the GDMA peripheral:

   1. Define the GDMA_InitTypeDef type GDMA_InitStruct, and call GDMA_StructInit() to pre-fill GDMA_InitStruct with default values.

   2. Modify the GDMA_InitStruct parameters as needed. The GDMA initialization parameter configuration is shown in the table below.

   3. Call GDMA_Init() to initialize the GDMA peripheral.

   GDMA Initialization Parameters

   GDMA Hardware Parameters	Setting in the GDMA_InitStruct	GDMA
   Channel Num	GDMA_InitTypeDef::GDMA_ChannelNum	SPI_TX_DMA_CHANNEL_NUM
   Transfer Direction	GDMA_InitTypeDef::GDMA_DIR	GDMA_DIR_MemoryToPeripheral
   Buffer Size	GDMA_InitTypeDef::GDMA_BufferSize	DMA_BUFFER_SIZE
   Source Address Increment or Decrement	GDMA_InitTypeDef::GDMA_SourceInc	DMA_SourceInc_Inc
   Destination Address Increment or Decrement	GDMA_InitTypeDef::GDMA_DestinationInc	DMA_DestinationInc_Fix
   Source Data Size	GDMA_InitTypeDef::GDMA_SourceDataSize	GDMA_DataSize_Byte
   Destination Data Size	GDMA_InitTypeDef::GDMA_DestinationDataSize	GDMA_DataSize_Byte
   Source Burst Transaction Length	GDMA_InitTypeDef::GDMA_SourceMsize	GDMA_Msize_32
   Destination Burst Transaction Length	GDMA_InitTypeDef::GDMA_DestinationMsize	GDMA_Msize_32
   Source Address	GDMA_InitTypeDef::GDMA_SourceAddr	sendbuf
   Destination Address	GDMA_InitTypeDef::GDMA_DestinationAddr	SPI0_HS->DR
   Destination Handshake	GDMA_InitTypeDef::GDMA_DestHandshake	GDMA_Handshake_SPI0_TX

3. Call RamVectorTableUpdate() to register the TX GDMA interrupt handler.

4. Call GDMA_INTConfig() to enable TX GDMA transfer complete interrupt GDMA_INT_Transfer.

5. Call NVIC_Init() to enable NVIC of TX GDMA.

RX DMA Initialization Flow

The initialization flow for peripherals can refer to Initialization Flow.

SPI RX DMA initialization flow is shown in the following figure.

SPI RX DMA Initialization Flow Chart

1. Initialize the GDMA peripheral:

   1. Define the GDMA_InitTypeDef type GDMA_InitStruct, and call GDMA_StructInit() to pre-fill GDMA_InitStruct with default values.

   2. Modify the GDMA_InitStruct parameters as needed. The GDMA initialization parameter configuration is shown in the table below.

   3. Call GDMA_Init() to initialize the GDMA peripheral.

   GDMA Initialization Parameters

   GDMA Hardware Parameters	Setting in the GDMA_InitStruct	GDMA
   Channel Num	GDMA_InitTypeDef::GDMA_ChannelNum	SPI_RX_DMA_CHANNEL_NUM
   Transfer Direction	GDMA_InitTypeDef::GDMA_DIR	GDMA_DIR_PeripheralToMemory
   Buffer Size	GDMA_InitTypeDef::GDMA_BufferSize	DMA_BUFFER_SIZE
   Source Address Increment or Decrement	GDMA_InitTypeDef::GDMA_SourceInc	DMA_SourceInc_Fix
   Destination Address Increment or Decrement	GDMA_InitTypeDef::GDMA_DestinationInc	DMA_DestinationInc_Inc
   Source Data Size	GDMA_InitTypeDef::GDMA_SourceDataSize	GDMA_DataSize_Byte
   Destination Data Size	GDMA_InitTypeDef::GDMA_DestinationDataSize	GDMA_DataSize_Byte
   Source Burst Transaction Length	GDMA_InitTypeDef::GDMA_SourceMsize	GDMA_Msize_32
   Destination Burst Transaction Length	GDMA_InitTypeDef::GDMA_DestinationMsize	GDMA_Msize_32
   Source Address	GDMA_InitTypeDef::GDMA_SourceAddr	SPI0_HS->DR
   Destination Address	GDMA_InitTypeDef::GDMA_DestinationAddr	readbuf
   Source Handshake	GDMA_InitTypeDef::GDMA_SourceHandshake	GDMA_Handshake_SPI0_RX

2. Call RamVectorTableUpdate() to register the RX GDMA interrupt handler.

3. Call GDMA_INTConfig() to enable RX GDMA transfer complete interrupt GDMA_INT_Transfer.

4. Call NVIC_Init() to enable NVIC of RX GDMA.

Functional Implementation

Master Receive Data by DMA

1. Call SPI_GDMACmd() to disable and then enable SPI GDMA RX Function.

2. Call GDMA_Cmd() to enable RX DMA transfers.

3. When GDMA transfer is completed, transfer complete interrupt is triggered. Then call GDMA_ClearINTPendingBit() to clear GDMA_INT_Transfer interrupt.

Master Send Data by DMA

1. Call SPI_GDMACmd() to disable and then enable SPI GDMA TX Function.

2. Call GDMA_Cmd() to enable TX DMA transfers.

3. When GDMA transfer is completed, transfer complete interrupt is triggered. Then call GDMA_ClearINTPendingBit() to clear GDMA_INT_Transfer interrupt.