IR GDMA Transmit

This sample uses the IR peripheral to send data by utilizing GDMA, achieving the data transmission function.

The GDMA will transfer predefined IR data from memory to the IR TX FIFO, and upon completion, it will trigger a GDMA interrupt.

A logic analyzer can be used to observe whether the IR transmitted data meets expectations.

Requirements

For requirements, please refer to the Requirements.

Wiring

Connect the IR transmit pin P2_5 to the logic analyzer.

Configurations

The following macro can be configured to modify the pin definitions.
```
#define IR_TX_PIN                       P2_5
```

The following macros can be configured to modify the GDMA channel settings.

#define IO_TEST_GDMA_CHANNEL_MUM        1           /*< Set this macro to select the GDMA Channel num. */

// Set the following macros to modify the GDMA Channel configurations.
#if (IO_TEST_GDMA_CHANNEL_MUM == 0)
#define IO_TEST_GDMA_Channel                GDMA_Channel0
#define IO_TEST_GDMA_Channel_IRQn           GDMA0_Channel0_IRQn
#define IO_TEST_GDMA_Channel_Handler        GDMA0_Channel0_Handler
#elif IO_TEST_GDMA_CHANNEL_MUM == 1
#define IO_TEST_GDMA_Channel                GDMA_Channel1
#define IO_TEST_GDMA_Channel_IRQn           GDMA0_Channel1_IRQn
#define IO_TEST_GDMA_Channel_Handler        GDMA0_Channel1_Handler
#elif IO_TEST_GDMA_CHANNEL_MUM == 2
#define IO_TEST_GDMA_Channel                GDMA_Channel2
#define IO_TEST_GDMA_Channel_IRQn           GDMA0_Channel2_IRQn
#define IO_TEST_GDMA_Channel_Handler        GDMA0_Channel2_Handler
#elif IO_TEST_GDMA_CHANNEL_MUM == 3
#define IO_TEST_GDMA_Channel                GDMA_Channel3
#define IO_TEST_GDMA_Channel_IRQn           GDMA0_Channel3_IRQn
#define IO_TEST_GDMA_Channel_Handler        GDMA0_Channel3_Handler
#endif

The following macros can be configured to modify the GDMA data transfer length.

#define IO_TEST_GDMA_TRANSFER_SIZE          IR_DATA_SIZE_MAX                       /*< Set this macro to modify the transfer size. */
#define IR_DATA_SIZE_MAX                    68

Building and Downloading

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

Experimental Verification

Observe the IR transmit waveform with a logic analyzer.

Here should be a picture of the IR sending waveforms — IR Transmit Waveform

Code Overview

This section introduces the code and process description for initialization and corresponding function implementation in the sample.

Source Code Directory

The directory for project file and source code are as follows:

Project directory: sdk\samples\peripheral\ir\tx+gdma\proj
Source code directory: sdk\samples\peripheral\ir\tx+gdma\src

Initialization

The initialization flow for peripherals can refer to Initialization Flow in General Introduction.

Call Pad_Config() and Pinmux_Config() to configure the PAD and PINMUX of the corresponding pins.

void board_ir_init(void)
{
    Pad_Config(IR_TX_PIN, PAD_PINMUX_MODE, PAD_IS_PWRON, PAD_PULL_NONE, PAD_OUT_ENABLE, PAD_OUT_LOW);

    Pinmux_Config(IR_TX_PIN, IRDA_TX);
}

Call RCC_PeriphClockCmd() to enable the IR clock.
Initialize the IR peripheral:
1. Define the IR_InitTypeDef type IR_InitStruct, and call IR_StructInit() to pre-fill IR_InitStruct with default values.
2. Modify the IR_InitStruct parameters as needed. The IR initialization parameter configuration is shown in the table below.
3. Call IR_Init() to initialize the IR peripheral.

IR Initialization Parameters
IR Hardware Parameters	Setting in the `IR_InitStruct`	IR
Sample Clock	`IR_InitTypeDef::IR_Freq`	38000
IR Duty Cycle	`IR_InitTypeDef::IR_DutyCycle`	3
IR Mode	`IR_InitTypeDef::IR_Mode`	`IR_MODE_TX`
IR Tx GDMA Enable	`IR_InitTypeDef::IR_TxDmaEn`	`ENABLE`
IR Tx Waterlevel	`IR_InitTypeDef::IR_TxWaterLevel`	15

Call RCC_PeriphClockCmd() to enable the IR clock.
Initialize the GDMA peripheral:
1. Define a 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 initialization parameters for the GDMA channel are configured as shown in the table below. Call GDMA_Init() to initialize the GDMA peripheral.
3. Configure the GDMA total transfer complete interrupt GDMA_INT_Transfer and NVIC. For NVIC configurations, refer to Interrupt Configuration.

GDMA Initialization Parameters
GDMA Hardware Parameters	Setting in the `GDMA_InitStruct`	GDMA Channel
Channel Num	`GDMA_InitTypeDef::GDMA_ChannelNum`	1
Transfer Direction	`GDMA_InitTypeDef::GDMA_DIR`	`GDMA_DIR_MemoryToPeripheral`
Buffer Size	`GDMA_InitTypeDef::GDMA_BufferSize`	`IO_TEST_GDMA_TRANSFER_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_Word`
Destination Data Size	`GDMA_InitTypeDef::GDMA_DestinationDataSize`	`GDMA_DataSize_Word`
Source Burst Transaction Length	`GDMA_InitTypeDef::GDMA_SourceMsize`	`GDMA_Msize_1`
Destination Burst Transaction Length	`GDMA_InitTypeDef::GDMA_DestinationMsize`	`GDMA_Msize_1`
Source Address	`GDMA_InitTypeDef::GDMA_SourceAddr`	`GDMA_Send_Buf`
Destination Address	`GDMA_InitTypeDef::GDMA_DestinationAddr`	`(&IR->IR_TX_FIFO)`
Destination Handshake	`GDMA_InitTypeDef::GDMA_DestHandshake`	`GDMA_Handshake_IR_TX`

Functional Implementation

Define IR send data array: carrier data is represented by the number of carriers or 0x80000000, no carrier data is represented by the number of carriers or 0x00000000.

Call GDMA_Cmd() to enable the corresponding GDMA channel transmission. Call IR_Cmd() to enable the IR peripheral transmission function. GDMA transfers data from GDMA_Send_Buf to (&IR->IR_TX_FIFO).

IR_Send_Data.CarrierFreq = 38000;
IR_Send_Data.DataLen = IO_TEST_GDMA_TRANSFER_SIZE;
IR_Send_Data.DataBuf[0] =  0x80000000 | 0x200;
IR_Send_Data.DataBuf[1] =  0x00000000 | 0x100;
...
IR_Send_Data.DataBuf[IR_Send_Data.DataLen - 1] =  0x80000000 | 0x800;

/* Test data buffer */
for (uint32_t i = 0; i < IO_TEST_GDMA_TRANSFER_SIZE; i++)
{
    GDMA_Send_Buf[i] = IR_Send_Data.DataBuf[i];
}
...
IR_Cmd(IR_MODE_TX, ENABLE);

When the GDMA completes data transfer, trigger the GDMA_INT_Transfer interrupt. Within the interrupt function, print the relevant information, disable the GDMA transfer, and clear the interrupt flag.

void IO_TEST_GDMA_Channel_Handler(void)
{
    GDMA_INTConfig(IO_TEST_GDMA_CHANNEL_MUM, GDMA_INT_Transfer, DISABLE);
    GDMA_Cmd(IO_TEST_GDMA_CHANNEL_MUM, DISABLE);
    DBG_DIRECT("IO_TEST_GDMA_Channel_Handler\r\n");
    GDMA_ClearINTPendingBit(IO_TEST_GDMA_CHANNEL_MUM, GDMA_INT_Transfer);
}