GD32 串口DMA

### GD32 UART DMA Communication Example Code and Documentation For microcontrollers like the GD32 series, utilizing Direct Memory Access (DMA) can significantly enhance performance by offloading data transfer tasks from the CPU to a dedicated hardware block. This is particularly useful when handling serial communications through Universal Asynchronous Receiver Transmitter (UART). The implementation of such functionality requires configuring both the UART peripheral and the DMA controller properly. Below is an example demonstrating how to set up UART communication using DMA on a GD32 device: #### Configuration Steps for UART with DMA To configure UART with DMA, one must initialize several registers within the MCU that control these peripherals' operation modes and parameters. Here’s what needs attention during setup: - Enable clocks for GPIOs connected to TX/RX pins as well as those required by USARTx and DMAn. - Configure pin functions so they operate correctly under chosen alternate function settings. - Set baud rate according to desired transmission speed while ensuring it matches between sender/receiver pairs. - Initialize DMA channels responsible for transferring received/transmitted bytes automatically without continuous intervention from software interrupts or polling loops. ```c #include "gd32f1x0.h" void uart_dma_init(void){ /* Enable clock */ rcu_periph_clock_enable(RCU_GPIOA); rcu_periph_clock_enable(RCU_USART0); rcu_periph_clock_enable(RCU_DMA0); /* Configure PA9(TX),PA10(RX) as alternate function push-pull */ gpio_mode_set(GPIOA,GPIO_MODE_AF,GPIO_PUPD_NONE,GPIO_PIN_9|GPIO_PIN_10); gpio_output_options_set(GPIOA,GPIO_OTYPE_PP,GPIO_OSPEED_50MHZ,GPIO_PIN_9|GPIO_PIN_10); /* Configure usart */ usart_deinit(USART0); usart_baudrate_set(USART0,115200); // Baud Rate Setting usart_word_length_set(USART0,USART_WL_8BIT); usart_stop_bit_set(USART0,USART_STB_1BIT); usart_parity_config(USART0,USART_PM_NONE); usart_hardware_flow_rts_config(USART0,USART_RTS_DISABLE); usart_hardware_flow_cts_config(USART0,USART_CTS_DISABLE); usart_receive_config(USART0,USART_RECEIVE_ENABLE); usart_transmit_config(USART0,USART_TRANSMIT_ENABLE); /* Configure DMA channel */ dma_parameter_struct dma_initstructure; nvic_irq_enable(DMA_Channel4_IRQn, 0, 0); dma_deinit(DMA0,DMA_CHANNEL4); dma_initstructure.direction=DMA_MEMORY_TO_PERIPHERAL; dma_initstructure.memory_addr=(uint32_t)&txbuffer[0]; dma_initstructure.memory_inc=DMA_MEMORY_INCREASE_ENABLE; dma_initstructure.periph_addr=(uint32_t)&(USART_DATA_REG_VAL(USART0)); dma_initstructure.periph_inc=DMA_PERIPH_INCREASE_DISABLE; dma_initstructure.priority=DMA_PRIORITY_HIGH; dma_initstructure.number=len; dma_init(DMA0,DMA_CHANNEL4,&dma_initstructure); } /* Function call after configuration */ usart_dma_transmit_config(USART0,USART_DMATransmit_Enable); ``` This code snippet initializes necessary configurations including enabling related clocks, setting up GPIO functionalities, specifying UART properties such as word length and stop bits, disabling flow controls not needed here, activating reception and transmission capabilities, preparing DMA transfers towards/from memory buffers associated with specific addresses linked directly into corresponding UART registers where actual byte streams will be written/read out eventually[^1]. --related questions-- 1. How does FIFO work alongside DMA in improving data throughput? 2. What are some common issues encountered when implementing UART over DMA? 3. Can you provide more details about Desktop Management Interface mentioned earlier? 4. Is there any difference between SMBIOS versions concerning information exportation via sysfs? 5. Which parts of PowerMac peripherals emulate better suited for virtualization environments compared to others listed previously?