STM32 drives wireless NRF24L01 to complete serial port data transmission

 /****************************************************** ******************************
* Function Name: USART2_IRQHandler
* Description: This function handles USART2 global interrupt request.
* Input: None
* Output: None
* Return: None
****************************************** *************************************/
extern u16 Uart2_Get_Flag;
extern u8 Uart2_Get_Data;
extern u8 TX_BUF[ 256];
void USART2_IRQHandler(void)
{
 //Receive interrupt
if(USART_GetITStatus(USART2,USART_IT_RXNE)==SET)
 {
  Timer2=500; //After 500MS nfr2401 sends
  USART_ClearITPendingBit(USART2,USART_IT_RXNE);
  TX_BUF[Uart2_Get_Flag]=USART_ReceiveData( USART2);
  Uart2_Get_Flag++;
  //USART2_Puts(TX_BUF); 
 }
 
 //Overflow - if overflow occurs, read SR first, then read DR register to clear the problem of continuous interruption
 if(USART_GetFlagStatus(USART2,USART_FLAG_ORE)==SET)
 {
  USART_ClearFlag(USART2 ,USART_FLAG_ORE); //read SR
  USART_ReceiveData(USART2); //read DR
 }
}

In the external interrupt, at least two transmissions can be made at a time. The first time RX_NU==1 is used to receive the data length of this transmission to intercept the effective string length. The second time RX_NU==2 receives the data and puts it into the array. If the data is longer than 32 bytes, it will be transmitted in multiple times. A timeout mechanism is introduced. If the transmission is not completed after 200/500 MS (RX_NU is equal to 1 again), the receiving data is abandoned and the new string length is directly received. This mechanism is very important but needs to be improved.

The same is true for the serial port. If there is no new data in 500MS, it means that the serial port has completed receiving the data and then sends the data. Uart2_Get_Flag is of course the serial length.

For NRF24L01, you can refer to its data sheet, which is all in Chinese. It’s easy to explain~~I won’t mention it here.

#ifndef _API_DEF_
#define _API_DEF_

// Define interface to nRF24L01

//* Define SPI pins
/*sbit CE = P1^0; // Chip Enable pin signal (output)
sbit CSN = P1^1; // Slave Select pin, (output to CSN, nRF24L01)
sbit IRQ = P1^3 ; // Interrupt signal, from nRF24L01 (input)
sbit MISO = P1^4; // Master In, Slave Out pin (input)
sbit MOSI = P1^5; // Serial Clock pin, (output)
sbit SCK = P1^ 7; // Master Out, Slave In pin (output)
*/

// SPI(nRF24L01) commands
#define RF_READ_REG 0x00 // Define read command to register
#define RF_WRITE_REG 0x20 // Define write command to register
#define RD_RX_PLOAD 0x61 // Define RX payload register address
#define WR_TX_PLOAD 0xA0 // Define TX payload register address
#define FLUSH_TX 0xE1 // Define flush TX register command
#define FLUSH_RX 0xE2 // Define flush RX register command
#define REUSE_TX_PL 0xE3 // Define reuse TX payload register command
#define NOP 0xFF // Define No Operation, might be used to read status register

// SPI(nRF24L01) registers(addresses)
#define CONFIG 0x00 // 'Config' register address
#define EN_AA 0x01 // 'Enable Auto Acknowledgment' register address
#define EN_RXADDR 0x02 // 'Enabled RX addresses' register address
#define SETUP_AW 0x03 // 'Setup address width' register address
#define SETUP_RETR 0x04 // 'Setup Auto. Retrans' register address
#define RF_CH 0x05 // 'RF channel' register address
#define RF_SETUP 0x06 // 'RF setup' register address
#define STATUS 0x07 // 'Status' register address
#define OBSERVE_TX 0x08 // 'Observe TX' register address
#define CD 0x09 // 'Carrier Detect' register address
#define RX_ADDR_P0 0x0A // 'RX address pipe0' register address
#define RX_ADDR_P1 0x0B // 'RX address pipe1' register address
#define RX_ADDR_P2 0x0C // 'RX address pipe2' register address
#define RX_ADDR_P3 0x0D // 'RX address pipe3' register address
#define RX_ADDR_P4 0x0E // 'RX address pipe4' register address
#define RX_ADDR_P5 0x0F // 'RX address pipe5' register address
#define TX_ADDR 0x10 // 'TX address' register address
#define RX_PW_P0 0x11 // 'RX payload width, pipe0 ' register address
#define RX_PW_P1 0x12 // 'RX payload width, pipe1' register address
#define RX_PW_P2 0x13 // 'RX payload width, pipe2' register address
#define RX_PW_P3 0x14 // 'RX payload width, pipe3' register address
#define RX_PW_P4 0x15 // 'RX payload width, pipe4' register address
#define RX_PW_P5 0x16 // 'RX payload width, pipe5' register address
#define FIFO_STATUS 0x17 // 'FIFO Status Register' register address

#endif /* _API_DEF_ */

extern u8 SPI_RW(u8 byte); #define TX_ADR_WIDTH 5 // 5-byte width transmit / receive address
#define TX_PLOAD_WIDTH
32 // Receive byte number 32 words #define uchar u8 /   * control pin */ #define CE_H GPIOC->BSRR=GPIO_Pin_4 #define CE_L GPIOC->BRR=GPIO_Pin_4 

#define CSN_H GPIOB->BSRR=GPIO_Pin_2
#define CSN_L GPIOB->BRR=GPIO_Pin_2 

#define IRQ (GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_0))  
#define IRQ_H GPIOB->BSRR=GPIO_Pin_0

#define LED1 GPIOB->BSRR=GPIO_Pin_12
#define LED0 GPIOB->BRR=GPIO_Pin_12
#define LED GPIOB->ODR=((GPIOD->ODR)^GPIO_Pin_12)

#define RX_DR ((sta>>6)&0X01)
#define TX_DS ((sta>>5)&0X01)
#define MAX_RT ((sta>>4)&0X01)

//USART
extern void USART2_Putc(unsigned char c);
extern void USART2_Puts(char * str);
extern u16 Uart2_Get_Flag; //Data length received by serial port 2
extern u8 Uart2_Get_Data; //Data received by serial port 2
#endif

Pay attention to the priority setting before interruption

#include "STM32Lib\\stm32f10x.h" 
void NVIC_Configuration(void)
{
 NVIC_InitTypeDef NVIC_InitStructure;
 
 /* Configure interrupt usage combination 1*/
 NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
 
 /* EXTI0*/
 NVIC_InitStructure.NVIC_IRQChannel =EXTI0_IR Qn;
 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
 NVIC_Init(&NVIC_InitStructure);

  /* Configure one bit for preemption priority */
 NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
 
 /*UART2*/
 NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority
 = 0;
 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
 NVIC_Init(&NVIC_InitStructure);
  
}