前言
G4板载了一块M24C02(eeprom)和一块MCP4017(可编程电阻)，省赛中多考M24C02，本篇文章讲述如何用软件I2驱动M24C02。

I2C
1.原理图以及配置元素



分析:由图可知，PB6为I2C的SCL线，PB7为I2C的SDA线


2.CubeMx的配置步骤



大赛是提供了I2C的驱动的这里我们只需要把两个引脚设置输出模式就行了，不再需要其他步骤。


3.生成工程





将红框中的两个文件复制黏贴到工程文件夹中的bsp文件夹中并改名为i2c.c和i2c.h。



在bsp文件中新建i2cc.c和i2c.h文件
打开工程将两个文件添加到工程中去



至此工程就建立完毕了

4.测试代码
i2c.h:

1. #ifndef __I2C_H
   
2. #define __I2C_H
   
3. 
   
4. #include "main.h"
   
5. 
   
6. void I2CStart(void);
   
7. void I2CStop(void);
   
8. unsigned char I2CWaitAck(void);
   
9. void I2CSendAck(void);
   
10. void I2CSendNotAck(void);
    
11. void I2CSendByte(unsigned char cSendByte);
    
12. unsigned char I2CReceiveByte(void);
    
13. void I2CInit(void);
    
14. 
    
15. /*******下方为自己添加的函数声明**************/
    
16. unsigned char eeprom_read(unsigned char addr);
    
17. void eeprom_write(unsigned char addr, unsigned char dat);
    
18. 
    
19. #endif
    
20. 
    

复制代码

i2c.c:

1. #include "i2c.h"
   
2. 
   
3. #define DELAY_TIME        20
   
4. 
   
5. 
   
6. /**
   
7.   * @brief SDA线输入模式配置
   
8.   * @param None
   
9.   * @retval None
   
10.   */
    
11. void SDA_Input_Mode()
    
12. {
    
13.     GPIO_InitTypeDef GPIO_InitStructure = {0};
    
14. 
    
15.     GPIO_InitStructure.Pin = GPIO_PIN_7;
    
16.     GPIO_InitStructure.Mode = GPIO_MODE_INPUT;
    
17.     GPIO_InitStructure.Pull = GPIO_PULLUP;
    
18.     GPIO_InitStructure.Speed = GPIO_SPEED_FREQ_HIGH;
    
19.     HAL_GPIO_Init(GPIOB, &GPIO_InitStructure);
    
20. }
    
21. 
    
22. /**
    
23.   * @brief SDA线输出模式配置
    
24.   * @param None
    
25.   * @retval None
    
26.   */
    
27. void SDA_Output_Mode()
    
28. {
    
29.     GPIO_InitTypeDef GPIO_InitStructure = {0};
    
30. 
    
31.     GPIO_InitStructure.Pin = GPIO_PIN_7;
    
32.     GPIO_InitStructure.Mode = GPIO_MODE_OUTPUT_OD;
    
33.     GPIO_InitStructure.Pull = GPIO_NOPULL;
    
34.     GPIO_InitStructure.Speed = GPIO_SPEED_FREQ_HIGH;
    
35.     HAL_GPIO_Init(GPIOB, &GPIO_InitStructure);
    
36. }
    
37. 
    
38. /**
    
39.   * @brief SDA线输出一个位
    
40.   * @param val 输出的数据
    
41.   * @retval None
    
42.   */
    
43. void SDA_Output( uint16_t val )
    
44. {
    
45.     if ( val )
    
46.     {
    
47.         GPIOB->BSRR |= GPIO_PIN_7;
    
48.     }
    
49.     else
    
50.     {
    
51.         GPIOB->BRR |= GPIO_PIN_7;
    
52.     }
    
53. }
    
54. 
    
55. /**
    
56.   * @brief SCL线输出一个位
    
57.   * @param val 输出的数据
    
58.   * @retval None
    
59.   */
    
60. void SCL_Output( uint16_t val )
    
61. {
    
62.     if ( val )
    
63.     {
    
64.         GPIOB->BSRR |= GPIO_PIN_6;
    
65.     }
    
66.     else
    
67.     {
    
68.         GPIOB->BRR |= GPIO_PIN_6;
    
69.     }
    
70. }
    
71. 
    
72. /**
    
73.   * @brief SDA输入一位
    
74.   * @param None
    
75.   * @retval GPIO读入一位
    
76.   */
    
77. uint8_t SDA_Input(void)
    
78. {
    
79.         if(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_7) == GPIO_PIN_SET){
    
80.                 return 1;
    
81.         }else{
    
82.                 return 0;
    
83.         }
    
84. }
    
85. 
    
86. 
    
87. /**
    
88.   * @brief I2C的短暂延时
    
89.   * @param None
    
90.   * @retval None
    
91.   */
    
92. static void delay1(unsigned int n)
    
93. {
    
94.     uint32_t i;
    
95.     for ( i = 0; i < n; ++i);
    
96. }
    
97. 
    
98. /**
    
99.   * @brief I2C起始信号
    
100.   * @param None
     
101.   * @retval None
     
102.   */
     
103. void I2CStart(void)
     
104. {
     
105.     SDA_Output(1);
     
106.     delay1(DELAY_TIME);
     
107.     SCL_Output(1);
     
108.     delay1(DELAY_TIME);
     
109.     SDA_Output(0);
     
110.     delay1(DELAY_TIME);
     
111.     SCL_Output(0);
     
112.     delay1(DELAY_TIME);
     
113. }
     
114. 
     
115. /**
     
116.   * @brief I2C结束信号
     
117.   * @param None
     
118.   * @retval None
     
119.   */
     
120. void I2CStop(void)
     
121. {
     
122.     SCL_Output(0);
     
123.     delay1(DELAY_TIME);
     
124.     SDA_Output(0);
     
125.     delay1(DELAY_TIME);
     
126.     SCL_Output(1);
     
127.     delay1(DELAY_TIME);
     
128.     SDA_Output(1);
     
129.     delay1(DELAY_TIME);
     
130. 
     
131. }
     
132. 
     
133. /**
     
134.   * @brief I2C等待确认信号
     
135.   * @param None
     
136.   * @retval None
     
137.   */
     
138. unsigned char I2CWaitAck(void)
     
139. {
     
140.     unsigned short cErrTime = 5;
     
141.     SDA_Input_Mode();
     
142.     delay1(DELAY_TIME);
     
143.     SCL_Output(1);
     
144.     delay1(DELAY_TIME);
     
145.     while(SDA_Input())
     
146.     {
     
147.         cErrTime--;
     
148.         delay1(DELAY_TIME);
     
149.         if (0 == cErrTime)
     
150.         {
     
151.             SDA_Output_Mode();
     
152.             I2CStop();
     
153.             return ERROR;
     
154.         }
     
155.     }
     
156.     SDA_Output_Mode();
     
157.     SCL_Output(0);
     
158.     delay1(DELAY_TIME);
     
159.     return SUCCESS;
     
160. }
     
161. 
     
162. /**
     
163.   * @brief I2C发送确认信号
     
164.   * @param None
     
165.   * @retval None
     
166.   */
     
167. void I2CSendAck(void)
     
168. {
     
169.     SDA_Output(0);
     
170.     delay1(DELAY_TIME);
     
171.     delay1(DELAY_TIME);
     
172.     SCL_Output(1);
     
173.     delay1(DELAY_TIME);
     
174.     SCL_Output(0);
     
175.     delay1(DELAY_TIME);
     
176. 
     
177. }
     
178. 
     
179. /**
     
180.   * @brief I2C发送非确认信号
     
181.   * @param None
     
182.   * @retval None
     
183.   */
     
184. void I2CSendNotAck(void)
     
185. {
     
186.     SDA_Output(1);
     
187.     delay1(DELAY_TIME);
     
188.     delay1(DELAY_TIME);
     
189.     SCL_Output(1);
     
190.     delay1(DELAY_TIME);
     
191.     SCL_Output(0);
     
192.     delay1(DELAY_TIME);
     
193. 
     
194. }
     
195. 
     
196. /**
     
197.   * @brief I2C发送一个字节
     
198.   * @param cSendByte 需要发送的字节
     
199.   * @retval None
     
200.   */
     
201. void I2CSendByte(unsigned char cSendByte)
     
202. {
     
203.     unsigned char  i = 8;
     
204.     while (i--)
     
205.     {
     
206.         SCL_Output(0);
     
207.         delay1(DELAY_TIME);
     
208.         SDA_Output(cSendByte & 0x80);
     
209.         delay1(DELAY_TIME);
     
210.         cSendByte += cSendByte;
     
211.         delay1(DELAY_TIME);
     
212.         SCL_Output(1);
     
213.         delay1(DELAY_TIME);
     
214.     }
     
215.     SCL_Output(0);
     
216.     delay1(DELAY_TIME);
     
217. }
     
218. 
     
219. /**
     
220.   * @brief I2C接收一个字节
     
221.   * @param None
     
222.   * @retval 接收到的字节
     
223.   */
     
224. unsigned char I2CReceiveByte(void)
     
225. {
     
226.     unsigned char i = 8;
     
227.     unsigned char cR_Byte = 0;
     
228.     SDA_Input_Mode();
     
229.     while (i--)
     
230.     {
     
231.         cR_Byte += cR_Byte;
     
232.         SCL_Output(0);
     
233.         delay1(DELAY_TIME);
     
234.         delay1(DELAY_TIME);
     
235.         SCL_Output(1);
     
236.         delay1(DELAY_TIME);
     
237.         cR_Byte |=  SDA_Input();
     
238.     }
     
239.     SCL_Output(0);
     
240.     delay1(DELAY_TIME);
     
241.     SDA_Output_Mode();
     
242.     return cR_Byte;
     
243. }
     
244. 
     
245. //
     
246. void I2CInit(void)
     
247. {
     
248.                 GPIO_InitTypeDef GPIO_InitStructure = {0};
     
249. 
     
250.     GPIO_InitStructure.Pin = GPIO_PIN_7 | GPIO_PIN_6;
     
251.     GPIO_InitStructure.Mode = GPIO_MODE_OUTPUT_PP;
     
252.     GPIO_InitStructure.Pull = GPIO_PULLUP;
     
253.     GPIO_InitStructure.Speed = GPIO_SPEED_FREQ_HIGH;
     
254.     HAL_GPIO_Init(GPIOB, &GPIO_InitStructure);
     
255. }
     
256. 
     
257. /**************以上是大赛提供的驱动**************************/
     
258. 
     
259. 
     
260. /***********以下是自己写的对24C02的读写操作******************/
     
261. 
     
262. unsigned char eeprom_read(unsigned char addr)
     
263. {
     
264.         unsigned char dat;
     
265.         
     
266.         I2CStart();
     
267.         I2CSendByte(0xa0);
     
268.         I2CWaitAck();
     
269.         I2CSendByte(addr);
     
270.         I2CWaitAck();
     
271.         I2CStop();
     
272.         
     
273.         I2CStart();
     
274.         I2CSendByte(0xa1);
     
275.         I2CWaitAck();
     
276.         dat = I2CReceiveByte();
     
277.         I2CWaitAck();
     
278.         I2CStop();
     
279.         
     
280.         return dat;
     
281. }
     
282. 
     
283. 
     
284. void eeprom_write(unsigned char addr, unsigned char dat)
     
285. {
     
286.         I2CStart();
     
287.         I2CSendByte(0xa0);
     
288.         I2CWaitAck();
     
289.         I2CSendByte(addr);
     
290.         I2CWaitAck();
     
291.         I2CSendByte(dat);
     
292.         I2CWaitAck();
     
293.         I2CStop();
     
294. }
     
295. 
     

复制代码

main.c:

1. /* USER CODE BEGIN Header */
   
2. /**
   
3.   ******************************************************************************
   
4.   * @file           : main.c
   
5.   * @brief          : Main program body
   
6.   ******************************************************************************
   
7.   * @attention
   
8.   *
   
9.   * <h2><center>© Copyright (c) 2023 STMicroelectronics.
   
10.   * All rights reserved.</center></h2>
    
11.   *
    
12.   * This software component is licensed by ST under BSD 3-Clause license,
    
13.   * the "License"; You may not use this file except in compliance with the
    
14.   * License. You may obtain a copy of the License at:
    
15.   *                        opensource.org/licenses/BSD-3-Clause
    
16.   *
    
17.   ******************************************************************************
    
18.   */
    
19. /* USER CODE END Header */
    
20. /* Includes ------------------------------------------------------------------*/
    
21. #include "main.h"
    
22. #include "adc.h"
    
23. #include "tim.h"
    
24. #include "gpio.h"
    
25. 
    
26. /* Private includes ----------------------------------------------------------*/
    
27. /* USER CODE BEGIN Includes */
    
28. #include "lcd.h"
    
29. #include "badc.h"
    
30. #include "stdio.h"
    
31. #include "i2c.h"
    
32. #include "interrupt.h"
    
33. /* USER CODE END Includes */
    
34. 
    
35. /* Private typedef -----------------------------------------------------------*/
    
36. /* USER CODE BEGIN PTD */
    
37. 
    
38. /* USER CODE END PTD */
    
39. 
    
40. /* Private define ------------------------------------------------------------*/
    
41. /* USER CODE BEGIN PD */
    
42. /* USER CODE END PD */
    
43. 
    
44. /* Private macro -------------------------------------------------------------*/
    
45. /* USER CODE BEGIN PM */
    
46. 
    
47. /* USER CODE END PM */
    
48. 
    
49. /* Private variables ---------------------------------------------------------*/
    
50. 
    
51. /* USER CODE BEGIN PV */
    
52. extern struct keys key[4];
    
53. unsigned char adc1_L, adc1_H;
    
54. /* USER CODE END PV */
    
55. 
    
56. /* Private function prototypes -----------------------------------------------*/
    
57. void SystemClock_Config(void);
    
58. /* USER CODE BEGIN PFP */
    
59. 
    
60. /* USER CODE END PFP */
    
61. 
    
62. /* Private user code ---------------------------------------------------------*/
    
63. /* USER CODE BEGIN 0 */
    
64. 
    
65. /* USER CODE END 0 */
    
66. 
    
67. /**
    
68.   * @brief  The application entry point.
    
69.   * @retval int
    
70.   */
    
71. int main(void)
    
72. {
    
73.   /* USER CODE BEGIN 1 */
    
74. 
    
75.   /* USER CODE END 1 */
    
76. 
    
77.   /* MCU Configuration--------------------------------------------------------*/
    
78. 
    
79.   /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
    
80.   HAL_Init();
    
81. 
    
82.   /* USER CODE BEGIN Init */
    
83. 
    
84.   /* USER CODE END Init */
    
85. 
    
86.   /* Configure the system clock */
    
87.   SystemClock_Config();
    
88. 
    
89.   /* USER CODE BEGIN SysInit */
    
90. 
    
91.   /* USER CODE END SysInit */
    
92. 
    
93.   /* Initialize all configured peripherals */
    
94.   MX_GPIO_Init();
    
95.   MX_TIM3_Init();
    
96.   MX_TIM16_Init();
    
97.   MX_TIM17_Init();
    
98.   MX_ADC1_Init();
    
99.   MX_ADC2_Init();
    
100.   /* USER CODE BEGIN 2 */
     
101.         LCD_Init();
     
102.         LCD_Clear(Black);
     
103.         LCD_SetBackColor(Black);
     
104.         LCD_SetTextColor(White);
     
105.         HAL_TIM_Base_Start_IT(&htim3);
     
106.   /* USER CODE END 2 */
     
107. 
     
108.   /* Infinite loop */
     
109.   /* USER CODE BEGIN WHILE */
     
110.   while (1)
     
111.   {
     
112.     /* USER CODE END WHILE */
     
113. 
     
114.     /* USER CODE BEGIN 3 */
     
115.                 char text[30];
     
116.                 unsigned int adc1, adc2;
     
117.                 adc1 = getADC(&hadc1);
     
118.                 sprintf(text, "    V1:%.2f", adc1 * 3.3 / 4096);
     
119.                 LCD_DisplayStringLine(Line4, (unsigned char *)text);
     
120.                 adc2 = getADC(&hadc2);
     
121.                 sprintf(text, "    V2:%.2f", adc2 * 3.3 / 4096);
     
122.                 LCD_DisplayStringLine(Line5, (unsigned char *)text);
     
123.                 if(key[0].single_flag) //短按写入
     
124.                 {
     
125.                         adc1_L = adc1 & 0xff;
     
126.                         adc1_H = adc1 >> 8;
     
127.                         eeprom_write(1, adc1_L);
     
128.                         HAL_Delay(10);
     
129.                         eeprom_write(2, adc1_H);
     
130.                         key[0].single_flag = 0;
     
131.                 }
     
132.                 if(key[0].long_flag) //长按读出
     
133.                 {
     
134.                         char text[30];
     
135.                         unsigned int eep_temp = (eeprom_read(2) << 8) + eeprom_read(1);
     
136.                         sprintf(text, "    ADC_eep=%.2f", eep_temp * 3.3 / 4096);
     
137.                         LCD_DisplayStringLine(Line8, (unsigned char *)text);
     
138.                         key[0].long_flag = 0;        
     
139.                 }
     
140.   }
     
141.   /* USER CODE END 3 */
     
142. }
     
143. 
     
144. /**
     
145.   * @brief System Clock Configuration
     
146.   * @retval None
     
147.   */
     
148. void SystemClock_Config(void)
     
149. {
     
150.   RCC_OscInitTypeDef RCC_OscInitStruct = {0};
     
151.   RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
     
152.   RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
     
153. 
     
154.   /** Configure the main internal regulator output voltage
     
155.   */
     
156.   HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1);
     
157.   /** Initializes the RCC Oscillators according to the specified parameters
     
158.   * in the RCC_OscInitTypeDef structure.
     
159.   */
     
160.   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
     
161.   RCC_OscInitStruct.HSEState = RCC_HSE_ON;
     
162.   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
     
163.   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
     
164.   RCC_OscInitStruct.PLL.PLLM = RCC_PLLM_DIV3;
     
165.   RCC_OscInitStruct.PLL.PLLN = 20;
     
166.   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
     
167.   RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;
     
168.   RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;
     
169.   if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
     
170.   {
     
171.     Error_Handler();
     
172.   }
     
173.   /** Initializes the CPU, AHB and APB buses clocks
     
174.   */
     
175.   RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
     
176.                               |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
     
177.   RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
     
178.   RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
     
179.   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
     
180.   RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
     
181. 
     
182.   if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
     
183.   {
     
184.     Error_Handler();
     
185.   }
     
186.   /** Initializes the peripherals clocks
     
187.   */
     
188.   PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_ADC12;
     
189.   PeriphClkInit.Adc12ClockSelection = RCC_ADC12CLKSOURCE_SYSCLK;
     
190.   if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
     
191.   {
     
192.     Error_Handler();
     
193.   }
     
194. }
     
195. 
     
196. /* USER CODE BEGIN 4 */
     
197. 
     
198. /* USER CODE END 4 */
     
199. 
     
200. /**
     
201.   * @brief  This function is executed in case of error occurrence.
     
202.   * @retval None
     
203.   */
     
204. void Error_Handler(void)
     
205. {
     
206.   /* USER CODE BEGIN Error_Handler_Debug */
     
207.   /* User can add his own implementation to report the HAL error return state */
     
208.   __disable_irq();
     
209.   while (1)
     
210.   {
     
211.   }
     
212.   /* USER CODE END Error_Handler_Debug */
     
213. }
     
214. 
     
215. #ifdef  USE_FULL_ASSERT
     
216. /**
     
217.   * @brief  Reports the name of the source file and the source line number
     
218.   *         where the assert_param error has occurred.
     
219.   * @param  file: pointer to the source file name
     
220.   * @param  line: assert_param error line source number
     
221.   * @retval None
     
222.   */
     
223. void assert_failed(uint8_t *file, uint32_t line)
     
224. {
     
225.   /* USER CODE BEGIN 6 */
     
226.   /* User can add his own implementation to report the file name and line number,
     
227.      ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
     
228.   /* USER CODE END 6 */
     
229. }
     
230. #endif /* USE_FULL_ASSERT */
     
231. 
     
232. /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
     
233. 
     

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