BearPi Std 板从入门到放弃 - 后天篇（2）(I2C1读写EEPROM)

简介

基于 BearPi Std 板从入门到放弃 - 后天篇（1）(I2C1 读取光照强度)，使用同一个I2C接口访问EEPROM, 同时读取光照亮度
主芯片: STM32L431RCT6
LED : PC13 \ 推挽输出即可 \ 高电平点亮
串口: Usart1
I2C : I2C1
光照强度传感器：BH1750
EEPROM芯片 : AT24C02

芯片说明

BearPi 自带的扩展版 E53_SC1_智慧路灯的原理图
AT2402C 基本描述, 2Kbit, 32Page, 每个Page 8 Bytes，所以地址是0~255
AT2402C 的设备地址规则
结论
a. 结合原理图,
A0 = 1; A1 = 0; A2 =0;
写的地址 = 10100010 = 0xA2
读的地址 = 10100011 = 0xA3

b. 2Kbit, 32Page, 每个Page 8 Bytes，所以地址是0~255

步骤

基于前面文章, 创建工程
添加读写代码

#define AT24C02_WRITE_ADDRESS 0xA2
#define AT24C02_READ_ADDRESS 0xA3

/* 写单个字节 */
uint8_t AT24C02_Write_Byte(uint16_t addr, uint8_t *dat)
{
	return HAL_I2C_Mem_Write(&hi2c1, AT24C02_WRITE_ADDRESS, addr, I2C_MEMADD_SIZE_8BIT, dat, 1, 0xffff);
}
/* 读取单个字节 */
uint8_t AT24C02_Read_Byte(uint16_t addr, uint8_t *buf)
{
	return HAL_I2C_Mem_Read(&hi2c1, AT24C02_READ_ADDRESS, addr, I2C_MEMADD_SIZE_8BIT, buf, 1, 0xffff);
}

/* 读多个字节 */
uint8_t AT24C02_Read_Bytes(uint16_t addr, uint8_t *buf, uint16_t bufSize)
{
	return HAL_I2C_Mem_Read(&hi2c1, AT24C02_READ_ADDRESS, addr, I2C_MEMADD_SIZE_8BIT, buf, bufSize, 0xffff);
}

int main()
{
	...
	uint8_t res = 0;
	uint8_t datTemp = 0;
	/* 写完整个EEPROM */
	for (int i = 0; i < 256; ++i)
	{
		datTemp  = i;
		res = AT24C02_Write_Byte(i, &datTemp);
		if (res)
		{
			printf("Faile To Write Address %d!\r\n", i);
		}
		HAL_Delay(10); // 写延时, 不然会失败
	}
	
	/* 读完整个EEPROM */
	for (int i = 0; i < 256; ++i)
	{
		res = AT24C02_Read_Byte(i, &datTemp);
		if (res)
		{
			printf("Faile To ReadAddress %d!\r\n", i);
		}
		else
		{
			printf("Address: %d, Value: %d\r\n", i, datTemp);
		}
	}

	while(1)
	{
		...
	}
}

Note:
可以扩展 WritePage, 1 Page 8 Bytes，可以一次性写8Bytes
例如
0(地址), 8Bytes数据; // 第一页
8(地址), 8Bytes数据; // 第二页
…
24(地址), 8Bytes数据; // 第三页

	/* 接口可以按页码, 简单写下 */
	uint8_t writePage(uint_8 pageNum, uint_8 *dat, uint_16 datSize)
	{
		uint16_t addr = 0;
		if (pageNum < 0 || pageNum >= 32)
			return 1; // HAL_ERROR;
		addr = pageNum * 8; // 每页8Bytes
		
		return HAL_I2C_Mem_Write(&hi2c1, AT24C02_READ_ADDRESS, addr, I2C_MEMADD_SIZE_8BIT, dat, datSize, 0xffff); 
	}