单片机存储芯片 W25QXX、AT24C02

一、FLASH W25QXX

(1) W25QXX芯片简介

W25Q128是华邦公司推出的一款SPI接口的NOR Flash芯片，其存储空间为128Mbit，相当于16M字节。W25Q128V芯片是串行闪存，可以通过标准/两线/四线SPI控制。W25Q128一次最多可编程256个字节。页面可以按扇区擦除、块擦除、整个芯片擦除。

W25Q128 的擦写周期多达 10W 次，具有 20 年的数据保存期限，支持电压为 2.7~3.6V，W25Q128 支持标准的 SPI，还支持双输出/四输出的 SPI，最大 SPI 时钟可以到 80Mhz（双输出时相当于 160Mhz，四输出时相当于 320M）。

W25Q128存储容量共128M-bit/ 16M-byte。

1页 = 256bytes
1 扇区 = 16页
1 块 = 16扇区

W25Q64存储容量共64M-bit/ 8M-byte。

1页 = 256bytes
1 扇区 = 16页
1 块 = 16扇区

(2) W25QXX芯片引脚说明

第1脚CS是SPI总线的片选使能接口，SPI总线支持在一条总线上连接多个芯片，为了区分当前通信的是哪个芯片，就为每个芯片连接一个独立的CS片选接口，单片机想和哪个芯片通信，就向哪个芯片的CS引脚输出低电平。
第2脚D0是SPI总线的数据输出接口。
第3脚WP是硬件写保护接口，当向此引脚输入低电平，芯片将禁止写入数据。反之，可正常写入数据。
第4脚GND是公共地。
第5脚DI是SPI总线的数据输入接口。
第6脚CLK是SPI总线的时钟输入接口。
第7脚HOLD是状态保持接口。当向此引脚输入低电平，芯片将禁止任何操作，当向此引脚输入高电平，可正常操作芯片。
第8脚VCC是电源供电接口，输入2.7-3.6V的电源。

(3) W25QXX芯片读错误原因

写数据之前Flash里面的数据不是0xFF就必须先擦除，然后才能写数据。擦除即将Flash里面的数据恢复为0xFF的过程。
上电后设备自动处于写禁用状态（Write Enable Latch, WEL为0，WEL是只读位）。在Page Program, Sector Erase, Block Erase, Chip Erase or Write Status Register instruction（页编程、区擦除、块擦除、芯片擦除或者写状态寄存器指令）之前必须先进行写使能指令。在编程、擦除、写状态寄存器指令完成后，WEL自动变成0。
　W25Q64BV是使用四线SPI兼容总线：串行时钟：（CLK），片选（CS），串行数据输入（DI），串行数据输出（DO）。标准SPI指令是MCU在CLK的上升沿使用DI输入引脚串行写指令，地址，数据到设备。在CLK的下降沿用DO输出引脚从设备读取数据或状态。
W25Q128芯片第一次接收指令集的时候不会做出响应，所以在初始化时向芯片随便发送一个指令集（如0xFF），芯片才能正常响应。（针对部分单片机）

spi_start();//读取ID前向芯片发送一个FF指令
spi_swapByte(0xFF);
spi_stop();
w25q128_readID(&ID);//正常读取ID
配置SPI：SPI的工作模式配置为 0，即 CPOL = 0，CPHA = 0
写内存时需要注意Flash的一个要点，Flash编程只能将1写为0，而不能将0写成1，写1靠擦除。所以需要在写内存的时候将内存擦除，使用内存擦除指令擦除内存（擦除的最小单位是扇区），内存变为0xFF，然后再写内存。
Flash的写的有个特性跟EEPROM一样，就是它的一页是256个Byte，也就是在写入的时候，一次最多可以写入256个字节的数据，超过了需要自行在代码中处理，一次最多编程256字节，写超的话会对当前页的前面数据进行覆盖。
写入完成之后必须要等待一定的时间，不然马上写入第二次写入会失败W25Q128_Wait_Busy(); //等待写入结束
芯片可以从当前位置读完整个芯片数据；芯片只能单页写，写之前内容需要被擦除；
写入数据程序进入硬件中断可能是堆栈溢出，比如FReeRTOS里面每一个任务分配的空间是128BYTE,超过内存卡死

(4) STM32CubeMX配置SPI通信（HAL库）

以stm32F407战舰版举例，由于战舰版和W25QXX芯片引脚已经连接完成，分别是PB3-PB5，使用cubemx配置SPI1时，但是软件会默认选择PA4-PA6复用SPI1,但是我们需要使用PB3-PB5怎么处理

硬件片选和软件片选的区别
所谓硬件片选指的是SPI本身具有片选信号，当我们通过SPI发送数据时，SPI外设自动拉低CS信号使能从机，发送完成后自动拉高CS信号释放从机，这个过程是不需要软件操作的。而软件片选则是需要使用GPIO作为片选信号，SPI在发送数据之前，需要先通过软件设置作为片选信号的GPIO输出低电平，发送完成之后再设置该GPIO输出高电平。一般选择软件片选。

(5) 写W25QXX驱动代码

二、FRAM MB85RC16

(1) MB85RC16芯片引脚介绍

(2) 单片机如何读多块MB85RC16

即，当主机和一个EEPROM通信时，从机地址为1010 000+WR，如果主机和多个EEPROM通信时，从机地址为1010 A2 A1 A0 + WR

(3) IIC时序分析

a. 从机地址

b. 写单个字节

c. 写一页

一页的大小是8K,写入字节长度超过8K,将会覆盖之前写入内容

d. 当前地址读

e. 指定地址读

(4) STM32CubeMX配置IIC通信（HAL库）

标准模式，100KHz时钟，7位地址

(5) MB85RC16驱动代码

#define MB85RC16_Default_I2C_Addr 0xA0


void MB85RC16_Write(uint32_t addr, uint8_t * data, uint32_t len)
{
	uint8_t MB85RC16_I2C_Addr;

	MB85RC16_I2C_Addr = MB85RC16_Default_I2C_Addr | ((addr>>8)<<1); //high 3-bit access address placed into I2C address

	uint8_t TD[len+1];
	TD[0] = addr & 0x00FF;  //low 8-bit access address placed into I2C first data

	memcpy(TD+1, data, len);
	HAL_I2C_Master_Transmit(&hi2c1, MB85RC16_I2C_Addr, TD, len+1, 2700);  //Write data
}

void MB85RC1M_Read(uint32_t addr, uint8_t * data, uint32_t len)
{
	uint8_t MB85RC16_I2C_Addr;

	MB85RC16_I2C_Addr = MB85RC16_Default_I2C_Addr | ((addr>>8)<<1); //high 3-bit access address placed into I2C address

	uint8_t RA[1];
	RA[0] = addr & 0x00FF;  //low 8-bit access address placed into I2C first data

	HAL_I2C_Master_Transmit(&hi2c1, MB85RC16_I2C_Addr, &RA[0], 1, 2700); //Write address for read
	HAL_I2C_Master_Receive(&hi2c1, MB85RC16_I2C_Addr, data, len, 2700); //Read data

}

三、AT24CXX

(1)引脚介绍

A0,A1,A2接到GND上，地址固定为0；SCL、SDA引脚内部为开漏输出，所以需接上拉电阻；WP引脚接GND，表示芯片可读可写。

(2) GD32F470使用IIC读写AT24C02

iic.h

#ifndef __IIC_H
#define __IIC_H

#include "head.h"

#define I2C1_SPEED              400000
#define I2C1_SLAVE_ADDRESS7     0xA0
#define I2C_PAGE_SIZE           8

void i2c1_config(void);

#endif

iic.c

#include "iic.h"

void i2c1_config(void)
{
    rcu_periph_clock_enable(RCU_GPIOF);/* enable GPIOF clock */
    rcu_periph_clock_enable(RCU_I2C1);/* enable I2C1 clock */

    gpio_af_set(GPIOF, GPIO_AF_4, GPIO_PIN_1);/* connect PF1 to I2C1_SCL */
    gpio_af_set(GPIOF, GPIO_AF_4, GPIO_PIN_0);/* connect PF0 to I2C1_SDA */
    gpio_mode_set(GPIOF, GPIO_MODE_AF, GPIO_PUPD_PULLUP,GPIO_PIN_0);
    gpio_output_options_set(GPIOF, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ,GPIO_PIN_0);
    gpio_mode_set(GPIOF, GPIO_MODE_AF, GPIO_PUPD_PULLUP,GPIO_PIN_1);
    gpio_output_options_set(GPIOF, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ,GPIO_PIN_1);
	
    gpio_mode_set(GPIOF, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE,GPIO_PIN_2);
    gpio_output_options_set(GPIOF, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ,GPIO_PIN_2);
	gpio_bit_write(GPIOF,GPIO_PIN_2,RESET);//写使能
	
    rcu_periph_clock_enable(RCU_I2C1);/* enable I2C clock */
    i2c_clock_config(I2C1,I2C1_SPEED,I2C_DTCY_2);/* configure I2C clock */
    i2c_mode_addr_config(I2C1,I2C_I2CMODE_ENABLE,I2C_ADDFORMAT_7BITS,I2C1_SLAVE_ADDRESS7);/* configure I2C address */
    
    i2c_enable(I2C1);/* enable I2C1 */
    i2c_ack_config(I2C1,I2C_ACK_ENABLE);/* enable acknowledge */
}

eeprom.h

#ifndef __EEPROM_H
#define __EEPROM_H

#include "head.h"

#define EEP_FIRST_PAGE 0x00
#define I2C_OK         0
#define I2C_FAIL       1

/* I2C read and write functions */
uint8_t i2c_24c02_test(void);
/* initialize peripherals used by the I2C EEPROM driver */
void i2c_eeprom_init(void);
/* write buffer of data to the I2C EEPROM */
void eeprom_buffer_write(uint8_t *p_buffer, uint8_t write_address, uint16_t number_of_byte);
/* write one byte to the I2C EEPROM */
void eeprom_byte_write(uint8_t *p_buffer, uint8_t write_address);
/* write more than one byte to the EEPROM with a single write cycle */
void eeprom_page_write(uint8_t *p_buffer, uint8_t write_address, uint8_t number_of_byte);
/*  read data from the EEPROM */
void eeprom_buffer_read(uint8_t *p_buffer, uint8_t read_address, uint16_t number_of_byte);
/* wait for EEPROM standby state */
void eeprom_wait_standby_state(void);

#endif

eeprom.c

#include "eeprom.h"
#define EEPROM_BLOCK0_ADDRESS    0xA0
#define BUFFER_SIZE              256
uint16_t eeprom_address;

/*!
    \brief      I2C read and write functions
    \param[in]  none
    \param[out] none
    \retval     I2C_OK or I2C_FAIL 
*/
uint8_t i2c_24c02_test(void)
{
    uint16_t i;
    uint8_t i2c_buffer_write[BUFFER_SIZE];
    uint8_t i2c_buffer_read[BUFFER_SIZE];
    
    for(i = 0;i < BUFFER_SIZE;i++){ i2c_buffer_write[i]=i;}
    eeprom_buffer_write(i2c_buffer_write,EEP_FIRST_PAGE, BUFFER_SIZE); 

    eeprom_buffer_read(i2c_buffer_read,EEP_FIRST_PAGE, BUFFER_SIZE); 
    for(i = 0;i < BUFFER_SIZE;i++){printf("0x%02X ", i2c_buffer_read[i]);}
	
    return I2C_OK;
}
void i2c_eeprom_init(void)
{
    eeprom_address = EEPROM_BLOCK0_ADDRESS;
}

void eeprom_buffer_write(uint8_t* p_buffer, uint8_t write_address, uint16_t number_of_byte)
{
    uint8_t number_of_page = 0, number_of_single = 0, address = 0, count = 0;
    
    address = write_address % I2C_PAGE_SIZE;
    count = I2C_PAGE_SIZE - address;
    number_of_page =  number_of_byte / I2C_PAGE_SIZE;
    number_of_single = number_of_byte % I2C_PAGE_SIZE;
    
    /* if write_address is I2C_PAGE_SIZE aligned  */
    if(0 == address){
        while(number_of_page--){
            eeprom_page_write(p_buffer, write_address, I2C_PAGE_SIZE); 
            eeprom_wait_standby_state();
            write_address +=  I2C_PAGE_SIZE;
            p_buffer += I2C_PAGE_SIZE;
        }
        if(0 != number_of_single){
            eeprom_page_write(p_buffer, write_address, number_of_single);
            eeprom_wait_standby_state();
        }      
    }else{
       /* if write_address is not I2C_PAGE_SIZE aligned */
        if(number_of_byte < count){ 
            eeprom_page_write(p_buffer, write_address, number_of_byte);
            eeprom_wait_standby_state();
        }else{
            number_of_byte -= count;
            number_of_page =  number_of_byte / I2C_PAGE_SIZE;
            number_of_single = number_of_byte % I2C_PAGE_SIZE;
            
            if(0 != count){
                eeprom_page_write(p_buffer, write_address, count);
                eeprom_wait_standby_state();
                write_address += count;
                p_buffer += count;
            } 
            /* write page */
            while(number_of_page--){
                eeprom_page_write(p_buffer, write_address, I2C_PAGE_SIZE);
                eeprom_wait_standby_state();
                write_address +=  I2C_PAGE_SIZE;
                p_buffer += I2C_PAGE_SIZE;
            }
            /* write single */
            if(0 != number_of_single){
                eeprom_page_write(p_buffer, write_address, number_of_single); 
                eeprom_wait_standby_state();
            }
        }
    }  
}

void eeprom_byte_write(uint8_t* p_buffer, uint8_t write_address)
{
    /* wait until I2C bus is idle */
    while(i2c_flag_get(I2C1, I2C_FLAG_I2CBSY));

    /* send a start condition to I2C bus */
    i2c_start_on_bus(I2C1);
    
    /* wait until SBSEND bit is set */
    while(!i2c_flag_get(I2C1, I2C_FLAG_SBSEND));
    
	/* send slave address to I2C bus */
    i2c_master_addressing(I2C1, eeprom_address, I2C_TRANSMITTER);
    while(!i2c_flag_get(I2C1, I2C_FLAG_ADDSEND));
    
    /* clear the ADDSEND bit */
    i2c_flag_clear(I2C1,I2C_FLAG_ADDSEND);
    
    /* wait until the transmit data buffer is empty */
    while(SET != i2c_flag_get(I2C1, I2C_FLAG_TBE));
    
    /* send the EEPROM's internal address to write to : only one byte address */
	i2c_data_transmit(I2C1, 0x00);
    while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
    i2c_data_transmit(I2C1, write_address);
    while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
   
    /* send the byte to be written */
    i2c_data_transmit(I2C1, *p_buffer); 
    
    /* wait until BTC bit is set */
    while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));

    /* send a stop condition to I2C bus */
    i2c_stop_on_bus(I2C1);
    
    /* wait until the stop condition is finished */
    while(I2C_CTL0(I2C1)&I2C_CTL0_STOP);
}

void eeprom_page_write(uint8_t* p_buffer, uint8_t write_address, uint8_t number_of_byte)
{
    /* wait until I2C bus is idle */
    while(i2c_flag_get(I2C1, I2C_FLAG_I2CBSY));
    
    /* send a start condition to I2C bus */
    i2c_start_on_bus(I2C1);
    
    /* wait until SBSEND bit is set */
    while(!i2c_flag_get(I2C1, I2C_FLAG_SBSEND));
    
	/* send slave address to I2C bus */
    i2c_master_addressing(I2C1, eeprom_address, I2C_TRANSMITTER);
    while(!i2c_flag_get(I2C1, I2C_FLAG_ADDSEND));
    
    /* clear the ADDSEND bit */
    i2c_flag_clear(I2C1,I2C_FLAG_ADDSEND);
    
    /* wait until the transmit data buffer is empty */
    while( SET != i2c_flag_get(I2C1, I2C_FLAG_TBE));
    /* send the EEPROM's internal address to write to : only one byte address */
	i2c_data_transmit(I2C1, 0x00);
    while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
    i2c_data_transmit(I2C1, write_address);
    while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
    
    /* while there is data to be written */
    while(number_of_byte--){  
        i2c_data_transmit(I2C1, *p_buffer);
        
        /* point to the next byte to be written */
        p_buffer++; 
        
        /* wait until BTC bit is set */
        while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
    }
    /* send a stop condition to I2C bus */
    i2c_stop_on_bus(I2C1);
    
    /* wait until the stop condition is finished */
    while(I2C_CTL0(I2C1)&I2C_CTL0_STOP);
}

void eeprom_buffer_read(uint8_t* p_buffer, uint8_t read_address, uint16_t number_of_byte)
{  
    /* wait until I2C bus is idle */
    while(i2c_flag_get(I2C1, I2C_FLAG_I2CBSY));

    if(2 == number_of_byte){
        i2c_ackpos_config(I2C1,I2C_ACKPOS_NEXT);
    }
    
    /* send a start condition to I2C bus */
    i2c_start_on_bus(I2C1);
    
    /* wait until SBSEND bit is set */
    while(!i2c_flag_get(I2C1, I2C_FLAG_SBSEND));
    
	/* send slave address to I2C bus */
    i2c_master_addressing(I2C1, eeprom_address, I2C_TRANSMITTER);
    while(!i2c_flag_get(I2C1, I2C_FLAG_ADDSEND));
    
    /* clear the ADDSEND bit */
    i2c_flag_clear(I2C1,I2C_FLAG_ADDSEND);
    
    /* wait until the transmit data buffer is empty */
    while(SET != i2c_flag_get( I2C1 , I2C_FLAG_TBE));

    /* enable I2C1*/
    i2c_enable(I2C1);
    
    /* send the EEPROM's internal address to write to */
	i2c_data_transmit(I2C1, 0x00);  
    while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
    i2c_data_transmit(I2C1, read_address);  
    while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
    
    /* send a start condition to I2C bus */
    i2c_start_on_bus(I2C1);
    
    /* wait until SBSEND bit is set */
    while(!i2c_flag_get(I2C1, I2C_FLAG_SBSEND));
    
    /* send slave address to I2C bus */
    i2c_master_addressing(I2C1, eeprom_address, I2C_RECEIVER);

    if(number_of_byte < 3){
        /* disable acknowledge */
        i2c_ack_config(I2C1,I2C_ACK_DISABLE);
    }
    /* wait until ADDSEND bit is set */
    while(!i2c_flag_get(I2C1, I2C_FLAG_ADDSEND));
    
    /* clear the ADDSEND bit */
    i2c_flag_clear(I2C1,I2C_FLAG_ADDSEND);
    
    if(1 == number_of_byte){
        /* send a stop condition to I2C bus */
        i2c_stop_on_bus(I2C1);
    }
    
    /* while there is data to be read */
    while(number_of_byte){
        if(3 == number_of_byte){
            /* wait until BTC bit is set */
            while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));

            /* disable acknowledge */
            i2c_ack_config(I2C1,I2C_ACK_DISABLE);
        }
        if(2 == number_of_byte){
            /* wait until BTC bit is set */
            while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
            
            /* send a stop condition to I2C bus */
            i2c_stop_on_bus(I2C1);
        }
       /* wait until the RBNE bit is set and clear it */
        if(i2c_flag_get(I2C1, I2C_FLAG_RBNE)){
            /* read a byte from the EEPROM */
            *p_buffer = i2c_data_receive(I2C1);
            
            /* point to the next location where the byte read will be saved */
            p_buffer++; 
            
            /* decrement the read bytes counter */
            number_of_byte--;
        } 
    }
    
    /* wait until the stop condition is finished */
    while(I2C_CTL0(I2C1)&I2C_CTL0_STOP);
    /* enable acknowledge */
    i2c_ack_config(I2C1,I2C_ACK_ENABLE);

    i2c_ackpos_config(I2C1,I2C_ACKPOS_CURRENT);
}

void eeprom_wait_standby_state(void)
{
    __IO uint32_t val = 0;
    
    while(1){
        /* wait until I2C bus is idle */
        while(i2c_flag_get(I2C1, I2C_FLAG_I2CBSY));
        
        /* send a start condition to I2C bus */
        i2c_start_on_bus(I2C1);
        
        /* wait until SBSEND bit is set */
        while(!i2c_flag_get(I2C1, I2C_FLAG_SBSEND));
        
        /* send slave address to I2C bus */
        i2c_master_addressing(I2C1, eeprom_address, I2C_TRANSMITTER);
        
        /* keep looping till the Address is acknowledged or the AE flag is set (address not acknowledged at time) */
        do{
            /* get the current value of the I2C_STAT0 register */
            val = I2C_STAT0(I2C1);
            
        }while(0 == (val & (I2C_STAT0_ADDSEND | I2C_STAT0_AERR)));
        /* check if the ADDSEND flag has been set */
        if(val & I2C_STAT0_ADDSEND){
            
            /* clear ADDSEND flag */
            i2c_flag_clear(I2C1,I2C_FLAG_ADDSEND);
            
            /* send a stop condition to I2C bus */
            i2c_stop_on_bus(I2C1);
            
            /* exit the function */
            return ;
        } else {
            /* clear the bit of AERR */
            i2c_flag_clear(I2C1, I2C_FLAG_AERR);
        }
        
        /* send a stop condition to I2C bus */
        i2c_stop_on_bus(I2C1);
        /* wait until the stop condition is finished */
        while(I2C_CTL0(I2C1)&I2C_CTL0_STOP);
    }
}

四、总结

EEPROM和FLASH区别

相同点：

非易失性：两者都可以在没有电源的情况下保存数据。
电可擦除：都可以通过电信号擦除和重新编程。
用途：两者都用于存储固件、配置数据等。

不同点：

擦除单位：
- EEPROM：可以逐个字节擦除和写入。
- Flash：通常以块（通常是数KB到数MB）的方式擦除，不能逐个字节擦除。
写入速度：
- EEPROM：写入速度相对较慢，通常是字节级写入。
- Flash：写入速度较快，可以在一个块中并行写入。
使用寿命：
- EEPROM：通常具有更高的擦写耐久性，通常为10万次擦写。
- Flash：擦写次数一般较少，通常为1万到10万次，但近年来的发展使得一些Flash类型的耐久性有所提高。
成本和密度：
- EEPROM：相对较贵，存储密度较低。
- Flash：更便宜，存储密度更高，因此在大容量存储解决方案中更受欢迎。
应用场景：
- EEPROM：常用于需要频繁更新的小规模数据，典型应用包括配置存储、校准数据等。
- Flash：被广泛用于USB闪存驱动器、SD卡、固态硬盘（SSD）等大容量存储设备。