PIC18F2520 mplab x xc8 EEPROM

Question

Platform MPLAB X
CPU PIC18F2520
Compiler XC8 v1.38

我们正在将一个项目从旧的(htc(编译器转移到MPLAB X平台，但无法访问EEPROM。

旧的编译器支持eeprom_read和eeprom_write，但支持XC8没有，好吧，有定义它们，但它们是"空的"。(xc.h包括htc.h，htc.h包括pic18.h(图h中线

#if _EEPROMSIZE > 0 && defined(_PLIB)

不是触发的，而是相应的#else似乎既没有定义_EEPROMSIZE，也没有定义_PLIB。

为什么老的(eeprom_read和eeprom_write(xc8中不支持？

我们应该做些什么才能访问EEPROM？

我们试着看看Microchip Code Configure会做些什么，但是MCC不支持CPU PIC18F2520。

The chip do have 256 byte eeprom according to

http://ww1.microchip.com/downloads/en/DeviceDoc/39631E.pdf

问候

Answer 1

是的，正如您所发现的，Microchip已经删除了MPLAB X IDE中PIC18系列微控制器的EEPROM读/写功能。它将宏保留为空壳(EEPROM_READ()、eeprom_read()、e.t.c(，不会抛出编译器错误/警告，但实际上不会执行任何操作！

pic18.h建议，如果#if _EEPROMSIZE > 0 && defined(_PLIB)为真，则宏将被填充，但通过手动添加PLIB宏定义，编译器随后抱怨找不到plib.h。我找不到合适的地方下载"plib"。

一个选项是恢复到直接寄存器操作以执行EEPROM读/写(请参见第75页http://ww1.microchip.com/downloads/en/DeviceDoc/39626e.pdf用于一个特定PIC18微的EEPROM寄存器定义(。我写了以下函数，这些函数将其抽象出来，并提供与Microchip移除的功能类似的功能：

//! @brief      Reads a single byte of data from the EEPROM.
//! @param      address     The EEPROM address to write the data to (note that not all
//!                         16-bits of this variable may be supported).
//! @returns    The byte of data read from EEPROM.
//! @warning    This function does not return until read operation is complete.
uint8_t Eeprom_ReadByte(uint16_t address)
{
    // Set address registers
    EEADRH = (uint8_t)(address >> 8);
    EEADR = (uint8_t)address;
    EECON1bits.EEPGD = 0;       // Select EEPROM Data Memory
    EECON1bits.CFGS = 0;        // Access flash/EEPROM NOT config. registers
    EECON1bits.RD = 1;          // Start a read cycle
    // A read should only take one cycle, and then the hardware will clear
    // the RD bit
    while(EECON1bits.RD == 1);
    return EEDATA;              // Return data
}
//! @brief      Writes a single byte of data to the EEPROM.
//! @param      address     The EEPROM address to write the data to (note that not all
//!                         16-bits of this variable may be supported).
//! @param      data        The data to write to EEPROM.
//! @warning    This function does not return until write operation is complete.
void Eeprom_WriteByte(uint16_t address, uint8_t data)
{    
    // Set address registers
    EEADRH = (uint8_t)(address >> 8);
    EEADR = (uint8_t)address;
    EEDATA = data;          // Write data we want to write to SFR
    EECON1bits.EEPGD = 0;   // Select EEPROM data memory
    EECON1bits.CFGS = 0;    // Access flash/EEPROM NOT config. registers
    EECON1bits.WREN = 1;    // Enable writing of EEPROM (this is disabled again after the write completes)
    // The next three lines of code perform the required operations to
    // initiate a EEPROM write
    EECON2 = 0x55;          // Part of required sequence for write to internal EEPROM
    EECON2 = 0xAA;          // Part of required sequence for write to internal EEPROM
    EECON1bits.WR = 1;      // Part of required sequence for write to internal EEPROM
    // Loop until write operation is complete
    while(PIR2bits.EEIF == 0)
    {
        continue;   // Do nothing, are just waiting
    }
    PIR2bits.EEIF = 0;      //Clearing EEIF bit (this MUST be cleared in software after each write)
    EECON1bits.WREN = 0;    // Disable write (for safety, it is re-enabled next time a EEPROM write is performed)
}

Answer 2

使用MCC选择内存模块，它将创建具有所需所有功能的内存.c