PIC16F18325 EEPROM不可靠的回读失败

您的代码在启动后是否尝试写入EEPROM？你的电源延迟激活了吗？是否启用了棕色输出复位功能？如果你开始写作，而权力仍然稳定，你会得到坏的结果。



      以下为原文

    Is your code attempting to write to EEPROM as soon as it starts?
Do you have the power up delay activated?
Do you have Brown Out reset enabled?
 
If you start writing while the power is still stabilising, you will get bad results.
 

你的函数等待写标志完成吗？芯片是否在规定的电压范围内运行？有合适的帽子吗？一个稳定的电源？



      以下为原文

    Do you functions wait for the write flag to finish? Is the chip running within the specified voltage? With the proper caps? And a stable power supply?

如果这些函数不起作用，唯一的选择是访问硬件寄存器并自己滚动。检查数据表。第11.3至11.4节



      以下为原文

    If those functions do not work, the only option is to access the hardware registers and roll your own.
 
Check the datasheet.  Section 11.3 - 11.4

谢谢大家的回复。我已经编写了一些测试代码来测试控制器EEPROM最基本的功能：写一个值到EEPROM的第一个地址，然后读取它。它试图遵循产品数据表中规定的指导方针。这里是代码：（所有的NOP（）不改变任何东西，我得到相同的结果有或没有它们）。当我在调试器中运行这个代码时，读回的值，即NVMDTAL的值，似乎总是255＝0xFF，不管我写什么给EEPROM。我将任意值放入NVMDTL中，看看它们是否因为读取操作而改变，并且值总是变为255。控制器是PIC16F18326。有人会指出我在写EEPROM的过程中漏掉的东西，然后读取它的值吗？有初始化程序吗？



      以下为原文

    Thanks all for your replies.
 
I have written some test code to test the most basic functionality of the controller EEPROM: write a value to the first address of the EEPROM and read it back. It tries to follow the guidelines as specified in the product datasheet. Here is the code:
 char dataval = 0;

void main(void)
{
    // initialize the device
    SYSTEM_Initialize();
    _delay( 1000 );
   
    NVMCON1bits.NVMREGS = 1; // Configuarion Select bit, 1 = Access EEPROM
    NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();
    
    NVMDATL = 0x02;
    
    NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();
    NVMADRH = 0x70;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMADRL = 0x00;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMCON1bits.RD = 1;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    dataval = NVMDATL;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMCON1bits.WREN = 1; // Program/Erase enable bit, 1 = Allows program/erase cycle
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();


    NVMDATL = 0x78;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    // Unlock routine:
    INTCONbits.GIE = 0;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMCON2 = 0x55;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMCON2 = 0xAA;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMCON1bits.WR = 1;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    INTCONbits.GIE = 1;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    while ( NVMCON1bits.WR )
        ;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMDATL = 0x02;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMCON1bits.RD = 1;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    dataval = NVMDATL;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    dataval = 0x87;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();
 
    NVMCON1bits.WREN = 1; // Program/Erase enable bit, 1 = Allows program/erase cycle
     NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMDATL = 0x3C;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    INTCONbits.GIE = 0;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMCON2 = 0x55;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMCON2 = 0xAA;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMCON1bits.WR = 1;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    INTCONbits.GIE = 1;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    while ( NVMCON1bits.WR )
        ;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMDATL = 0x1A;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    NVMCON1bits.RD = 1;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    dataval = NVMDATL;
        NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();NOP();

    while (1)
    {

    }
}
/**
 End of File
*/
 
(All the NOP()'s do not change anything, I got the same results with or without them).
When I run this code in the debugger, the value read back, which is the value of NVMDATL, seems to always be 255 = 0xFF, no matter what I write to EEPROM. I'm putting arbitrary values into NVMDATL to see if they change as a result of a read operation, and the values always change to 255.
 
The controller is PIC16F18326. Can someone point to something I missed in the procedure to write to EEPROM and read the value back? Is there an initialization procedure?

解锁序列中不能有NOP，写入NVM将无法与它们一起工作。如果EEPROM代码保护开启，则无法读取/写入EEPROM。检查一下。我不能，因为你没有张贴配置。检查程序清单或程序内存（代码模式）的解锁序列，并确保编译器没有做什么有趣的。不太可能，但我想是可能的。



      以下为原文

    The unlock sequence can't have NOPs in it and writes to NVM will not work with them.
You can't read/write EEPROM if EEPROM code protection is on. Check that. I can't since you haven't posted the configuration.
Check the assembly listing or program memory (code mode) for the unlock sequence and ensure the compiler isn't doing something funny there. Not likely but possible I suppose.
 

非常感谢你的回复，结果是硬件问题。我们所拥有的整个系列控制器（和我们订购的类似的测试设备）显然有故障的EEPROM。未能正常写入和读取EEPROM的代码，成功地使用了我们拥有的不同控制器家族。不是完全兼容PIN，但对我们的项目来说是足够好的。然而，有价值的信息在那里。谢谢。



      以下为原文

     
mbrowning
Thanks very much for the reply, it turns out it was a hardware issue. The entire series of controllers we had (and similar ones we ordered for testing) apparently had malfunctioning EEPROMs. The code which failed to write to and read from EEPROM properly, succeeded with a different family of controllers we had. Not entirely pin compatible, but good enough for our project.
 
Nevertheless, valuable information there. Thanks.