前言:这个问题与我正在与大学教授合作的项目有关。这不是为了成绩，而是我在这位教授中的声誉确实很重要。因此，尽管我在该项目上的成功对我很重要，但我并不认为从Stack Overflow寻求帮助是不公平的。
就是说，这是我的项目的高级概述。我有一个ATmega328微 Controller 。我有一个Microchip SST 64 Mbit闪存卡。 ATmega具有SPI的硬件实现。闪存具有SPI的硬件实现。
我的目标是在SPI主模式下使用ATmega从闪存芯片读取数据并将数据写入闪存芯片。存储器以多重覆盖结构组织，可以很好地擦除，但出于我的目的，它基本上只有32,768页，每页256个字节。
写数据的基本思想是我发送一个指令字节，然后是起始地址，然后是数据。要读取数据，基本思想是我先发送一个指令字节，然后是起始地址，然后是一个虚拟字节，然后它开始向我发送数据。
这是数据表:
单片机:http://www.atmel.com/dyn/resources/prod_documents/doc8271.pdf
Flash:http://www.sst.com/dotAsset/40498.pdf
代码:#include <SPI.h>
#include <Peggy2.h>
#define SS_PIN 16
Peggy2 frame1;
byte toDisp = 0;
byte checker = 0;
void setup()
{
frame1.HardwareInit();
pinMode(SS_PIN,OUTPUT); //set pin16 to output, SS pin
SPI.setClockDivider(SPI_CLOCK_DIV2); //set the SPI clock to f/2, fastest possible
SPI.begin(); //SPI lib function which sets ddr for SCK and MOSI pin
//MISO is auto input
//see SPI.cpp for more info
}
void loop()
{
if(!checker){
enableProgramming();
programData();
toDisp = receiveByte(0);
checker = 1;
frame1.WriteRow(0,toDisp);
}
frame1.RefreshAll(2);
}
byte receiveByte(unsigned long startAddress)
{
//Begin High Speed Read Instruction
//See p. 10 of SST data sheet
digitalWrite(SS_PIN,LOW);
SPI.transfer(0x0B); //high speed read instruction
SPI.transfer(0x00); //next 3 transfers are address bits A32 - A0
SPI.transfer(0x00); //So this will read the first byte on the chip
SPI.transfer(0x00); //last address bits
SPI.transfer(0xFF); //dummy byte is required to start sending data back to uP
SPI.transfer(0xFF); //I'm hoping that if I transfer a bullshit byte, the flash
//chip will transfer it's data to me in the same time
digitalWrite(SS_PIN,HIGH);
//End High Speed Read Instruction
return SPDR;
}
//will perform the read instruction starting from
//startAddress and will receive numOfBytes bytes in
//succession
void receiveBytes(int numOfBytes, unsigned long startAddress)
{
digitalWrite(SS_PIN,LOW);
SPI.transfer(0x0B);//high speed read instruction
}
//will perform:
// 1) Chip Erase
// and loop through:
// 1) Page Program
// 2) increment Page
//until the data has finished **note this can loop and over write beginning of memory
void programData(){
//Begin ChipErase Instruction
//See p. 17 of SST data sheet
digitalWrite(SS_PIN,LOW);
SPI.transfer(0x60);//chip erase instruction
digitalWrite(SS_PIN,HIGH);
delay(50);//spec'd time for CE to finish
//don't bother polling because time to program is irrelevant
//End ChipErase Instruction
//Begin WREN Instruction
//See p. 18 of SST data sheet
digitalWrite(SS_PIN,LOW);
SPI.transfer(0x06);//write enable instruction
digitalWrite(SS_PIN,HIGH);
//End WREN Instruction
digitalWrite(SS_PIN,LOW);
SPI.transfer(0x02); //page program instruction
SPI.transfer(0x00); //first 8 address bits
SPI.transfer(0x00); //2nd 8 address bits
SPI.transfer(0x00); //3rd 8 address bits
SPI.transfer(0xAA); //10101010 is the byte I should be writing
digitalWrite(SS_PIN,HIGH);
delayMicroseconds(3000); //wait 3 ms for page program
/*
//Begin Page-Program Instruction
//see p. 13 of SST data sheet
byte firstAddress = 0;
byte secondAddress = 0;
//this loop will write to every byte in the chips memory
//32,768 pages of 256 bytes = 8,388,608 bytes
for(unsigned int i = 0; i < 32,768; ++i) //long variable is number of pages
{
digitalWrite(SS_PIN,LOW);
++secondAddress; //cycles from 0 to 255, counts pages
firstAddress = i>>8; // floor(i/256)
SPI.transfer(0x02);//Page-Program instruction byte
SPI.transfer(firstAddress); //increments every 256 pages i.e. at page 256 this should be 1
SPI.transfer(secondAddress); //increments every 256 bytes, i.e every page
SPI.transfer(0x00); //beginning of a page boundary
for(int j = 0; j < 256; ++j) //number of bytes per page
{
SPI.transfer(2program[(256*i) + j]);//data byte transfer
}
digitalWrite(SS_PIN,HIGH);
delayMicroseconds(2500); //2500us (2.5ms) delay for each page-program instruction to execute
}
//End Page-Program Instruction
*/
}
//Will prepare the chip for writing by performing:
// 1) arm the status register
// 2) Write Enable instruction
//Only needs to be performed once!
void enableProgramming(){
//Begin EWSR & WRSR Instructions
//See p. 20 of SST data sheet for more info
digitalWrite(SS_PIN,LOW); //lower the SS pin
SPI.transfer(0x50); //enable write status register instruction
digitalWrite(SS_PIN,HIGH); //raise the SS pin
delay(10);
digitalWrite(SS_PIN,LOW); //lower the SS pin
SPI.transfer(0x01); //write the status register instruction
SPI.transfer(0x00);//value to write to register
//xx0000xx will remove all block protection
digitalWrite(SS_PIN,HIGH);
//End EWSR & WRSR Instructions
//Begin WREN Instruction
//See p. 18 of SST data sheet
digitalWrite(SS_PIN,LOW);
SPI.transfer(0x06);//write enable instruction
digitalWrite(SS_PIN,HIGH);
//End WREN Instruction
}
因此，这应该是一个测试程序，该程序将1个字节写入闪存，然后将其读回并在我拥有的LED阵列上显示该字节。如果您对LED阵列感兴趣，可以在这里找到:http://evilmadscience.com/tinykitlist/157
我相信我的读取功能有效，因为我第一次运行此功能时，所有8个LED均亮起。这将向我表明，当它处于全1的出厂状态时，它将读取闪存。现在，显然我已经弄错了写作内容，因为点亮的字节与我尝试编程的字节根本不对应。
我还应该注意，我正在为Arduino使用默认的SPI库，并且帧缓冲功能正常工作。当我执行frame1.WriteRow(toDisp)时，它可以正常工作，并且已经过广泛测试。
如果有人有时间或耐心找出我在做什么错，那将是非常棒的事情。
编辑:为了帮助调试:
LED也由使用SPI接口(interface)的驱动器芯片驱动。我没有写那部分代码。在示波器上，我可以看到SCK线由该部分代码驱动。但是，我在MOSI引脚上也有一个探头，如果我不点亮任何灯，则它永远不会变高。对我来说，这意味着我没有正确发送信息。又名...也许我的SPI.transfer()需要启用功能或其他功能？
最佳答案
对于仍然感到好奇的人来说，问题在于存储芯片对缓慢的上升时间极为敏感。放入施密特触发器后，一切运行正常。
关于arduino - ATmega328 + SPI闪存，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/3980939/