廉价SD卡模块Arduino无法初始化解决办法
试了很多次，无法初始化SD卡，开始以为电源不够，也采用单独供电试过。后来翻看资料增加电平转换OK。
上图中使用SD和Arduino连接部分即可
/*
SD card datalogger
This example shows how to log data from three analog sensors
to an SD card using the SD library.
The circuit:
* SD card attached to SPI bus as follows:
** UNO:MOSI - pin 11, MISO - pin 12, CLK - pin 13, CS - pin 4 (CS pin can be changed)
and pin #10 (SS) must be an output
** Mega:MOSI - pin 51, MISO - pin 50, CLK - pin 52, CS - pin 4 (CS pin can be changed)
and pin #52 (SS) must be an output
** Leonardo: Connect to hardware SPI via the ICSP header
Pin 4 used here for consistency with other Arduino examples
created24 Nov 2010
modified 9 Apr 2012 by Tom Igoe
This example code is in the public domain.
*/
#include <SPI.h>
#include <SD.h>
// On the Ethernet Shield, CS is pin 4. Note that even if it's not
// used as the CS pin, the hardware CS pin (10 on most Arduino boards,
// 53 on the Mega) must be left as an output or the SD library
// functions will not work.
const int chipSelect = 53;
File dataFile;
void setup()
{
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only
}
Serial.print("Initializing SD card...");
// make sure that the default chip select pin is set to
// output, even if you don't use it:
pinMode(SS, OUTPUT);
// see if the card is present and can be initialized:
if (!SD.begin(chipSelect)) {
Serial.println("Card failed, or not present");
// don't do anything more:
while (1) ;
}
Serial.println("card initialized.");
// Open up the file we're going to log to!
dataFile = SD.open("datalog.txt", FILE_WRITE);
if (! dataFile) {
Serial.println("error opening datalog.txt");
// Wait forever since we cant write data
while (1) ;
}
}
void loop()
{
// make a string for assembling the data to log:
String dataString = "";
// read three sensors and append to the string:
for (int analogPin = 0; analogPin < 3; analogPin++) {
int sensor = analogRead(analogPin);
dataString += String(sensor);
if (analogPin < 2) {
dataString += ",";
}
}
dataFile.println(dataString);
// print to the serial port too:
Serial.println(dataString);
// The following line will 'save' the file to the SD card after every
// line of data - this will use more power and slow down how much data
// you can read but it's safer!
// If you want to speed up the system, remove the call to flush() and it
// will save the file only every 512 bytes - every time a sector on the
// SD card is filled with data.
dataFile.flush();
// Take 1 measurement every 500 milliseconds
delay(500);
}
上面这个模块在国外很出名啊，老外觉得灰常便宜还从香港包邮
稳压管采用3.3V的
去掉电容测试，也能初始化
电容、电阻去掉后SD卡还是能初始化 MD毛线，去掉电容、电阻，稳压管直接连接，现在居然也行了。。。:L:L:L:L:L:L:L
接稳压管之前用IDE自带例子，不是发的这个，难道程序问题？！ 面包板有时插得不好，接触不好或电阻大，就有问题。原来我调IIC时也时，明明电路对，就是不读，后来全重插一遍，就又好了。 增加电平转换是什么意思？
前几天我也在搞这个，一个SD卡死活不认，另外一个没问题
本帖最后由 wwwusr 于 2015-2-28 10:43 编辑
http://hackerspace-ffm.de/wiki/index.php?title=SimpleSDAudio
http://www.geek-workshop.com/thread-2611-1-1.html
这个例子里有SD卡的连接方法，应该是SD卡的电压是3.3V,如果你的arduino是5V版本的，那么，与SD卡之间的电压 通信，都要有电平转换。
不然就会通信不上，卡烫手，最后卡挂掉。
直接3.3v供电，稳定着呢 5v系统电平转换，是必须的。 zoologist 发表于 2015-2-28 09:32 static/image/common/back.gif
增加电平转换是什么意思？
前几天我也在搞这个，一个SD卡死活不认，另外一个没问题
针对这个模块，如果是51单片机，需将5Vcmos点平转成3.3V TTL电平 dataFile.flush();
没在SD library看到这个函数，是什么意思？
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