Required parts and tools<\/h3>\n\n- An Arduino Uno or compatible board.<\/li>\n
- One micro SD card module. This is Siratek product 6573.<\/li>\n
- A micro SD card, 32 GB or smaller, formatted FAT32.<\/li>\n
- Six jumper wires.<\/li>\n<\/ul>\n
This module is safe on 5 V<\/h3>\n
Worth stating plainly, because the usual advice about small SD modules is that they are not.<\/p>\n
SD cards are 3.3 V devices and an Uno\u2019s pins swing to 5 V, so a bare socket wired straight to an Arduino will eventually damage the card. Many small modules do no conversion at all.<\/p>\n
This one does.<\/strong> The board carries a 74LVC125A<\/strong> buffer, which is the level shifter, and a three-pin regulator in a SOT-223 package to make 3.3 V for the card. Both are visible on the board: the buffer is the small chip marked LVC125A<\/code> beside the socket, the regulator the larger three-legged part with a metal tab.<\/p>\nSo connect VCC<\/code> to the Uno\u2019s 5V<\/code> pin. The regulator needs the higher voltage to work from; feed it 3.3 V instead and it has nothing to regulate.<\/p>\nIf you ever use a different module, look for those two parts before trusting it with a card.<\/p>\n
Cards, and why one may simply not work<\/h3>\n
This is the most common frustration with SD on an Arduino, and it is usually the card rather than anything you did.<\/p>\n
\n- 32 GB or smaller.<\/strong> Larger cards are SDXC and formatted exFAT, which the standard library does not read. A 64 GB card reformatted as FAT32 often works, but a 32 GB card avoids the question.<\/li>\n
- FAT32, not exFAT or NTFS.<\/strong> Format it in the computer, and choose FAT32 explicitly.<\/li>\n
- Class 4 or 10, a known brand.<\/strong> Very cheap or counterfeit cards fail in ways that look like wiring faults, and they fail intermittently, which is worse.<\/li>\n<\/ul>\n
If a card refuses to initialise, try a different card before changing anything else. It resolves this more often than any other single step.<\/p>\n
Filenames must be 8.3<\/h3>\n
The library uses short DOS-style names: up to eight characters, a dot, up to three more<\/strong>. LOG.CSV<\/code> and DATA0001.TXT<\/code> are fine. sensor-readings.csv<\/code> is not, and the failure is silent: the file is simply never created, and every write succeeds into nothing.<\/p>\nCase is not preserved either. Use capitals and keep to the limit.<\/p>\n
The pins it takes, and what that costs<\/h3>\n
SPI needs four pins, and on an Uno they are fixed: D11<\/code>, D12<\/code> and D13<\/code> for data and clock, plus a chip select which can be any pin but conventionally is D10<\/code>.<\/p>\nThat means D10<\/code> to D13<\/code> are gone<\/strong>, and they are the same pins the MAX7219 tutorial used. Both can share the bus if each has its own chip select, but it is worth knowing before you plan a project around all three.<\/p>\nPower, which is the other common fault<\/h3>\n
A card can draw a surprising burst of current while writing, up to a hundred milliamps or so. On USB power with nothing else connected, that is fine. Alongside a display and a couple of sensors, it is the thing that makes a board reset mid-write.<\/p>\n
A reset mid-write is worse than it sounds, because it can leave the file system damaged rather than just losing a line. The defence is in the code below: open the file, write, close it, every time. A closed file is a safe file.<\/p>\n
Pin reference<\/h2>\n
\n\n\nModule pin<\/th>\n Connect to<\/th>\n Purpose<\/th>\n Notes<\/th>\n<\/tr>\n<\/thead>\n \n\nGND<\/code><\/td>\nUno GND<\/code><\/td>\nGround<\/td>\n <\/td>\n<\/tr>\n \nVCC<\/code><\/td>\nUno 5V<\/code><\/td>\nPower<\/td>\n The board makes its own 3.3 V<\/td>\n<\/tr>\n \nMISO<\/code><\/td>\nUno D12<\/code><\/td>\nData from the card<\/td>\n <\/td>\n<\/tr>\n \nMOSI<\/code><\/td>\nUno D11<\/code><\/td>\nData to the card<\/td>\n <\/td>\n<\/tr>\n \nSCK<\/code><\/td>\nUno D13<\/code><\/td>\nClock<\/td>\n <\/td>\n<\/tr>\n \nCS<\/code><\/td>\nUno D10<\/code><\/td>\nChip select<\/td>\n Any pin, but the library defaults near this<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n![\"A](\"http:\/\/siratek.net\/wp-content\/uploads\/2026\/11\/sd-card-logging-wiring.svg\")
This module has a level shifter and its own regulator, so VCC goes to 5V.<\/figcaption><\/figure>\nWiring steps<\/h2>\n\n- Unplug the USB cable.<\/li>\n
GND<\/code> to GND<\/code>, VCC<\/code> to 5V<\/code>.<\/li>\nMISO<\/code> to D12<\/code>, MOSI<\/code> to D11<\/code>, SCK<\/code> to D13<\/code>.<\/li>\nCS<\/code> to D10<\/code>.<\/li>\n- Insert a FAT32-formatted card, 32 GB or smaller.<\/li>\n
- Plug the USB cable back in.<\/li>\n<\/ol>\n
Keep these leads short. SPI at a few megahertz over long loose jumper wires is a real source of intermittent failures, and the symptom is a card that initialises sometimes.<\/p>\n
Software and libraries<\/h2>\n
SD<\/code> ships with the Arduino IDE. Nothing to install.<\/p>\nMinimal working example<\/h2>\n
Prove the card works before writing anything that matters.<\/p>\n
\/\/ Siratek: confirm the card initialises and list what is on it.\n\n#include <SPI.h>\n#include <SD.h>\n\nconst int chipSelect = 10;\n\nvoid setup() {\n Serial.begin(9600);\n while (!Serial) {\n ;\n }\n\n Serial.print(\"Siratek: starting the card... \");\n\n if (!SD.begin(chipSelect)) {\n Serial.println(\"failed.\");\n Serial.println(\" Check the card is FAT32 and 32 GB or smaller,\");\n Serial.println(\" check CS is on pin 10, and try another card.\");\n return;\n }\n\n Serial.println(\"ready.\");\n\n File root = SD.open(\"\/\");\n while (true) {\n File entry = root.openNextFile();\n if (!entry) {\n break;\n }\n Serial.print(\" \");\n Serial.print(entry.name());\n Serial.print(\" \");\n Serial.println(entry.size());\n entry.close();\n }\n root.close();\n}\n\nvoid loop() {\n}<\/code><\/pre>\nA blank card lists nothing, which is correct. What matters is \u201cready\u201d rather than \u201cfailed\u201d.<\/p>\n
Logging readings as CSV<\/h3>\n\/\/ Siratek: a temperature log with a real timestamp, one line per minute.\n\n#include <SPI.h>\n#include <SD.h>\n#include <Wire.h>\n#include <RTClib.h>\n\nconst int chipSelect = 10;\nconst char* filename = \"LOG.CSV\";\n\nRTC_DS3231 rtc;\n\nconst unsigned long interval = 60000UL;\nunsigned long lastWrite = 0;\n\nbool cardReady = false;\n\nvoid setup() {\n Serial.begin(9600);\n\n if (!rtc.begin()) {\n Serial.println(\"Siratek: no clock found.\");\n }\n\n cardReady = SD.begin(chipSelect);\n if (!cardReady) {\n Serial.println(\"Siratek: no card. Logging disabled, serial only.\");\n return;\n }\n\n \/\/ Write a header once, when the file is first created.\n if (!SD.exists(filename)) {\n File f = SD.open(filename, FILE_WRITE);\n if (f) {\n f.println(\"timestamp,temperature_c\");\n f.close();\n }\n }\n\n lastWrite = millis() - interval; \/\/ log once immediately\n}\n\nvoid logLine(const String& line) {\n Serial.println(line);\n\n if (!cardReady) {\n return;\n }\n\n \/\/ Open, write, close, every time. A closed file survives a power cut.\n File f = SD.open(filename, FILE_WRITE);\n if (f) {\n f.println(line);\n f.close();\n } else {\n Serial.println(\" could not open the file\");\n }\n}\n\nvoid loop() {\n if (millis() - lastWrite < interval) {\n return;\n }\n lastWrite = millis();\n\n DateTime now = rtc.now();\n float temperature = rtc.getTemperature();\n\n String line = String(now.year()) + \"-\" +\n String(now.month()) + \"-\" +\n String(now.day()) + \" \" +\n String(now.hour()) + \":\" +\n String(now.minute()) + \":\" +\n String(now.second()) + \",\" +\n String(temperature, 1);\n\n logLine(line);\n}<\/code><\/pre>\nFour decisions here are the difference between a logger and a disappointment.<\/p>\n
The file is opened and closed around every write.<\/strong> Holding it open is faster and loses everything buffered if power goes. For a reading a minute, the speed does not matter and the safety does.<\/p>\nThe sketch keeps working without a card.<\/strong> cardReady<\/code> means a missing card costs you the log, not the project. A logger that refuses to run because the card is out is worse than one that carries on and tells you.<\/p>\nThe header is written only when the file does not yet exist<\/strong>, so restarting the logger appends to the same file rather than scattering headers through it.<\/p>\nIt is CSV<\/strong>, which opens directly in any spreadsheet. One line per reading, commas between fields, no quotes needed for plain numbers.<\/p>\nUsing String, and when not to<\/h3>\n
The sketch above builds each line with String<\/code>, which is readable and fine at one line a minute.<\/p>\nString<\/code> allocates memory as it goes, and on a board with 2 KB of RAM, repeated allocation gradually fragments the heap. In a loop running many times a second, that ends in a sketch that runs for hours and then freezes.<\/p>\nIf you log frequently, build the line into a fixed char<\/code> buffer with snprintf()<\/code> instead. For a slow logger, leave it alone and spend the effort elsewhere.<\/p>\nExpected result<\/h2>\n
\u201cready\u201d on the serial monitor, a LOG.CSV<\/code> appearing on the card, and one line added per minute.<\/p>\nTake the card to a computer and open the file in a spreadsheet. The columns should separate automatically, and a chart of the temperature column is about three clicks away. That moment is the point of the whole tutorial.<\/p>\n
Troubleshooting<\/h2>\n
\n\n\nSymptom<\/th>\n Likely cause<\/th>\n Check or fix<\/th>\n<\/tr>\n<\/thead>\n \n\nInitialisation failed<\/td>\n Card too large or wrong format<\/td>\n 32 GB or smaller, FAT32<\/td>\n<\/tr>\n \nInitialisation failed, card fine<\/td>\n CS<\/code> on the wrong pin<\/td>\nMatch the pin in SD.begin()<\/code><\/td>\n<\/tr>\n\nFails intermittently<\/td>\n Long or loose jumper leads<\/td>\n Shorten and reseat them<\/td>\n<\/tr>\n \nFails with one card, works with another<\/td>\n Cheap or counterfeit card<\/td>\n Use a known brand<\/td>\n<\/tr>\n \nFile never appears<\/td>\n Filename longer than 8.3<\/td>\n LOG.CSV<\/code>, not sensor-log.csv<\/code><\/td>\n<\/tr>\n\nFile exists but is empty<\/td>\n Not closed before power was lost<\/td>\n Close after every write<\/td>\n<\/tr>\n \nBoard resets while writing<\/td>\n Current burst during a write<\/td>\n Check the power budget<\/td>\n<\/tr>\n \nCard corrupted after a reset<\/td>\n File open when power went<\/td>\n Open, write, close each time<\/td>\n<\/tr>\n \nWorks alone, not with a display<\/td>\n Both on SPI<\/td>\n Separate chip select pins<\/td>\n<\/tr>\n \nRuns for hours then freezes<\/td>\n String<\/code> fragmenting the heap<\/td>\nUse snprintf()<\/code> into a fixed buffer<\/td>\n<\/tr>\n\nTimestamps all identical<\/td>\n Clock not set<\/td>\n See Keeping Time with a DS3231<\/em><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\nNext steps<\/h2>\n\n- Easier first:<\/strong> Keeping Time with a DS3231<\/em>, which supplies the timestamp.<\/li>\n
- Related products:<\/strong> any sensor in this library; the DS18B20 and the DHT11 are the obvious first choices.<\/li>\n
- Next project:<\/strong> a standalone data logger, left running for a week, and the chart that comes out of it.<\/li>\n<\/ul>\n
Sources and attribution<\/h2>\n
All text, wiring guidance and code in this tutorial are original Siratek work.<\/p>\n
\n- The
74LVC125A<\/code> level shifter and the SOT-223 regulator on this module were read from the Siratek product photographs for item 6573, which is what establishes that the board is safe on a 5 V Arduino rather than 3.3 V only.<\/li>\n- Arduino
SD<\/code> library documentation for the 8.3 filename limit and the supported formats.<\/li>\n<\/ul>\nCard capacity and formatting limits are properties of the standard library rather than of this module. No third-party tutorial text, diagrams, photographs or code has been reproduced here.<\/p>\n
<\/p>\n<\/body>","protected":false},"excerpt":{"rendered":"
A micro SD card socket on a small board, so an Arduino can write files. Readings go to a card, the card goes into a computer, and you open the result in a spreadsheet.<\/p>\n","protected":false},"featured_media":0,"template":"","siratek_tutorial_level":[],"class_list":["post-52346","siratek_tutorial","type-siratek_tutorial","status-publish","hentry"],"yoast_head":"\n
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This module is safe on 5 V<\/h3>\n
Worth stating plainly, because the usual advice about small SD modules is that they are not.<\/p>\n
SD cards are 3.3 V devices and an Uno\u2019s pins swing to 5 V, so a bare socket wired straight to an Arduino will eventually damage the card. Many small modules do no conversion at all.<\/p>\n
This one does.<\/strong> The board carries a 74LVC125A<\/strong> buffer, which is the level shifter, and a three-pin regulator in a SOT-223 package to make 3.3 V for the card. Both are visible on the board: the buffer is the small chip marked So connect If you ever use a different module, look for those two parts before trusting it with a card.<\/p>\n This is the most common frustration with SD on an Arduino, and it is usually the card rather than anything you did.<\/p>\n If a card refuses to initialise, try a different card before changing anything else. It resolves this more often than any other single step.<\/p>\n The library uses short DOS-style names: up to eight characters, a dot, up to three more<\/strong>. Case is not preserved either. Use capitals and keep to the limit.<\/p>\n SPI needs four pins, and on an Uno they are fixed: That means A card can draw a surprising burst of current while writing, up to a hundred milliamps or so. On USB power with nothing else connected, that is fine. Alongside a display and a couple of sensors, it is the thing that makes a board reset mid-write.<\/p>\n A reset mid-write is worse than it sounds, because it can leave the file system damaged rather than just losing a line. The defence is in the code below: open the file, write, close it, every time. A closed file is a safe file.<\/p>\n Keep these leads short. SPI at a few megahertz over long loose jumper wires is a real source of intermittent failures, and the symptom is a card that initialises sometimes.<\/p>\n Prove the card works before writing anything that matters.<\/p>\n A blank card lists nothing, which is correct. What matters is \u201cready\u201d rather than \u201cfailed\u201d.<\/p>\n Four decisions here are the difference between a logger and a disappointment.<\/p>\n The file is opened and closed around every write.<\/strong> Holding it open is faster and loses everything buffered if power goes. For a reading a minute, the speed does not matter and the safety does.<\/p>\n The sketch keeps working without a card.<\/strong> The header is written only when the file does not yet exist<\/strong>, so restarting the logger appends to the same file rather than scattering headers through it.<\/p>\n It is CSV<\/strong>, which opens directly in any spreadsheet. One line per reading, commas between fields, no quotes needed for plain numbers.<\/p>\n The sketch above builds each line with If you log frequently, build the line into a fixed \u201cready\u201d on the serial monitor, a Take the card to a computer and open the file in a spreadsheet. The columns should separate automatically, and a chart of the temperature column is about three clicks away. That moment is the point of the whole tutorial.<\/p>\n All text, wiring guidance and code in this tutorial are original Siratek work.<\/p>\n Card capacity and formatting limits are properties of the standard library rather than of this module. No third-party tutorial text, diagrams, photographs or code has been reproduced here.<\/p>\n <\/p>\n<\/body>","protected":false},"excerpt":{"rendered":" A micro SD card socket on a small board, so an Arduino can write files. Readings go to a card, the card goes into a computer, and you open the result in a spreadsheet.<\/p>\n","protected":false},"featured_media":0,"template":"","siratek_tutorial_level":[],"class_list":["post-52346","siratek_tutorial","type-siratek_tutorial","status-publish","hentry"],"yoast_head":"\nLVC125A<\/code> beside the socket, the regulator the larger three-legged part with a metal tab.<\/p>\nVCC<\/code> to the Uno\u2019s 5V<\/code> pin. The regulator needs the higher voltage to work from; feed it 3.3 V instead and it has nothing to regulate.<\/p>\nCards, and why one may simply not work<\/h3>\n
\n
Filenames must be 8.3<\/h3>\n
LOG.CSV<\/code> and DATA0001.TXT<\/code> are fine. sensor-readings.csv<\/code> is not, and the failure is silent: the file is simply never created, and every write succeeds into nothing.<\/p>\nThe pins it takes, and what that costs<\/h3>\n
D11<\/code>, D12<\/code> and D13<\/code> for data and clock, plus a chip select which can be any pin but conventionally is D10<\/code>.<\/p>\nD10<\/code> to D13<\/code> are gone<\/strong>, and they are the same pins the MAX7219 tutorial used. Both can share the bus if each has its own chip select, but it is worth knowing before you plan a project around all three.<\/p>\nPower, which is the other common fault<\/h3>\n
Pin reference<\/h2>\n
\n\n
\n \nModule pin<\/th>\n Connect to<\/th>\n Purpose<\/th>\n Notes<\/th>\n<\/tr>\n<\/thead>\n \n GND<\/code><\/td>\nUno GND<\/code><\/td>\nGround<\/td>\n <\/td>\n<\/tr>\n \n VCC<\/code><\/td>\nUno 5V<\/code><\/td>\nPower<\/td>\n The board makes its own 3.3 V<\/td>\n<\/tr>\n \n MISO<\/code><\/td>\nUno D12<\/code><\/td>\nData from the card<\/td>\n <\/td>\n<\/tr>\n \n MOSI<\/code><\/td>\nUno D11<\/code><\/td>\nData to the card<\/td>\n <\/td>\n<\/tr>\n \n SCK<\/code><\/td>\nUno D13<\/code><\/td>\nClock<\/td>\n <\/td>\n<\/tr>\n \n CS<\/code><\/td>\nUno D10<\/code><\/td>\nChip select<\/td>\n Any pin, but the library defaults near this<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Wiring steps<\/h2>\n
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GND<\/code> to GND<\/code>, VCC<\/code> to 5V<\/code>.<\/li>\nMISO<\/code> to D12<\/code>, MOSI<\/code> to D11<\/code>, SCK<\/code> to D13<\/code>.<\/li>\nCS<\/code> to D10<\/code>.<\/li>\nSoftware and libraries<\/h2>\n
SD<\/code> ships with the Arduino IDE. Nothing to install.<\/p>\nMinimal working example<\/h2>\n
\/\/ Siratek: confirm the card initialises and list what is on it.\n\n#include <SPI.h>\n#include <SD.h>\n\nconst int chipSelect = 10;\n\nvoid setup() {\n Serial.begin(9600);\n while (!Serial) {\n ;\n }\n\n Serial.print(\"Siratek: starting the card... \");\n\n if (!SD.begin(chipSelect)) {\n Serial.println(\"failed.\");\n Serial.println(\" Check the card is FAT32 and 32 GB or smaller,\");\n Serial.println(\" check CS is on pin 10, and try another card.\");\n return;\n }\n\n Serial.println(\"ready.\");\n\n File root = SD.open(\"\/\");\n while (true) {\n File entry = root.openNextFile();\n if (!entry) {\n break;\n }\n Serial.print(\" \");\n Serial.print(entry.name());\n Serial.print(\" \");\n Serial.println(entry.size());\n entry.close();\n }\n root.close();\n}\n\nvoid loop() {\n}<\/code><\/pre>\nLogging readings as CSV<\/h3>\n
\/\/ Siratek: a temperature log with a real timestamp, one line per minute.\n\n#include <SPI.h>\n#include <SD.h>\n#include <Wire.h>\n#include <RTClib.h>\n\nconst int chipSelect = 10;\nconst char* filename = \"LOG.CSV\";\n\nRTC_DS3231 rtc;\n\nconst unsigned long interval = 60000UL;\nunsigned long lastWrite = 0;\n\nbool cardReady = false;\n\nvoid setup() {\n Serial.begin(9600);\n\n if (!rtc.begin()) {\n Serial.println(\"Siratek: no clock found.\");\n }\n\n cardReady = SD.begin(chipSelect);\n if (!cardReady) {\n Serial.println(\"Siratek: no card. Logging disabled, serial only.\");\n return;\n }\n\n \/\/ Write a header once, when the file is first created.\n if (!SD.exists(filename)) {\n File f = SD.open(filename, FILE_WRITE);\n if (f) {\n f.println(\"timestamp,temperature_c\");\n f.close();\n }\n }\n\n lastWrite = millis() - interval; \/\/ log once immediately\n}\n\nvoid logLine(const String& line) {\n Serial.println(line);\n\n if (!cardReady) {\n return;\n }\n\n \/\/ Open, write, close, every time. A closed file survives a power cut.\n File f = SD.open(filename, FILE_WRITE);\n if (f) {\n f.println(line);\n f.close();\n } else {\n Serial.println(\" could not open the file\");\n }\n}\n\nvoid loop() {\n if (millis() - lastWrite < interval) {\n return;\n }\n lastWrite = millis();\n\n DateTime now = rtc.now();\n float temperature = rtc.getTemperature();\n\n String line = String(now.year()) + \"-\" +\n String(now.month()) + \"-\" +\n String(now.day()) + \" \" +\n String(now.hour()) + \":\" +\n String(now.minute()) + \":\" +\n String(now.second()) + \",\" +\n String(temperature, 1);\n\n logLine(line);\n}<\/code><\/pre>\ncardReady<\/code> means a missing card costs you the log, not the project. A logger that refuses to run because the card is out is worse than one that carries on and tells you.<\/p>\nUsing String, and when not to<\/h3>\n
String<\/code>, which is readable and fine at one line a minute.<\/p>\nString<\/code> allocates memory as it goes, and on a board with 2 KB of RAM, repeated allocation gradually fragments the heap. In a loop running many times a second, that ends in a sketch that runs for hours and then freezes.<\/p>\nchar<\/code> buffer with snprintf()<\/code> instead. For a slow logger, leave it alone and spend the effort elsewhere.<\/p>\nExpected result<\/h2>\n
LOG.CSV<\/code> appearing on the card, and one line added per minute.<\/p>\nTroubleshooting<\/h2>\n
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\n \nSymptom<\/th>\n Likely cause<\/th>\n Check or fix<\/th>\n<\/tr>\n<\/thead>\n \n Initialisation failed<\/td>\n Card too large or wrong format<\/td>\n 32 GB or smaller, FAT32<\/td>\n<\/tr>\n \n Initialisation failed, card fine<\/td>\n CS<\/code> on the wrong pin<\/td>\nMatch the pin in SD.begin()<\/code><\/td>\n<\/tr>\n\n Fails intermittently<\/td>\n Long or loose jumper leads<\/td>\n Shorten and reseat them<\/td>\n<\/tr>\n \n Fails with one card, works with another<\/td>\n Cheap or counterfeit card<\/td>\n Use a known brand<\/td>\n<\/tr>\n \n File never appears<\/td>\n Filename longer than 8.3<\/td>\n LOG.CSV<\/code>, not sensor-log.csv<\/code><\/td>\n<\/tr>\n\n File exists but is empty<\/td>\n Not closed before power was lost<\/td>\n Close after every write<\/td>\n<\/tr>\n \n Board resets while writing<\/td>\n Current burst during a write<\/td>\n Check the power budget<\/td>\n<\/tr>\n \n Card corrupted after a reset<\/td>\n File open when power went<\/td>\n Open, write, close each time<\/td>\n<\/tr>\n \n Works alone, not with a display<\/td>\n Both on SPI<\/td>\n Separate chip select pins<\/td>\n<\/tr>\n \n Runs for hours then freezes<\/td>\n String<\/code> fragmenting the heap<\/td>\nUse snprintf()<\/code> into a fixed buffer<\/td>\n<\/tr>\n\n Timestamps all identical<\/td>\n Clock not set<\/td>\n See Keeping Time with a DS3231<\/em><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Next steps<\/h2>\n
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Sources and attribution<\/h2>\n
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74LVC125A<\/code> level shifter and the SOT-223 regulator on this module were read from the Siratek product photographs for item 6573, which is what establishes that the board is safe on a 5 V Arduino rather than 3.3 V only.<\/li>\nSD<\/code> library documentation for the 8.3 filename limit and the supported formats.<\/li>\n<\/ul>\n