I am working with an esp32 board and programming to interface with an SD card reader/writer. I opened the example sketch for SD and esp32 named SD_time.ino. I'll paste the code below. What I don't understand is why the setup() function has an open curly brace but DOES NOT have a close curly brace at the end of the function. Why does this compile as it is written? When I insert a closing curly brace at the end, it fails the complie. This sems strange to me. What might I be missing?
/*
* pin 1 - not used | Micro SD card |
* pin 2 - CS (SS) | /
* pin 3 - DI (MOSI) | |__
* pin 4 - VDD (3.3V) | |
* pin 5 - SCK (SCLK) | 8 7 6 5 4 3 2 1 /
* pin 6 - VSS (GND) | ▄ ▄ ▄ ▄ ▄ ▄ ▄ ▄ /
* pin 7 - DO (MISO) | ▀ ▀ █ ▀ █ ▀ ▀ ▀ |
* pin 8 - not used |_________________|
* ║ ║ ║ ║ ║ ║ ║ ║
* ╔═══════╝ ║ ║ ║ ║ ║ ║ ╚═════════╗
* ║ ║ ║ ║ ║ ║ ╚══════╗ ║
* ║ ╔═════╝ ║ ║ ║ ╚═════╗ ║ ║
* Connections for ║ ║ ╔═══╩═║═║═══╗ ║ ║ ║
* full-sized ║ ║ ║ ╔═╝ ║ ║ ║ ║ ║
* SD card ║ ║ ║ ║ ║ ║ ║ ║ ║
* Pin name | - DO VSS SCK VDD VSS DI CS - |
* SD pin number | 8 7 6 5 4 3 2 1 9 /
* | █/
* |__▍___▊___█___█___█___█___█___█___/
*
* Note: The SPI pins can be manually configured by using `SPI.begin(sck, miso, mosi, cs);`.
* Alternatively you can change only the CS pin with `SD.begin(CSpin)` and keep the default settings for other pins.
*
+----------+
* | SPI Pin Name | ESP8266 | ESP32 | ESP32‑S2 | ESP32‑S3 | ESP32‑C3 | ESP32‑C6 | ESP32‑H2 |
* +==============+=========+=======+==========+==========+==========+==========+==========+
* | CS (SS) | GPIO15 | GPIO5 | GPIO34 | GPIO10 | GPIO7 | GPIO18 | GPIO0 |
* +--------------+---------+-------+----------+----------+----------+----------+----------+
* | DI (MOSI) | GPIO13 | GPIO23| GPIO35 | GPIO11 | GPIO6 | GPIO19 | GPIO25 |
* +--------------+---------+-------+----------+----------+----------+----------+----------+
* | DO (MISO) | GPIO12 | GPIO19| GPIO37 | GPIO13 | GPIO5 | GPIO20 | GPIO11 |
* +--------------+---------+-------+----------+----------+----------+----------+----------+
* | SCK (SCLK) | GPIO14 | GPIO18| GPIO36 | GPIO12 | GPIO4 | GPIO21 | GPIO10 |
* +--------------+---------+-------+----------+----------+----------+----------+----------+
*
* For more info see file README.md in this library or on URL:
* https://github.com/espressif/arduino-esp32/tree/master/libraries/SD
*/
#include "FS.h"
#include "SD.h"
#include "SPI.h"
#include <time.h>
#include <WiFi.h>
const char *ssid = "your-ssid";
const char *password = "your-password";
long timezone = 1;
byte daysavetime = 1;
/*
Uncomment and setup pins you want to use for the SPI communication
#define REASSIGN_PINS
int sck = -1;
int miso = -1;
int mosi = -1;
int cs = -1;
*/
void listDir(fs::FS &fs, const char *dirname, uint8_t levels) {
Serial.printf("Listing directory: %s\n", dirname);
File root = fs.open(dirname);
if (!root) {
Serial.println("Failed to open directory");
return;
}
if (!root.isDirectory()) {
Serial.println("Not a directory");
return;
}
File file = root.openNextFile();
while (file) {
if (file.isDirectory()) {
Serial.print(" DIR : ");
Serial.print(file.name());
time_t t = file.getLastWrite();
struct tm *tmstruct = localtime(&t);
Serial.printf(
" LAST WRITE: %d-%02d-%02d %02d:%02d:%02d\n", (tmstruct->tm_year) + 1900, (tmstruct->tm_mon) + 1, tmstruct->tm_mday, tmstruct->tm_hour,
tmstruct->tm_min, tmstruct->tm_sec
);
if (levels) {
listDir(fs, file.path(), levels - 1);
}
} else {
Serial.print(" FILE: ");
Serial.print(file.name());
Serial.print(" SIZE: ");
Serial.print(file.size());
time_t t = file.getLastWrite();
struct tm *tmstruct = localtime(&t);
Serial.printf(
" LAST WRITE: %d-%02d-%02d %02d:%02d:%02d\n", (tmstruct->tm_year) + 1900, (tmstruct->tm_mon) + 1, tmstruct->tm_mday, tmstruct->tm_hour,
tmstruct->tm_min, tmstruct->tm_sec
);
}
file = root.openNextFile();
}
}
void createDir(fs::FS &fs, const char *path) {
Serial.printf("Creating Dir: %s\n", path);
if (fs.mkdir(path)) {
Serial.println("Dir created");
} else {
Serial.println("mkdir failed");
}
}
void removeDir(fs::FS &fs, const char *path) {
Serial.printf("Removing Dir: %s\n", path);
if (fs.rmdir(path)) {
Serial.println("Dir removed");
} else {
Serial.println("rmdir failed");
}
}
void readFile(fs::FS &fs, const char *path) {
Serial.printf("Reading file: %s\n", path);
File file = fs.open(path);
if (!file) {
Serial.println("Failed to open file for reading");
return;
}
Serial.print("Read from file: ");
while (file.available()) {
Serial.write(file.read());
}
file.close();
}
void writeFile(fs::FS &fs, const char *path, const char *message) {
Serial.printf("Writing file: %s\n", path);
File file = fs.open(path, FILE_WRITE);
if (!file) {
Serial.println("Failed to open file for writing");
return;
}
if (file.print(message)) {
Serial.println("File written");
} else {
Serial.println("Write failed");
}
file.close();
}
void appendFile(fs::FS &fs, const char *path, const char *message) {
Serial.printf("Appending to file: %s\n", path);
File file = fs.open(path, FILE_APPEND);
if (!file) {
Serial.println("Failed to open file for appending");
return;
}
if (file.print(message)) {
Serial.println("Message appended");
} else {
Serial.println("Append failed");
}
file.close();
}
void renameFile(fs::FS &fs, const char *path1, const char *path2) {
Serial.printf("Renaming file %s to %s\n", path1, path2);
if (fs.rename(path1, path2)) {
Serial.println("File renamed");
} else {
Serial.println("Rename failed");
}
}
void deleteFile(fs::FS &fs, const char *path) {
Serial.printf("Deleting file: %s\n", path);
if (fs.remove(path)) {
Serial.println("File deleted");
} else {
Serial.println("Delete failed");
}
}
void setup() {
Serial.begin(115200);
// We start by connecting to a WiFi network
Serial.println();
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
Serial.println("Contacting Time Server");
configTime(3600 * timezone, daysavetime * 3600, "time.nist.gov", "0.pool.ntp.org", "1.pool.ntp.org");
struct tm tmstruct;
delay(2000);
tmstruct.tm_year = 0;
getLocalTime(&tmstruct, 5000);
Serial.printf(
"\nNow is : %d-%02d-%02d %02d:%02d:%02d\n", (tmstruct.tm_year) + 1900, (tmstruct.tm_mon) + 1, tmstruct.tm_mday, tmstruct.tm_hour, tmstruct.tm_min,
tmstruct.tm_sec
);
Serial.println("");
#ifdef REASSIGN_PINS
SPI.begin(sck, miso, mosi, cs);
if (!SD.begin(cs)) {
#else
if (!SD.begin()) {
#endif
Serial.println("Card Mount Failed");
return;
}
uint8_t cardType = SD.cardType();
if (cardType == CARD_NONE) {
Serial.println("No SD card attached");
return;
}
Serial.print("SD Card Type: ");
if (cardType == CARD_MMC) {
Serial.println("MMC");
} else if (cardType == CARD_SD) {
Serial.println("SDSC");
} else if (cardType == CARD_SDHC) {
Serial.println("SDHC");
} else {
Serial.println("UNKNOWN");
}
uint64_t cardSize = SD.cardSize() / (1024 * 1024);
Serial.printf("SD Card Size: %lluMB\n", cardSize);
listDir(SD, "/", 0);
removeDir(SD, "/mydir");
createDir(SD, "/mydir");
deleteFile(SD, "/hello.txt");
writeFile(SD, "/hello.txt", "Hello ");
appendFile(SD, "/hello.txt", "World!\n");
listDir(SD, "/", 0);
}
void loop() {}