USB2ESP

Using USB Flash Drive Reader/Writer with ESP32

This is a library develop to help using the USB Host Board - USB Flash Drive Reader/Writer, by hobbytronics, with ESP32.

The board already has a chip that process commands sent by UART, but to makes things less complicated I wrote some functions, so I wouldn't have to worry about some details evertime.

The hobbytronics webpage provide some informations about the command that might be usefull. It also has some examples, but for Arduino.

Tasks and Examples

In main/usb2esp_demo_main.c we have some tasks

• ledt

Task that blink a led to show esp is working

• bomber

Task that call software interruption every 10ms. The ideia is to interrupt uart as much as possible

• rx_task

Task that wait for messages from USB.

• tx_task

Task that send commands for USB.

In tx_task I wrote some examples of how to use each functions.

There are 5 examples:

• ex = 0 -> Just show help, in terminal mode. It's usefull to test Baud Rate

• ex = 1 -> Create file and write

• ex = 2 -> Read files

• ex = 3 -> Copy, delete and rename files

• ex = 4 -> Directories operations

• ex = 5 -> Write 128KB string

Note: In ex 5, we write a big string. We did this to show that the function uart_write_bytes feed WDT, and we don't have to worry about this.

Functions

All functions returns the number of bytes sent. It can change in the future for something more usefull.

int sendData(uart_port_t UART_NUM, const char* data)

function that send data by UART_NUM. Internal usage.

int  setTime(uart_port_t  UART_NUM, char*  time);

USB Breakout has internal time clock, but it has no battery so we need to set it everytime we turn it on. Time need to be [hh:mm:ss] format.

int  setDate(uart_port_t  UART_NUM, char*  date);

USB Breakout has internal time clock, but it has no battery so we need to set it everytime we turn it on. Date need to be [yyyy-mm-dd] format.

int  createFile(uart_port_t  UART_NUM, char*  filename);

Create a file in the actual directory with the name filename.

int  appendFile(uart_port_t  UART_NUM, char*  filename);

Open the file in the actual directory named filename .

int  writeOnFile(uart_port_t  UART_NUM, char*  s, int  ssize);

Since the file is opened or created, write the string s with size ssize in the file.

int  closeFile(uart_port_t  UART_NUM);

Send a control+z command, with closes files.

int  dir(uart_port_t  UART_NUM, char*  filename);

It is similar to bash ls. If filename is "", all files are listed. If filename is "*.txt", only txt files are listed.

int  fileSize(uart_port_t  UART_NUM, char*  filename, int  mode);

Command that count file size. It can count number of bytes (mode=BYTE) or number of lines (mode=LINE).

int  readFile(uart_port_t  UART_NUM, char*  filename);

Read the entire file with filename.

int  readLine(uart_port_t  UART_NUM, char*  filename, int  line);

Read only the line line in the file filename.

int  readNextLine(uart_port_t  UART_NUM, char*  filename);

After using the command readLine(), you can use readNextLine() to read the next line of file filename.

int  readSection(uart_port_t  UART_NUM, char*  filename, int  start, int  len);

Read a part of the file filename. This part starts at byte start and end at byte start+len.

int  readNextSection(uart_port_t  UART_NUM, char*  filename, int  len);

After using the command readSection(), you can use readNextSection() to read the next section of file filename. For exemple: filename.txt is "abcdef" readSection(UART_NUM, "filename.txt", 0, 4); //UART receives "abcd" readNextSection(UART_NUM, "filename.txt", 2); //UART receives "ef"

int  copyFile(uart_port_t  UART_NUM, char*  origin, char*  destiny);

Copy file origin to file destiny.

int  delFile(uart_port_t  UART_NUM, char*  filename);

Delete file filename.

int  renameFile(uart_port_t  UART_NUM, char*  oldname, char*  newname);

Rename file oldname to newname.

int  makeDir(uart_port_t  UART_NUM, char*  dirname);

Equivalent to bash mk, create new directory with name dirname.

int  changeDir(uart_port_t  UART_NUM, char*  dirname);

Equivalent to bash cd, change to directory dirname.

int  removeDir(uart_port_t  UART_NUM, char*  dirname);

Remove directory dirname.

int  setBaud(uart_port_t  UART_NUM, char*  baudrate);

Change Baud Rate to baudrate. Allowed values: [2400|4800|9600|14400|19200|38400|57600|115200]

Future improvements

• Binary mode
• Terminal mode