CesRoc Projects - Hardware - Microcontroller - PIC

USB Small Example
This is a simple example developed using the PIC32 USB Starter Kit II. The example demonstrates how to send debug messages to the MPLAB IDE, open a file, write information to it, and then close the file. The USB Starter Kit includes three push buttons and three LEDs. In this project: The first two buttons are used to write messages to the file; The third button is used to close the file. Each time a button is pressed, its corresponding LED lights up.
The Starter Kit provides a debug library that supports basic console I/O. To send a message to the console, you only need to call: DBINIT() and then DBPRINTF("your text").
DBINIT(); //Initialize the IO channel DBPRINTF("Test date and time is ... (" __DATE__ "," __TIME__ ")\n"); //prints the line on the console DBPRINTF("Hello, when you press first and second pushbutton it saves new line in the file,\n"); DBPRINTF("if you press the third pushbutton the file is closed.\n");
It also includes libraries for file system and USB handling. The example below illustrates how to open, write to, and close a file:
USBTasks(); // if USB stick is plugged if(USBHostMSDSCSIMediaDetect()) { deviceAttached = TRUE; if(FSInit()) { myFile = FSfopen("test.txt","w"); FSfwrite("Test started.",1,15,myFile); FSfwrite("\r\n",1,2,myFile); FSfclose(myFile); while(deviceAttached == TRUE) { USBTasks(); } } }
Note: The third parameter of FSfwrite() defines the string size — it is recommended to use the actual size of your string as the parameter. You can download the complete example code below. This project also uses LEDs and push buttons to demonstrate basic hardware interaction.
int main(void) { PicInit(); deviceAttached = FALSE; USBInitialize(0); DBINIT(); DBPRINTF("Test date and time is ... (" __DATE__ "," __TIME__ ")\n"); DBPRINTF("Hello, when you press first and second pushbutton it saves new line in the file,\n"); DBPRINTF("if you press the third pushbutton the file is closed.\n"); while(1) { USBTasks(); if(USBHostMSDSCSIMediaDetect()) { deviceAttached = TRUE; if(FSInit()) { myFile = FSfopen("test.txt","w"); FSfwrite("Test started.",1,15,myFile); FSfwrite("\r\n",1,2,myFile); while(deviceAttached == TRUE) { USBTasks(); if (BUTTON_1==FALSE) { LED_1 = 1; LED_2 = 0; LED_3 = 0; DBPRINTF("You pressed the first!\n"); FSfwrite("You pressed the first!",1,23,myFile); FSfwrite("\r\n",1,2,myFile); } if (BUTTON_2==FALSE) { LED_1 = 0; LED_2 = 1; LED_3 = 0; DBPRINTF("You pressed the second!\n"); FSfwrite("You pressed the second!",1,23,myFile); FSfwrite("\r\n",1,2,myFile); } if (BUTTON_3==FALSE) { LED_1 = 0; LED_2 = 0; LED_3 = 1; DBPRINTF("You pressed the third, file closed!\n"); FSfwrite("You pressed the third. Close the file!",1,40,myFile); FSfwrite("\r\n",1,2,myFile); FSfclose(myFile); } } } } } return 0; }
As mentioned, this is just a basic example. A possible next step is to connect the PIC32 to an Arduino to measure temperature and save the data on a USB flash drive.

Software
Source code

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USB Small Example

Software