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+<pagebreak>
+====== USB ======
+//Required knowledge:
+[HW] [[et:hardware:homelab:controller]],
+[LIB] [[et:software:homelab:library:usb]], \\
+[LIB] [[et:software:homelab:library:module:lcd_graphic]]//
+===== Theory =====
+===== Practice =====
+HomeLab III generation controllers have a USB connection directly to the microcontroller, which enables a direct connection between the microcontroller and a computer.
+To test the example program, you need a terminal-type application, e.g., HyperTerminal (Windows XP). On Linux you can use minicom. Characters typed in the window are shown on the LCD screen. Pressing Enter changes the line on the LCD screen. When the '?' symbol is sent, the ADC reading is returned.
+<code c>
+// HomeLab USB interface example program
+// Text sent from a computer or another device is displayed on the LCD screen
+#include <homelab/module/lcd_gfx.h>
+#include <homelab/usb/usb.h>
+#include <homelab/adc.h>
+// Main program
+int main(void)
+{
+	char c;
+	unsigned char row = 1;
+	char buf[20];
+	// LCD initialization and greeting message
+	lcd_gfx_init();
+	lcd_gfx_write_string("Ootan teadet");
+	lcd_gfx_goto_char_xy(0, row);
+	// Start ADC
+	adc_init(ADC_REF_AVCC,ADC_PRESCALE_128);
+	// USB interface setup
+	usb_init();
+	// Infinite loop
+	while (1)
+	{
+		// Read a character from USB and check if one was received
+		c = usb_read_byte();
+		if (c >= 0)
+		{
+			// Send the character back via USB
+			usb_send_char(c);
+			if (c == '\r') // Is it a newline?
+			{
+				// Switch line
+				if (row < 12) row++;
+				else row = 0;
+				// Clear previous message from the line
+				lcd_gfx_clear_line(row);
+				// Cursor to the beginning of the new line
+				lcd_gfx_goto_char_xy(0,row);
+			}
+			else
+			{
+				// Print character directly to the screen
+				lcd_gfx_write_char(c);
+			}
+            // If question mark was sent, also return ADC reading
+            if(c == '?')
+            {
+                sprintf(buf,"\n\r ADC val: %4d. \n\r",adc_get_average_value(15,5));
+                usb_send_string(buf);
+            }
+		}
+		usb_task();
+	}
+}
+</code>

en/examples/communication/usb.txt · Last modified: 2026/02/19 11:30 by 127.0.0.1