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+title:AVR echo
+keywords:avr,echo,c,atmega
+
+
+# AVR echo
+This code tested on ATmega16
+
+```c
+#include <avr/io.h>
+ 
+#define FOSC 16000000UL
+#define BAUD 9600
+#define MYUBRR FOSC/16/BAUD-1
+ 
+void USART_Init( unsigned int ubrr)
+{
+    UBRRH = (unsigned char)(ubrr>>8);
+    UBRRL = (unsigned char)ubrr;
+    UCSRB = (1<<RXEN)|(1<<TXEN);
+    UCSRC = (1<<URSEL)|(1<<USBS)|(3<<UCSZ0);
+}
+ 
+int main()
+{
+    char c;
+    USART_Init( MYUBRR );
+    while(1)
+    {
+        while ( !(UCSRA & (1<<RXC))){};
+        c = UDR;
+        while (!(UCSRA & (1<<UDRE))){};
+        UDR = c;
+    }
+    return 0;
+}
+```