.equ BAUDRATE_LOW = UBRR3L .equ BAUDRATE_HIGH = UBRR3H .equ USART_C = UCSR3C .equ USART_B = UCSR3B .equ USART_A = UCSR3A .equ USART_DATA = UDR3 .equ URXCaddr = URXC3addr .equ UDREaddr = UDRE3addr .equ bm_USART_RXRD = 1 << RXC3 .equ bm_USART_TXRD = 1 << UDRE3 .equ bm_ENABLE_TX = 1 << TXEN3 .equ bm_ENABLE_RX = 1 << RXEN3 .equ bm_ENABLE_INT_RX = 1<