...
#define TX_BUFFER_SIZE 8
char tx_buffer[TX_BUFFER_SIZE];
unsigned char tx_wr_index,tx_rd_index,tx_counter;
// USART Transmitter interrupt service routine
#pragma savereg-
interrupt [USART_TXC] void uart_tx_isr(void)
{
#asm
push r26
push r27
pus...