....
code unsigned char TestByte=0x55;
...
void main(void)
{
unsigned char i;
...
SerialPortInitialize ();     // initialize your serial port here
i=TestByte;        // Read byte into IRAM (already tested above)
TransmitByte (i); // Transmit the byte from IRAM          
TransmitByte (TestByte);  // Transmit the byte from Program mem.
for (;;);
}