InitOptionRegister: page1 movlw B'01000100' ; timer mode with prescaler=32, weak pullups movwf OPTION_REG page0 return InitInterrupts: page1 movlw B'0110000' ; unmask peripheral interrupts and TMR0 movwf INTCON movlw B'00110000' ; unmask USART TX and TX interrupts ;movwf PIE1 ; not yet! page0 return InitMyApp: movlw 0 movwf PORTA,F movwf PORTB,F return Listing 6—The 8051 version of EMIT used a serial interrupt. The semicolon is all that stops you here.