Subversion Repositories copyblaze

             ;Interrupt example

             ;

                         waveform_port          .EQU    02      ;bit0 will be data

             counter_port               .EQU    04

             pattern_10101010   .EQU    0xAA

             interrupt_counter  .EQU    sA

             ;

      start: LOAD       interrupt_counter       , 00                            ;reset interrupt counter

             LOAD       s2                                      , pattern_10101010      ;initial output condition

             EINT                                                                                       ; enable interrupts

             ;

 drive_wave: OUTPUT s2, waveform_port

             LOAD       s0, 0x07                            ;delay size

       loop: SUB        s0, 0x01                             ;delay loop

             JUMP       NZ, loop

             XOR        s2, 0xFF                             ;toggle waveform

             JUMP       drive_wave

             ;

             .ORG       0x080

int_routine:

                         ADD    interrupt_counter, 01              ;increment counter

             OUTPUT interrupt_counter, counter_port

             RETI       ENABLE

             ;

             .ORG       0x3FF                            ;set interrupt vector

             JUMP int_routine