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[/] [light52/] [trunk/] [test/] [hello_asm/] [src/] [hello.a51] - Blame information for rev 15

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1 3 ja_rd
; hello.a51 -- 'Hello World' on serial console.
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;
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; This small program is meant to be run on a light52 MCU on actual hardware,
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; as a first sanity check.
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;
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; This version of the program does not use interrupts.
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;
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; If this program runs and displays its message on a terminal, you may then be
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; sure that your development environment is working.
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        ; Include the definitions for the light52 derivative
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        $nomod51
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        $include (light52.mcu)
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        ;-- Data variable definitions ------------------------------------------
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        ; These are general purpose variables for use in subroutines.
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        ; They must be saved and restored before use.
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        var0    data    030h
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        ; We'll place the stack above the reg banks and bit addressable area,
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        ; leaving some space for our stuff (030h to 03fh).
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        stack   set     040h
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        ;-- Macros -------------------------------------------------------------
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        ;-- Reset & interrupt vectors ------------------------------------------
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        org     00h
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        ljmp    start               ;
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        org     03h
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        ljmp    irq_unused
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        org     0bh
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        ljmp    irq_timer
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        org     13h
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        ljmp    irq_unused
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        org     1bh
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        ljmp    irq_unused
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        org     23h
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        ljmp    irq_uart
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        ;-- Main test program --------------------------------------------------
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        org     30h
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start:
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        ; Set up stack.
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        mov     SP,#stack
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        ; Clear ports P0 and P1, bearing in mind that on the demo platform,
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        ; P0 is looped back into P2 and P1 to P3, and P1 is also connected to
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        ; the external irq inputs.
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        mov     P0,#000h
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        mov     P1,#000h
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        ; Initialize serial port...
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        ; (actually, leave it with its default configuration: 19200-8-N-1)
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        ; ...and dump the hello string to the serial port.
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        mov     DPTR,#text0
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        call    po_cstr
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        ; Ok, now
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        mov     IE,#000h
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        mov     TSTAT,#000h
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        mov     TCH,#0fch
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        mov     TCL,#050h
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        ; Enable timer interrupts and interrupts globally...
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        mov     IE,#082h
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        ; ...and start the timer with autoreload.
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        mov     TSTAT,#030h
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        ; End of test program, enter single-instruction endless loop.
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        ; The timer will keep triggering interrupts indefinitely.
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quit:   ajmp    $
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; po_char:  Print character in ACC to console.
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po_char:
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        mov     SBUF,a
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po_char_loop:
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        jnb     TXRDY,po_char_loop
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        ret
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; po_cstr:  Prints zero-terminated string at XCODE:DPTR to console.
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;           Returns after the whole string has been output.
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po_cstr:
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        push    var0
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        mov     var0,#000h
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po_cstr_loop:
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        mov     a,var0
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        inc     var0
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        movc    a,@a+DPTR
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        jz      po_cstr_done
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        call    po_char
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        sjmp    po_cstr_loop
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po_cstr_done:
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        pop     var0
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        ret
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        ; Unused interrupt routines, will never be reached.
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irq_unused:
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        reti
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irq_uart:
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        reti
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        ; This timer routine is meant to show that the timer works; all it
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        ; does is display a message every timer interrupt.
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irq_timer:
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        setb    TSTAT.0         ; Clear the timer irq flag writing a 1 on it
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        push    DPH             ; Write a short message to the console...
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        push    DPL
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        mov     DPTR,#text1
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        call    po_cstr
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        pop     DPL             ; ...and quit
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        pop     DPH
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        reti
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text0:  db      'Hello World!',13,10,00h,00h
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text1:  db      'Tick!',13,10,00h
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        end

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