; Testprogramm for the RS232-Board with LCD
      ; Copyright by Thomas Wedemeyer 1996

      ; Definition Prozessortyp

            cpu 80515 include stddef51.inc

            RAMBASE set 8000h ;beginning of RAM area
            LC_IW set 0000h ;LCD Instruction Register Write
            LC_DW set 0001h ;LCD Data Register Write
            LC_IR set 0002h ;LCD Instruction Register Read
            LC_DR set 0003h ;LCD Data Register Read
            ESC set 1bh

            ORG RAMBASE

      ;*****************************************************************************
      ; LCD initialisation
      ;*****************************************************************************
      LCD_init:
            mov dptr,#LC_IW ; load adresspointer with LC_IW
            mov a,#38h ; function set: 8-bit interface, 2 lines
            movx @dptr,a ; movx accu to pointer-adress (LC_IW)
            mov th0,#27h ; load timer0 with 10ms
            mov tl0,#10h ;
            mov tmod,#02h ; timer0 mode 1
            setb tr0 ; start timer0
      initl0: jnb tf0,initl0 ; wait until timer is 0
            clr tf0 ; clear tf0
            mov a,#38h ; function set: 8-bit interface, 2 lines
            movx @dptr,a ; movx accu to pointer-adress (LC_IW)
            mov th0,#27h ; load timer0 with 10ms
            mov tl0,#10h ;
            setb tr0 ; start timer0
      initl1: jnb tf0,initl1 ; wait until timer is 0
            clr tf0 ; clear tf0
            mov a,#38h ; function set: 8-bit interface, 2 lines
            movx @dptr,a ; movx accu to pointer-adress (LC_IW)
            acall LC_BUSY ; wait until LCD ready
            mov dptr,#LC_IW ;
            mov a,#06h ; Entry Mode = Increment
            movx @dptr,a ; Write instruction
            acall LC_BUSY ; wait until LCD ready
            mov dptr,#LC_IW ;
            mov a,#0fh ; Display control = on, cursor on, flash on
            movx @dptr,a ; Write instruction
            acall LC_BUSY ; wait until LCD ready
            mov dptr,#LC_IW ;
            mov a,#01h ; clear display
            movx @dptr,a ; Write instruction
            acall LC_BUSY ; wait until LCD ready

      ;*****************************************************************************
      ; Start mainprogramm
      ;*****************************************************************************
      main:

            acall LC_WRITE ; Write CHR to LCD
            db "RS232-SAB80C535"
            db ESC ;
      test: jmp test

      ;*****************************************************************************
      ; Wait for the Display
      ;*****************************************************************************
      LC_BUSY:
            push dpl ; push adress-pointer to stack
            push dph ;
            mov dptr,#LC_IR ; load adress-pointer with LC_IR
      LC_BUS0:
            movx a,@dptr ; move LC_IR to accu
            jb acc.7,LC_BUS0 ;
            pop dph ; pop stack to adress-pointer
            pop dpl ;
            ret

      ;*****************************************************************************
      ; Write Char to LCD
      ;*****************************************************************************
      LC_WRITE:
            POP DPH ;LOAD DPTR WITH FIRST CHAR
            POP DPL
            CLR A ;(ZERO OFFSET)
            MOVC A,@A+DPTR ;FETCH FIRST CHAR IN STRING
      LC_WRI_1:
            push dpl ; save DPTR
            push dph ;
            mov dptr,#LC_DW ; Load LC_Data register adress
            movx @dptr,A ;OUTPUT NEXT CHARACTER
            acall LC_BUSY ;
            pop dph ; load char adress
            pop dpl ;
            INC DPTR ;BUMP POINTER
            CLR A
            MOVC A,@A+DPTR ;GET NEXT CHARACTER
            CJNE A,#ESC,LC_WRI_1 ;LOOP UNTIL ESCAPE READ
            MOV A,#1
            JMP @A+DPTR ;RETURN TO CODE AFTER ESCAPE
            ;