16 JMP lblSolutionA general program structure is shown belo

16

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JMP lbl

Solution

A general program structure is shown below:
*********************************************
* Displaying battery voltage and bumper states (s19c32) *
*********************************************
; Definitions
LCD_DAT EQU PORTB        LCD data port, bits - PB7,...,PB0
LCD_CNTR EQU PTJ        LCD control port, bits - PE7(RS),PE4(E)
LCD_E EQU $80            LCD E-signal pin
LCD_RS EQU $40            LCD RS-signal pin
; Variable/data section
ORG $3850
TEN_THOUS RMB 1        10,000 digit
THOUSANDS RMB 1        1,000 digit
HUNDREDS RMB 1            100 digit
TENS RMB 1            10 digit
UNITS RMB 1            1 digit
NO_BLANK RMB 1            Used in ’leading zero’ blanking by BCD2ASC

; Code section
ORG $4000

Entry:
_Startup:
LDS #$4000            initialize the stack pointer
JSR initAD            initialize ATD converter
JSR initLCD            initialize LCD
JSR clrLCD            clear LCD and home cursor
LDX #msg1            display msg1
JSR putsLCD            display msg1
LDAA #$C0            move LCD cursor to the 2nd row
JSR cmd2LCD
LDX #msg2            display msg2
JSR putsLCD            display msg2
lbl MOVB #$90,ATDCTL5        r.just., unsign., sing.conv., mult., ch0, start conv.
BRCLR ATDSTAT0,$80,*        wait until the conversion sequence is complete
LDAA ...            load the ch4 result into AccA
LDAB ...            AccB = 39
MUL                AccD = 1st result x 39
ADDD ...            AccD = 1st result x 39 + 600
JSR int2BCD
JSR BCD2ASC
LDAA ...            move LCD cursor to the 1st row, end of msg1
JSR cmd2LCD                    \"
LDAA TEN_THOUS            output the TEN_THOUS ASCII character
JSR putcLCD                    \"
...                same for THOUSANDS, ’.’ and HUNDREDS
LDAA ...            move LCD cursor to the 2nd row, end of msg2
JSR cmd2LCD                    \"
BRCLR PORTAD0,...,bowON
LDAA #$31    output ’1’ if bow sw OFF
BRA bowOFF
bowON LDAA #$30        output ’0’ if bow sw ON
bowOFF JSR putcLCD
...                output a space character in ASCII

BRCLR PORTAD0,...,sternON
LDAA #$31            output ’1’ if stern sw OFF
BRA sternOFF
sternON LDAA #$30        output ’0’ if stern sw ON
sternOFF JSR putcLCD

JMP lbl
msg1 dc.b \"Battery volt \",0
msg2 dc.b \"Sw status \",0

; Subroutine section
initLCD ...
clrLCD ...
del_50us ...
cmd2LCD ...
putsLCD ...
putcLCD ...
dataMov ...
int2BCD ...
BCD2ASC ...
initAD MOVB #$C0,ATDCTL2    power up AD, select fast flag clear
JSR del_50us            wait for 50 us
MOVB #$00,ATDCTL3        8 conversions in a sequence
MOVB #$85,ATDCTL4        res=8, conv-clks=2, prescal=12
BSET ATDDIEN,$0C        configure pins AN03,AN02 as digital inputs
RTS

; Interrupt vectors
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