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- ADC to LED problem MC68HC12
ADC to LED problem MC68HC12
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ADC to LED problem MC68HC12
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I have code that is not working for the MC68HC12, it takes 0-5V into the
ADC and does some math to convert to revolutions per second and outputs
to 2 LED's. Could someone analyze the code to tell me in general what
might be wrong with the code. Some where I've think I've made a basic
mistake, I have not used the ADC before. I get not display on LED's.
The code is also attached.
include 'MC9S12C128.inc' org $800 movb #$FF, DDRB movb #$C0, ATDCTL2 movb #$00, ATDCTL3 movb #$00, ATDCTL4 ldaa #1Wait deca bne Wait movb #$20, ATDCTL5 ldab ATDDR0H ;AB will hold the input loop clra ;clear AA- AB holds converted input ldab #$80 ;test data -to be commented out ldx #51 ;relationship between digital number and BCD idiv ;as defined in prelab stx holder ;holder holds the ones place ldaa #10 ;there will be a remainder. Want at least 1 decimal point accuracy mul ldx #51 ;repeat dividing by 51 idiv stx holder2 ;holder2 holds the tenths place ldd holder ;what follows is multiplying both the ones and teneths place by (18/5) ldy #18 ;as shown in pre-lab work emul std holder ldd holder2 ldy #18 emul std holder2 ldd holder ldx #5 idiv stx holder ldd holder2 ldx #5 idiv stx holder2 ldd holder2 ;we then want to divide holder2 (tenths place) by 10 and add it to holder ldx #10 ;in order to get 1 number with which to continue calculation of RSP idiv xgdx addd holder std Va ldd #14 ;we want to add 1.4 to Va, per pre-lab work. divide 14 by 10 to achieve this ldx #10 idiv stx holder std holder2 ;remainder stored in holder2 ldd Va addd holder std Va ldd holder2 ldx #10 idiv ldd Va addd 0,x std Va ldy #2 ;multiply by 2 emul std Va ldd #46 ;multiply by .46 = (46/100) ldx #100 idiv stx Va ;Va now contains RPS ldd Va cpd #10 bge output1 ldaa #00 output1 ldd Va ;checks value of tens place of RPS ldx #10 idiv stx tensplace ldd tensplace cpd #1 beq one1 ldd tensplace cpd #2 beq two1 ldd tensplace cpd #3 beq three1 ldd tensplace cpd #4 beq four1 ldd tensplace cpd #5 beq five1 ldd tensplace cpd #6 beq six1 ldd tensplace cpd #7 beq seven1 ldd tensplace cpd #8 beq eight1 ldd tensplace beq nine1 ldaa #00 one1 ldaa one ;will load appropriate hex number to have 7-seg display output two1 ldaa two ;appropriate numberthree1 ldaa threefour1 ldaa fourfive1 ldaa fivesix1 ldaa sixseven1 ldaa seveneight1 ldaa eightnine1 ldaa nine staa tensplace ldd Va ;checks value of tens place of RPS ldx #10 idiv stx onesplace ldd onesplace cpd #1 beq one2 ldd onesplace cpd #2 beq two2 ldd onesplace cpd #3 beq three2 ldd onesplace cpd #4 beq four2 ldd onesplace cpd #5 beq five2 ldd onesplace cpd #6 beq six2 ldd onesplace cpd #7 beq seven2 ldd onesplace cpd #8 beq eight2 ldd onesplace beq nine1 ldaa #00 one2 ldaa one ;will load appropriate hex number to have 7-seg display output two2 ldaa two ;appropriate numberthree2 ldaa threefour2 ldaa fourfive2 ldaa fivesix2 ldaa sixseven2 ldaa seveneight2 ldaa eightnine2 ldaa nine staa onesplace movb #$7C, DDRCAN ;configure portcan for output (from textbook) movb #$FF, DDRP ;configure portp for output movb tensplace, PORTP ;place tens-place output code on portp movb #$40, PORTCAN ;activate pcan6 so that led will illuminate with tensplace digit movb #$30, PORTCAN ;activate pcan5 movb onesplace, PORTP ;illuminate ones-place output code lbra loop swiholder rmb 2 holder2 rmb 2Va rmb 2tensplace rmb 1onesplace rmb 1zero equ $7Eone equ $30two equ $6Dthree equ $79four equ $33five equ $5Bsix equ $5Fseven equ $70eight equ $7Fnine equ $7B PORTP equ $56PORTCAN equ $13E DDRCAN equ $13F
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Ohhh boy, there's all sorts of nonsense in that program... you really need to solidify your program algorithm before doing any assembler coding, or else you'll get lost easily (especially in absolute assembler)!
Are you trying to use just 2 LED's on a 7-segment display?
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Well, what's not working?
Are you using a development board for this chip, if so, which one?
Edit:
Ok, found it.
Your only checking the first data that came in... which is probably junk data becuase you didn't wait for a conversion to finish.
Scan mode does indeed make the ADC run continously, BUT, you have to have your program continuosly check to see if a conversion is completed. This can be done by checking the SCF flag in ATDSTAT0.
For ATD operations, you need to:
- Configure the ADC
- Start a conversion when ready
- Wait for a conversion to be completed (more advanced programs can do other stuff while it's waiting)
- Once a conversion is complete, get the data and process it
- Start another conversion (omit this step if SCAN mode is enabled)
- Repeat steps 3 to 5
Rethink your algorithm, and try placing down on paper in a graphical form, such as a flow chart.
It would probably be a good idea to disable Scan mode and have the program start a new conversion manually for the time being. Writing to the ATDCTL5 register will always start a new conversion, even if one is currently being process by the ADc module.
Highly suggest you read over Cahpter 8 of your MCU's user manual, and also ensure that your develpment board isn't using an ADC channel for something else.
