How to convert 10bit ADC data to BCD?

[sommes]

How to convert a 10bit digitial signal to three groups of BCD?

For example, the value of 10bit digitial is 789 in decimal.

I would like to ask how to take 7, 8, 9 away and convert each digi to BCD?

p.s. BCD is needed to display a 7-segment display via "BCD to 7-segment
display converter" 74LS48

I am going to use BASIC with Atmel AT90S8535 to do the task.

Thank you very much

 

[Anthony Fremont]

How to convert a 10bit digitial signal to three groups of BCD?

For example, the value of 10bit digitial is 789 in decimal.

I would like to ask how to take 7, 8, 9 away and convert each digi to BCD?

p.s. BCD is needed to display a 7-segment display via "BCD to 7-segment
display converter" 74LS48

I am going to use BASIC with Atmel AT90S8535 to do the task.

Thank you very much

This is for a PIC, but it should be possible to translate it since it's
not that complex. It converts a 16 bit unsigned binary value to 5
packed (two digits per byte) BCD digits. binH and binL contain the 16
bit binary value. count and temp are single byte work areas.

binary_to_bcd
bcf STATUS, 0 ; clear the carry bit
movlw .16
movwf count
clrf tenthousands
clrf thousands_and_hundreds
clrf tens_and_ones
loop16
rlf binL, F
rlf binH, F
rlf tens_and_ones, F
rlf thousands_and_hundreds, F
rlf tenthousands, F
;
decfsz count, F
goto adjDEC
RETLW 0
;
adjDEC
movlw tens_and_ones
movwf FSR
call adjBCD
;
movlw thousands_and_hundreds
movwf FSR
call adjBCD
;
movlw tenthousands
movwf FSR
call adjBCD
;
goto loop16
;
adjBCD
movlw 3
addwf INDF,W
movwf temp
btfsc temp,3 ; test if result > 7
movwf INDF
movlw 0x30
addwf INDF,W
movwf temp
btfsc temp,7 ; test if result > 7
movwf INDF ; save as MSD
RETLW 0

 

[Jon]

The easiest (and slowest) method is to implement a binary down counter
and a BCD up counter. Load the down counter with the binary data.
Clear the BCD up counter. Decrement the down counter to zero. For each
decrement, increment the BCD counter by one.
~
For a more elegant solution, see this article:
BIDEC - A Binary-to-Decimal or Decimal-to-Binary Converter, J. F.
Couleur, IRE Transactions on Electronic Computers, Vol. EC-7,
pp313-316, IRE, 1958.
Regards,
Jon

 

[John Fields]

How to convert a 10bit digitial signal to three groups of BCD?

For example, the value of 10bit digitial is 789 in decimal.

I would like to ask how to take 7, 8, 9 away and convert each digi to BCD?

p.s. BCD is needed to display a 7-segment display via "BCD to 7-segment
display converter" 74LS48

I am going to use BASIC with Atmel AT90S8535 to do the task.

Thank you very much

 

[Tim Wescott]

How to convert a 10bit digitial signal to three groups of BCD?

For example, the value of 10bit digitial is 789 in decimal.

I would like to ask how to take 7, 8, 9 away and convert each digi to BCD?

p.s. BCD is needed to display a 7-segment display via "BCD to 7-segment
display converter" 74LS48

I am going to use BASIC with Atmel AT90S8535 to do the task.

Thank you very much

Divide your number by 10. The remainder is the ones value in BCD.

Divide the quotient by 10. The remainder is the tens value in BCD.

Divide the new quotient by 10. The remainder is the hundreds value in BCD.

The final quotient is either 1 or 0 if you really started from 10 bits.
It is the thousands value.

You can carry this procedure on indefinitely, and it is a general method
for converting from one base to another (so should you want to display
things in base 5, now you know how).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google? See http://cfaj.freeshell.org/google/

 

[John_H]

One of the nicest approaches I've seen can be found here:

http://direct.xilinx.com/bvdocs/appnotes/xapp029.pdf

Once you figure out how it works, it's quite elegant.

 

[Jim Thompson]

How to convert a 10bit digitial signal to three groups of BCD?

For example, the value of 10bit digitial is 789 in decimal.

I would like to ask how to take 7, 8, 9 away and convert each digi to BCD?

p.s. BCD is needed to display a 7-segment display via "BCD to 7-segment
display converter" 74LS48

I am going to use BASIC with Atmel AT90S8535 to do the task.

Thank you very much

Here's a nice page on how to do it with combinational logic...

http://www.engr.udayton.edu/faculty/jloomis/ece314/notes/devices/binary_to_BCD/bin_to_BCD.html

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

Old Latin teachers never die...they just decline

 

[sommes]

Thank you guys...I've got the idea...thanks a lot

 

[Marte Schwarz]

How to convert a 10bit digitial signal to three groups of BCD?

I am going to use BASIC with Atmel AT90S8535 to do the task.

well, Convert the Integer to ascii-string and then take each char and make a
Case-Construckt to a other char that transforms your BCD direct to
7-segment-code. Then you can use one port for 7-segment and 2 additional
portpins for multiplexing. Only a few rows of software.

Marte

 

[Ken Smith]

Divide your number by 10. The remainder is the ones value in BCD.

Divide the quotient by 10. The remainder is the tens value in BCD.

Divide the new quotient by 10. The remainder is the hundreds value in BCD.

The final quotient is either 1 or 0 if you really started from 10 bits.
It is the thousands value.

If you don't have a divide but do know how to add BCD values:

Consider your binary number to be all to the right of the binary point.

X = your number
Y = zero
Loop 10 times:
Y = Y + Y
decimal adjust Y ; ie make it a BCD add
X = X + X ; Shift the MSB above the "binary point"
if Y>=1024 then ; thats 2^10
Y = Y + 1 ; Put the bit in the bottom of Y
end if
end loop

 

[Rich Grise]

How to convert a 10bit digitial signal to three groups of BCD?

For example, the value of 10bit digitial is 789 in decimal.

I would like to ask how to take 7, 8, 9 away and convert each digi to BCD?

p.s. BCD is needed to display a 7-segment display via "BCD to 7-segment
display converter" 74LS48

I am going to use BASIC with Atmel AT90S8535 to do the task.

Thank you very much

2X 1024 x 8 PROMs with a look-up table. (can an Atmel do a LUT? I'm
pretty sure that doing an LUT with a PIC is a real PITA, if it can be
done at all.)

Or, since you have BASIC, you could do the repeated mod 10/divide by 10
loop, as Tim Wescott suggested. It'd be nice if high-level languages had a
facility to do an integer divide and get both the quotent and remainder
back in one instruction.

Cheers!
Rich

 

[colin]

---
The brute force way to do it is to increment a 4 digit BCD counter
then to decrement the 10 bit binary value, sequentially and
repeatedly until the binary value gets to zero, at which time the
BCD counter will have the data encoded properly.

this means you have to count up to 2^10

An improvement to this method would be to start with the most significant
decimal digit,
ie while (number is > 1000) sub 1000 from number and inc 4th digit
while (number is > 100) sub 100 from number and inc 3rd digit
etc...

then you only have to count up to 36

if you have a lot of digits you could use a digit index and a variabvle to
hold the 1000/100/10 value etc.

Colin =^.^=

 

[Ken Smith]

2X 1024 x 8 PROMs with a look-up table. (can an Atmel do a LUT? I'm
pretty sure that doing an LUT with a PIC is a real PITA, if it can be
done at all.)

Make that 2X 512. The LSB doesn't have to get translated.

 

[joseph2k]

Divide your number by 10. The remainder is the ones value in BCD.

Divide the quotient by 10. The remainder is the tens value in BCD.

Divide the new quotient by 10. The remainder is the hundreds value in BCD.

The final quotient is either 1 or 0 if you really started from 10 bits.
It is the thousands value.

You can carry this procedure on indefinitely, and it is a general method
for converting from one base to another (so should you want to display
things in base 5, now you know how).

You are a nice guy Tim, but please do not do high school homework for OP
that won't do any homework themselves.