number more than 65535 again
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Hello,
Before I have got from Tracy Allen the tricks to count up to a number more
than 65535 and using MAX7219 to display it.This time I think I have
something different,in my project"Digital Weigh Scale Indicator"I have the
following equation to convert the o/p code from 16 bit A/D to grams weight
using MAX7219 with 5 digits display:
weight=ADdata** 34464 + ADdata
where ADdata is the code in 16-bit word length.
From the equation the max. reading is 65535 grams weight ,so how can I get
readings up to 99999 grams weight?
Thank You
Mohamed Refky
_________________________________________________________________
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Before I have got from Tracy Allen the tricks to count up to a number more
than 65535 and using MAX7219 to display it.This time I think I have
something different,in my project"Digital Weigh Scale Indicator"I have the
following equation to convert the o/p code from 16 bit A/D to grams weight
using MAX7219 with 5 digits display:
weight=ADdata** 34464 + ADdata
where ADdata is the code in 16-bit word length.
From the equation the max. reading is 65535 grams weight ,so how can I get
readings up to 99999 grams weight?
Thank You
Mohamed Refky
_________________________________________________________________
Chat with friends online, try MSN Messenger: http://messenger.msn.com
Comments
So, the scale has a capacity of 100000 weight units, and at full
capacity it rolls out an ADC count of 65536. So the conversion from
count to weight is
weight = ADdata * (100000/65536) = ADdata * 1.525879
which in Stampese as you say is coded as:
weight=ADdata ** 34464 + ADdata
The critical ADC value is ADdata>42949. Like this:
42949**34464+42949 = 65534
which is okay and fits in one word, but
42950**34464+42950 = 65536
overflows a word and shows up as 0 on the Stamp. It is the correct
value minus 65536. The solution is to keep track of the carry, when
the ADdata>42949. Only one bit of carry is necessary, because the
weight is <100000. Your program will have to use a a double
precision divide by ten to get the number back to the 16-bit range.
Here is example code:
' enter here with ADread, from 0 to 65535
rm var nib ' remainder for divide by 10
carry var bit ' carry bit
' now compute carry and weight modulo 65536
carry=ADdata min 42949-42949 max 1 ' 1 if ADdata>42949
weight=ADdata ** 34464 + ADdata ' modulo 65536
' now divide double precision value /10
rm = ADdata//10 +6 ' preliminary remainder
ADdata=6553+(ADdata/10)+(rm/10) ' double precision divide
rm=rm//10 ' final remainder
debug "weight=",dec4 ADdata, dec1 rm,cr
I hope that helps.
-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com
>Hello,
>Before I have got from Tracy Allen the tricks to count up to a number more
>than 65535 and using MAX7219 to display it.This time I think I have
>something different,in my project"Digital Weigh Scale Indicator"I have the
>following equation to convert the o/p code from 16 bit A/D to grams weight
>using MAX7219 with 5 digits display:
> weight=ADdata** 34464 + ADdata
>where ADdata is the code in 16-bit word length.
>
> >From the equation the max. reading is 65535 grams weight ,so how can I get
>readings up to 99999 grams weight?
>
>Thank You
>Mohamed Refky
precision divide in my last post. More background info at
<http://www.emesystems.com/BS2math6.htm#method1>
> ' enter here with ADread, from 0 to 65535
> rm var nib ' remainder for divide by 10
> carry var bit ' carry bit
> ' now compute carry and weight modulo 65536
> carry=ADdata min 42949-42949 max 1 ' 1 if ADdata>42949
> weight=ADdata ** 34464 + ADdata ' modulo 65536
> ' now divide double precision value /10
> rm = ADdata//10 +(6*carry) ' preliminary remainder
> ADdata=(6553*carry)+(ADdata/10)+(rm/10) ' double precision divide
> rm=rm//10 ' final remainder
> debug "weight=",dec4 ADdata, dec1 rm,cr
-- Tracy
I use MAX7219,so how can I display the result.
Thank You
Mohamed Refky
>From: Tracy Allen <tracy@e...>
>Reply-To: basicstamps@yahoogroups.com
>To: basicstamps@yahoogroups.com
>Subject: Re: [noparse][[/noparse]basicstamps] number more than 65535 again
>Date: Wed, 27 Feb 2002 00:31:58 -0800
>
>Oops, I forgot to roll the carry into the formula for the double
>precision divide in my last post. More background info at
><http://www.emesystems.com/BS2math6.htm#method1>
>
> > ' enter here with ADread, from 0 to 65535
> > rm var nib ' remainder for divide by 10
> > carry var bit ' carry bit
> > ' now compute carry and weight modulo 65536
> > carry=ADdata min 42949-42949 max 1 ' 1 if ADdata>42949
> > weight=ADdata ** 34464 + ADdata ' modulo 65536
> > ' now divide double precision value /10
> > rm = ADdata//10 +(6*carry) ' preliminary remainder
> > ADdata=(6553*carry)+(ADdata/10)+(rm/10) ' double precision divide
> > rm=rm//10 ' final remainder
> > debug "weight=",dec4 ADdata, dec1 rm,cr
>
> -- Tracy
>
>
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>I use MAX7219,so how can I display the result.
>
>Thank You
>Mohamed Refky
Maybe you give me the example number, then I will try to explain. I
do not want to have to look up the protocol for the MAX7219!
-- best regards
Tracy Allen
electronically monitored ecosystems
http://www.emesystems.com
mailto:tracy@e...
weight.
In calculator:
weight=ADdata**34464+ADdata
=(49152*34464)/65536+49152=75000
then the program display the result:
weight=dispVal
gosub MaxDisplay
>From: Tracy Allen <tracy@e...>
>Reply-To: basicstamps@yahoogroups.com
>To: basicstamps@yahoogroups.com
>Subject: Re: [noparse][[/noparse]basicstamps] number more than 65535 again
>Date: Thu, 28 Feb 2002 15:53:09 -0800
>
> >May I get example with a number to explain the code.
> >I use MAX7219,so how can I display the result.
> >
> >Thank You
> >Mohamed Refky
>
>Maybe you give me the example number, then I will try to explain. I
>do not want to have to look up the protocol for the MAX7219!
>
> -- best regards
> Tracy Allen
> electronically monitored ecosystems
> http://www.emesystems.com
> mailto:tracy@e...
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
>from the same email address that you subscribed. Text in the Subject and
>Body of the message will be ignored.
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
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> > >I use MAX7219,so how can I display the result.
>A code for example of 49152 from the A/D is corresponding to 75000 grams
>weight.
>In calculator:
>weight=ADdata**34464+ADdata
> =(49152*34464)/65536+49152=75000
>then the program display the result:
>weight=dispVal
>gosub MaxDisplay
Hi Mohamed,
The total weight, maximum 999999, cannot be held in one Stamp 16 bit
word. So your MaxDisplay routine will have to deal with at least one
more bit of data. In the following, as it ends up, one word holds
four digits from 0 to 9999, and an additional nib holds the last
digit, 0 to 9.
rm var nib ' remainder for divide by 10
carry var bit ' carry bit
ADdata var word ' from weight scale
j var nib ' for loop
gosub getADdata ' not shown
' returns ADdata, in general from 0 to 65535
' say ADdata=49152, weight =49152*1.5258789062=75000grams
' now compute carry and weight modulo 65536
' notes follow program listing
carry=ADdata min 42949-42949 max 1 ' Note A
weight=ADdata ** 34464 + ADdata ' Note B
' now divide double precision, weight /10
rm = weight//10 +(6*carry) ' Note C
weight=(6553*carry)+(weight/10)+(rm/10) ' Note D
rm=rm//10 ' Note E
' show the result on debug
debug "weight=",dec weight, dec1 rm,cr ' Note F
' show result on MAX7219 (untested)
low load
shiftout dpin,cpin,msbfirst,[noparse][[/noparse]9,$ff] ' Note G
high load
for j=3 to 0 ' Note H
low load
shiftout dpin,cpin, msbfirst,[noparse][[/noparse]j+2,weight dig j)]
high load
next
low load
shiftout dpin,cpin, msbfirst,[noparse][[/noparse]1,rm] ' Note I
high load
end
' Notes <mailto:tracy@o...>
' Note A: compute carry
' 49152 min 42949 = 49152
' 49152 -42949 = 6203
' 6203 max 1 = 1 = carry bit
' Note B: compute weight modulo 65536
' 49152 ** 34464 = 25848 (49152*0.5258789)
' 25848 + 49152 = 9464 Stamp loses high bit to fit word!!
' note that (75000=65536+9464)
' The total weight is now expressed in base 2^16
' as 1*65536 + 9464, the "1" is the carry bit
' Note C: preliminary remainder
' 9464//10 = 4
' 4 + (6*1) = 10
' Note
' (6553*1)+(9464/10)+(rm/10) = (6553)+(946)+(1)=7500
' 4 most significant digits of weight fit in one word
' Note E: final remainder
' 10//10 = 0
' this is the least significant digit of the weight
' Note F: show result
' Stamp holds "7500" in weight, and "0" in rm.
' prints in two chunks
' Note G:
' SPI command 9 to select the BCD mode of the MAX7219 on all
($ff) digits
' framed with load pin low, command executed when load goes high
' CAVEAT--I have not tested these MAX7219 routines.
' Note H:
' SPI loop to send 4 most significant digits to MAX7219
' sends most significant digit first to positions j+2={5,4,3,and 2}
' operator weight dig j picks off the digits one by one
' framed with load pin low, command executed when load goes high
' Note I:
' SPI command sends least significant digit rm to MAX7219
' puts it in digit 1 position on the display
' framed with load pin low, command executed when load goes high
That was fun! I hope I didn't slip too many typos in there.
-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com