BCD -> Dec

Archiver

The register data (in BCD) from a Dallas 1302 RTC,
displays nicely on a BS2 Debug screen with the
following code:

'Display RTC Time and Date
Debug Home,Dec Hours.HighNib,Dec Hours.LowNib,":"
Debug Dec Minutes.HighNib, Dec Minutes.LowNib,":"
Debug Dec Seconds.HighNib,Dec Seconds.LowNib
Debug" ",DEC Month.HighNib,DEC Month.LowNib,"/"
Debug Dec Date.HighNib,Dec Date.LowNib,"/"
Debug Dec Year.HighNib,Dec Year.LowNib,cr

Actual example display:- 11:09:25 04/11/03


However, when I try to convert the BCD data in the
"Seconds" byte to Decimal so that I can use its
actual decimal value in conditional statements to
time specific actions, the results are unexpected.

The code used to convert the BCD data in the
"Seconds" byte to decimal is as follows:

Secs_In_Dec=((Seconds&$F0)>>4*10)+(Seconds&$0F)

The result, when debugged with the following
statement:
"Debug dec Secs_In_Dec,cr"
counts in decimal to 59 and then jumps to 09, 19, 29,
up to 99. The count then carries on with 10 11,
12, up to 59.

Interestingly, when I debug in binary as follows:
"Debug bin8 Secs_In_Dec,cr" I get what one would
expect: 00000000 then 00000001 as the Main Debug
screen shows the seconds count going from 59 to 00

I am overlooking something fundamental here but
cannot figure out what it is.

I would welcome illumination...

Sean

Archiver

>The register data (in BCD) from a Dallas 1302 RTC,
>displays nicely on a BS2 Debug screen with the
>following code:
>
>'Display RTC Time and Date
>Debug Home,Dec Hours.HighNib,Dec Hours.LowNib,":"
>Debug Dec Minutes.HighNib, Dec Minutes.LowNib,":"


You can do that more easily with
Debug hex2 Minutes,":"

etc. BCD and HEX are identical for numbers using only digits 0--9.


>Debug Dec Seconds.HighNib,Dec Seconds.LowNib
>Debug" ",DEC Month.HighNib,DEC Month.LowNib,"/"
>Debug Dec Date.HighNib,Dec Date.LowNib,"/"
>Debug Dec Year.HighNib,Dec Year.LowNib,cr
>
>Actual example display:- 11:09:25 04/11/03
>
>
>However, when I try to convert the BCD data in the
>"Seconds" byte to Decimal so that I can use its
>actual decimal value in conditional statements to
>time specific actions, the results are unexpected.
>
>The code used to convert the BCD data in the
>"Seconds" byte to decimal is as follows:
>
>Secs_In_Dec=((Seconds&$F0)>>4*10)+(Seconds&$0F)

That looks okay, but you can also use this..
Secs_In_Dec = Seconds.nib1 * 10 + Seconds.nib0


>
>The result, when debugged with the following
>statement:
> "Debug dec Secs_In_Dec,cr"
>counts in decimal to 59 and then jumps to 09, 19, 29,
>up to 99. The count then carries on with 10 11,
>12, up to 59.
>
>Interestingly, when I debug in binary as follows:
>"Debug bin8 Secs_In_Dec,cr" I get what one would
>expect: 00000000 then 00000001 as the Main Debug
>screen shows the seconds count going from 59 to 00

You need to use DEC2, not DEC. What you are seeing is the ghost of
the 9 left on the screen from the "59", as the Stamp DEC sends out
single digits "0", "1" ...

-- Tracy



>
>I am overlooking something fundamental here but
>cannot figure out what it is.
>
>I would welcome illumination...
>
>Sean

Archiver

Tracy
Thank you .
It works perfectly now.
I am very grateful for your help.
Sean

---

Original Message

---

From: "Tracy Allen" <tracy@e...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, April 11, 2003 12:49 PM
Subject: Re: [noparse][[/noparse]basicstamps] BCD -> Dec


| >The register data (in BCD) from a Dallas 1302 RTC,
| >displays nicely on a BS2 Debug screen with the
| >following code:
| >
| >'Display RTC Time and Date
| >Debug Home,Dec Hours.HighNib,Dec Hours.LowNib,":"
| >Debug Dec Minutes.HighNib, Dec Minutes.LowNib,":"
|
|
| You can do that more easily with
| Debug hex2 Minutes,":"
|
| etc. BCD and HEX are identical for numbers using
only digits 0--9.
|
|
| >Debug Dec Seconds.HighNib,Dec Seconds.LowNib
| >Debug" ",DEC Month.HighNib,DEC Month.LowNib,"/"
| >Debug Dec Date.HighNib,Dec Date.LowNib,"/"
| >Debug Dec Year.HighNib,Dec Year.LowNib,cr
| >
| >Actual example display:- 11:09:25 04/11/03
| >
| >
| >However, when I try to convert the BCD data in the
| >"Seconds" byte to Decimal so that I can use its
| >actual decimal value in conditional statements to
| >time specific actions, the results are unexpected.
| >
| >The code used to convert the BCD data in the
| >"Seconds" byte to decimal is as follows:
| >
| >Secs_In_Dec=((Seconds&$F0)>>4*10)+(Seconds&$0F)
|
| That looks okay, but you can also use this..
| Secs_In_Dec = Seconds.nib1 * 10 + Seconds.nib0
|
|
| >
| >The result, when debugged with the following
| >statement:
| > "Debug dec Secs_In_Dec,cr"
| >counts in decimal to 59 and then jumps to 09, 19,
29,
| >up to 99. The count then carries on with 10 11,
| >12, up to 59.
| >
| >Interestingly, when I debug in binary as follows:
| >"Debug bin8 Secs_In_Dec,cr" I get what one would
| >expect: 00000000 then 00000001 as the Main Debug
| >screen shows the seconds count going from 59 to 00
|
| You need to use DEC2, not DEC. What you are seeing
is the ghost of
| the 9 left on the screen from the "59", as the Stamp
DEC sends out
| single digits "0", "1" ...
|
| -- Tracy
|
|
|
| >
| >I am overlooking something fundamental here but
| >cannot figure out what it is.
| >
| >I would welcome illumination...
| >
| >Sean
|
|
| 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/
|
|