DS1302 Help

Archiver

I am trying to understand the sample code given by Parallax for the
DS1302 IC, the problem is, I cannot understand how the program works.

All I want the DS1302 and the BS 2 is,

1. Program the current time to the DS1302.
2. Make the BS2 read the time on the DS1302.

Can some one help.

Thank you very much.

Archiver

Does anyone know if this code for the DS1302 will work with a DS1215?

thanks,

leroy

chris01@t... wrote:
>
> It's not as difficult as it looks. Look at Peter Anderson's site for a nice
> commented tutorial. Try www.phanderson.com/stamp/ds1302_des.html which is
> much clearer with more notations that make sense.
> I struggled with this for a while only to realise that that it's all about
> juggling DIR of the I/O and the output state of /RST.
> The basics are:
> 1. Put the I/O in the appropriate state while the serial clock line is low.
> 2. Bring /RST high and start writing a command to the clock via shiftout
> with $80, LSB1st. Your first command will probably be to clear the write
> protect bit. Bring the /RST line low to end the write.
> 3. Read the starting time that you have previously put in the Stamp's EEPROM
> (data stmt), byte by byte. If you're only using HH:MM:SS you'll only need 3
> bytes. This works well by setting I/O direction again then using a shiftout,
> LSB1st inside a for/next loop - for each byte.
> 4. Set the write protect bit
> 5. Read and display your time by making I/O output, bringing /RST high
> again, then shifting out a command byte for READ, changing I/O to in, then
> finally shiftiing in a time value byte by byte. You'll need to do this
> sequentially for the HH, MM & SS bytes. Display using debug to screen or
> serout to an LCD after each byte. Use the HEX2 modifier to convert the BCD
> to something you'll recognize as time.
>
> As long as you remember that the /RST line has to be high for the chip to do
> anything, and that you have separate commands (I think they're $80 & $81 for
> write & read) and remember that you have write protect bit to deal with, the
> rest will just use your regular old basic programming skills that you have
> used many times. This is a great chip that is easy to work with once you
> become accustomed to this method. Along with the clock function, it has
> another 31 bytes of RAM you can write to and read from with the same
> interface which more than doubles the BS2's RAM as a bonus.
>
> Chris
>
> I am trying to understand the sample code given by Parallax for the
> DS1302 IC, the problem is, I cannot understand how the program works.
>
> All I want the DS1302 and the BS 2 is,
>
> 1. Program the current time to the DS1302.
> 2. Make the BS2 read the time on the DS1302.
>
> Can some one help.
>
> Thank you very much.
>
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Archiver

It's not as difficult as it looks. Look at Peter Anderson's site for a nice
commented tutorial. Try www.phanderson.com/stamp/ds1302_des.html which is
much clearer with more notations that make sense.
I struggled with this for a while only to realise that that it's all about
juggling DIR of the I/O and the output state of /RST.
The basics are:
1. Put the I/O in the appropriate state while the serial clock line is low.
2. Bring /RST high and start writing a command to the clock via shiftout
with $80, LSB1st. Your first command will probably be to clear the write
protect bit. Bring the /RST line low to end the write.
3. Read the starting time that you have previously put in the Stamp's EEPROM
(data stmt), byte by byte. If you're only using HH:MM:SS you'll only need 3
bytes. This works well by setting I/O direction again then using a shiftout,
LSB1st inside a for/next loop - for each byte.
4. Set the write protect bit
5. Read and display your time by making I/O output, bringing /RST high
again, then shifting out a command byte for READ, changing I/O to in, then
finally shiftiing in a time value byte by byte. You'll need to do this
sequentially for the HH, MM & SS bytes. Display using debug to screen or
serout to an LCD after each byte. Use the HEX2 modifier to convert the BCD
to something you'll recognize as time.

As long as you remember that the /RST line has to be high for the chip to do
anything, and that you have separate commands (I think they're $80 & $81 for
write & read) and remember that you have write protect bit to deal with, the
rest will just use your regular old basic programming skills that you have
used many times. This is a great chip that is easy to work with once you
become accustomed to this method. Along with the clock function, it has
another 31 bytes of RAM you can write to and read from with the same
interface which more than doubles the BS2's RAM as a bonus.

Chris



I am trying to understand the sample code given by Parallax for the
DS1302 IC, the problem is, I cannot understand how the program works.

All I want the DS1302 and the BS 2 is,

1. Program the current time to the DS1302.
2. Make the BS2 read the time on the DS1302.

Can some one help.

Thank you very much.


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/