On Fri, 21 Jul 2000, Kosmerchock, Steve wrote:

> I am trying to interface the DS1620 digital thermometer
> with a PIC16F873. My question is about the CONFIG register
> of the DS1620. If I put the DS1620 in continous mode (1SHOT=0),
> will monitoring the DONE bit tell me when the conversion is done?
> Since it is in continous mode, won't it always be 0? If monitoring
> the DONE bit won't work in continous mode, how about waiting the
> maximum amount of time it takes to complete a conversion (1s) and
> then reading the data? Any thoughts would be greatly appreciated.
> Thanks in advance!!

Steve,

If you've got the 1620 in continuous mode, you can read the temperature
any time.  You'll get the value of the last completed conversion, which
remains in the register until a new one is done.

I put mine in 1-shot mode and watch the DONE bit.  Conversion is really
quick, and the 1620 uses *very* little current when it's not converting.
If you're on battery power, it would be worth the extra few words of code
to do it in 1-shot mode.  I've never seen the thing take anywhere NEAR 1
second to do a conversion -- I stuck an LED on my thermometer project to
monitor how much of the time the processor and DS1620 were out of SLEEP
mode.  It's never more than maybe a quarter of a second, most of it spent
sending serial data.  Sucker runs months on a 9V or four AA cells.

Dale
---
The most exciting phrase to hear in science, the one that heralds new
discoveries, is not "Eureka!" (I found it!) but "That's funny ..."
                -- Isaac Asimov

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]: PIC only [EE]: engineering [OT]: off topic [AD]: advertisements