Need some advice.

[sayzer]

Why not just skip the busy state of the temp conversation??

If the temp conversation is in progress, do not wait, just pass it.

[Acetronics2]

Hi, Sayzer


WHILE temp conversion ...

REGULATOR loops ...

of course !

just have to verify that the Process time. constant is 10 times or more the sensor time constant ...

If you want it to look at, I committed sometimes ago a DS 1820 temp regulator : a R/C servo drives air flow section to cool some heating stuff ...

Let's say it is intended to control the air flaps of a model "Corsair F4U " engine cowling ...

Alain

[cphillips82]

thanks for you suggestion acetronics but burst will not work for me, I really need to regulate via dimming an incandescent bulb so it is not switching on and off all the time annoying eyes. I have checked only sending a

OWOut DQ, 1, [$CC, $44]       ' Start temperature conversion

yet this still makes a flicker which tells me that my interupt is not being seen while sending this message. does anybody know or can work out how long this command takes so I may be able to time when to send it?

[Acetronics2]

when sending this line ... it just tell the DS to do it's measurement.

what takes time is wait for the DATA line to come back high ...

you can do other things just past this line ... PbP doesn't poll the line or insert a Pause "by itself " to let you do what you want during the conversion time.

some MPLAB "stopwatch" to justify it.

Owout $CC,$44 ... 473 µs @ 4 Mhz
$CC,$BE ... id !!!
Owin.. ... 1140 µs ( read result )


will be difficult not to see "something" happens when "talking" with the DS ...

I remember having soldered a an Incubator regulator with a single TDA 1023 ... which has a voltage setpoint input.
The pic could make the temp measurement, drive alarms (?), convert digital setpoint ( a simple R/2R ladder as a DAC will be enough ) to an analog setpoint , and drive a cute viewing LCD display panel ...

can of course being done with a Pic, but some trickery will be compulsory to place the different DS commands in the cycle time ...

Alain

[cphillips82]

I love IT! This chip rocks, so an input voltage = output duty cycle. Is that right in simple terms? I'm going to study this data sheet. thanks for the suggestion!
Clint

[Acetronics2]

Hi,

You also may download the TCA 785 or TDA 1185 Datasheets ... same kind of chips !

Alain

PS : Do not forget the Lilly -of-the-valley !!!

[cphillips82]

i'm going to take the approach of using an 16f88 with a tca785 using the onboard pwm so there are no timing issues while keeping the ds1820. what is the lilly of the vally?