[En-Nut-Discussion] temperature senor

[Austin Schutz]

On Fri, Oct 11, 2002 at 09:00:53PM +0900, Á¶»ó¸¸ wrote:
> 
> Hi,
> 
> I would like to monitor temperature using temperature sensor with ethernut board.
> 
> I did know Max6576 or 6577 for temperature sensor.
>  
>  This chip operates in 5V.
>  
> 1) Where I can connect sensor output  with mega103 port?
>     (port B, D, E, F)
> 
> Sensor output(manual) is as below.
>  
> MAX 6576:square-wave output with a clock period proporationl to absolute temperature. 

	If you wanted to poll the 6576 at regular intervals to check whether
or not is is sending a signal, you could hook it up anywhere. You could
also hook it up to one of the interrupt pins and have it generate interrupts.
Either way it's up to you to track how long it has been between periods. If
you are expecting very short periods (few clock cycles) then this is probably
not a good route because you may not be able to check it fast enough.

>         6577:square-wave output with a clock frequecy proportional to absolute temperature.

	All 8051 compatible chips (like the atmegas) have counter inputs.
You hook the v-f converter, in this case the temp sensor, to a counter
input. It looks like on the atmega128 the counter pins are pd6 and pd7.
You set the appropriate counter/timer and have it generate an interrupt
when the counter overflows. If you are expecting fairly high frequencies
you could use a 16 bit counter.

	Presumably Nut/OS is using at least one counter for doing
multitasking. You should check the manual to make sure you don't use that one!

> 2) Is there any other temperature sensor for ethernut board?
>     Who can introduce to me? 

	Though I'm new here I haven't seen any mention of it in the faq or
list archives. You might try searching the web for examples of other people
attaching temperature sensors to 8051 compatible chips.

> 3) have you monitored temperature with sensor and ethernutboad?
>    (if so, tell me your experience)

	I've never done it. The answers above come from what I've seen
documented. Corrections welcome.

	Austin