Forums

uC favorites?

Started by Bob Stephens April 27, 2004
On Thu, 29 Apr 2004 16:29:03 +0200, the renowned "Fred Bartoli"
<fred._canxxxel_this_bartoli@RemoveThatAlso_free.fr_AndThisToo> wrote:

> >"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> a &#2013265929;crit dans le message >news: s7e090hmiiu7kj8aup5debfmhoc5o6u27f@4ax.com... >> On Thu, 29 Apr 2004 10:56:05 +1200, the renowned Jim Granville >> <no.spam@designtools.co.nz> wrote: >> > >> >Vref stability is a matter for the fine print. ALL Vrefs will differ >> >from unit to unit, and also vary over temperature. >> > The key point is, by how much ? >> > >> >[They quote 2.44V, or 2.43V Typical as Vref, so 'about 2.4401' does not >> >sound too terrible ? ] >> > >> > Their spec also says typ 15ppm/'C tempco. >> >That's not the very best, but Maxim sell plenty of Vrefs worse than >> >that. Remember this is an ON-CHIP, Vref. >> >> An on-chip Vref has the disadvantage that it is at the die temperature >> for the micro. No big deal if the micro is running at a couple of mA >> and not switching much, but if it is running hot you can get >> objectionable (perhaps on cosmetic grounds) drift during warm-up. >> > > >If you have a power hungry uC and plenty of unused CPU time then you have >die temperature control for (almost) free. >Fred.
Assuming you have an on-chip temperature sensor, just sleep the CPU to maintain a constant die temperature? Or perhaps load some outputs heavily? How to turn a complex mixed-signal microcontroller into a LM199? Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> a &#2013265929;crit dans le message
news: ua5290dg7186hr5091lj2um8h60fmbr9ae@4ax.com...
> > >If you have a power hungry uC and plenty of unused CPU time then you have > >die temperature control for (almost) free. > >Fred. > > Assuming you have an on-chip temperature sensor, just sleep the CPU to > maintain a constant die temperature? Or perhaps load some outputs > heavily? How to turn a complex mixed-signal microcontroller into a > LM199? > >
One have plenty of temperature sensors on a uC. Don't they have lots of available inputs ? (just use the clamping diodes). That way you could even have temperature mapping of the die, well at least at the periphery. Taking it a bit further then you can fine tune the code (which die area gets to switch) so as to draw an IR image on the die. Oh yes, that *slow* scan IR TV could well be as entertaining as ordinary programmes. Thanks, Fred.