uC favorites?

[Spehro Pefhany]

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 écrit 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

 

[Fred Bartoli]

"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> a écrit 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.