Hysteresis on dsPIC ports?
in [Design]
|
From: WangoTango on 27 Jan 2010 18:50 In article <ZR18n.147895$oC1.77725(a)en-nntp-01.dc1.easynews.com>, zapwireDASHgroups(a)yahoo.com says... > "WangoTango" <Asgard24(a)mindspring.com> wrote in message > news:MPG.25ca7071767c861498ae89(a)news.east.earthlink.net... > > Yep, turn on the PUT, the WDT, the BOR, and you have a pretty damn good > > chance of powering up in a known state. Turn on the OSC fail interrupt > > and you are really cooking with gas. > > Will PICs do "failover" to an internal RC clock if the xtal (or other external > clock input) doesn't fire up? I used some MSP430s a large handful of years > ago that did that, and thought it was pretty slick. Depends on the flavor, but most of the new units have the option and it will jump to an ISR to let you make timing adjustments or fail gracefully/shut down. I usually turn it on to let me set the IO in a known state and then report the error, if possible. > > We use some Atmel AVRs at work that have this "tacked on" ability to use a > 32kHz crystals as a very-low-power oscillator for a timer (generally to wake > the processor up from sleep). It works, but it's nowhere near as elegant as > what you could do with MSP430s. > > ---Joel Microchip has come a long way in the past few years. They have even done some changes to their crazy cores to allow high(er) level languages to do things like string handling a bit cleaner. I was a BIG Motorola/Freescale fan, but they don't like to make new parts fit into old sockets. Microchip likes to stick with a pin out and just ups the performance of the guts. I know you can plug a 16C73, 16C76, 16F876(A), 18F242, 18F252, 18F2420, and 18F2520 all into the same socket and get more and more levels of performance. So, when they disco a part you just get the latest greatest and do a recompile, if needed, and go on your way. |