I would use a single pin for communication to the host with some variant of the one-wire protocol used by iButtons.
It is simple, elegant, and relatively insensitive to timing. Ken On 12/04/2010 04:30 AM, Erik Christiansen wrote: > On Fri, Dec 03, 2010 at 07:54:57PM -0800, Kirk Wallace wrote: > >> I really had no idea if the memory would be enough. I would have worked >> on it until I went blind in one eye. >> > Oh, it's enough for what you want to do now. But ISTR a home switch + > index filter, on the other thread. It can do that too, if pins can be > found. But then there's the extra functionality we just have to have, > when we're nearly finished. ;-) > > >> In looking for something else (small h-bridge) I found this (and >> ordered): >> http://www.sparkfun.com/products/9147 >> >> There is even some code to use as a reference: >> http://www.sparkfun.com/Code/AVR-Stick_v12.zip >> > Ah, they use the USB frame timing to calibrate the on-board RC > oscillator. > > I saw USB transmit code, but nothing for receive (i.e. for setting > watchdog timing.) Ah, your last site has projects involving USB output. > > >> http://www.obdev.at/products/vusb/projects.html >> > The "small H-bridge" design I spotted there is another very low power > example, using the L293D. I'd at the very least put some DPAK FETs on a > PCB, instead. I'm not sure I'd trust the shoot-through provisions of one > of those amateur designs. If not using half-bridge drivers with > dead-time, the ATtiny26's timer1 has complementary outputs with > dead-time fixed at one prescaler clock interval. > > However, if you want to do motor PID, then a reasonable swag of the 1k > instruction space is eaten. Incidentally, the ATmega8 (used the same > design) is old. The ATmega48 is a scalable replacement. > > >> I feel a project cascade coming on. >> > The trouble escalates when you succumb do doing "just one more design, > with just one more layout" to economise on the shipping from the cheap > PCB places in Asia. :-) > > Erik > > ------------------------------------------------------------------------------ > What happens now with your Lotus Notes apps - do you make another costly > upgrade, or settle for being marooned without product support? Time to move > off Lotus Notes and onto the cloud with Force.com, apps are easier to build, > use, and manage than apps on traditional platforms. Sign up for the Lotus > Notes Migration Kit to learn more. http://p.sf.net/sfu/salesforce-d2d > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ What happens now with your Lotus Notes apps - do you make another costly upgrade, or settle for being marooned without product support? Time to move off Lotus Notes and onto the cloud with Force.com, apps are easier to build, use, and manage than apps on traditional platforms. Sign up for the Lotus Notes Migration Kit to learn more. http://p.sf.net/sfu/salesforce-d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
