I finished getting the autodetect function running, so now the chip has the basic program on it that I set out to do a few years ago. For auto detecting, I just looped through 32 times while waiting for the timer to count from 0 to 0xb000 and looked for activity on any pin. If it saw some, it was set as active by just running activeChannels |= PORTD each time. I also took my timing code and made it a little cleaner and more efficient. The entire program is around 1.5KB, though I have 16KB of total space I can use on the chip.I have been kicking around the idea of using the same chip to send out PWM as well. A simple copy of PORTD to PORTB would probably suffice for normal operation. If I come up with code for sending out pulses (which should be pretty easy), I can do things like have a mode for just holding steering controls in whatever position I left them in. As far as I know, this is one of very few chips that can read 6 RC channels (possibly more) simultaneously, which is why I developed it. Perhaps, after some more work and additional refinement, it could be something to sell, since it's currently very specific to my setup.

I'm also thinking of looking into I²C. I learned a lot working with SPI. In order to get that working, I had to program the arduino and PIC with 2 mismatched configurations and now realize the same thing probably applies to I²C. My main disappointment with SPI is the fact that it takes up not just PORTC, but also uses a pin off the middle of PORTA, rendering it quite useless for many things.

I was looking into expanding the memory for my arduino as well. It appears just popping out the ATmega168 chip, popping in an ATmega328 chip, and programming a bootloader will double it's memory minus the size of the bootloader (about 2K). I'm looking into throwing together a simple AVR programmer as well, which will be required for uploading the bootloader. I placed a sample order for a couple of ATmega328's yesterday, so hopefully those will arrive in the next few days. I looked into using an MMC card with the arduino and found a library called SDFATlib, which would allow access to files that are PC readable. However, the library takes up a considerable amount of size, so the chip upgrade will pretty much be necessary to run that.

So I guess my next steps here are to create PWM generation code, look into building an ATmega Programmer, and take one last look at I²C.