Receiver hardware for IR beam (red eye)?

[Tinue]

Interesting; Emulating a module seems rather complex. I guess you need to emulate the ROM chip itself, and all of the I/O that is going on. I wonder how this fits into these tiny PIOs. Just emulating the ROM needs to read the address lines, send the address up to the C-code, read back the ROM value from C-Code, and then clock it out to the data bus. But then you said that you have little room left for the Red Eye handler.

As for my code: I did the Red Eye sender first, and was not yet comprehending the half bits. This is why my C-code sends 54 bits to the state machine, and the state machine simply loops through the bits, bursts on a one, pauses on a zero. Also, just because I started this way, I use two state machines: One does the actual burst, and gets triggered by the other one. In total they need 10 instructions.

My receiver came afterwards, and is more efficient. It can communicate an entire byte in 14 2-bit words up to the C-code. It needs 13 instructions if there is a burst detector attached, and 7 more if it needs to analyze the carrier frequency itself. I just about fill the capacity of one PIO with using 4 state machines and 30 instructions.