1The controls for the mux are GPIO [0,1] for source, and GPIO 2 for muting. 2 3GPIO0 GPIO1 4 0 0 TV Audio 5 1 0 FM radio 6 0 1 Line-In 7 1 1 Mono tuner bypass or CD passthru (tuner specific) 8 9GPIO 16(i believe) is tied to the IR port (if present). 10 11------------------------------------------------------------------------------------ 12 13>From the data sheet: 14 Register 24'h20004 PCI Interrupt Status 15 bit [18] IR_SMP_INT Set when 32 input samples have been collected over 16 gpio[16] pin into GP_SAMPLE register. 17 18What's missing from the data sheet: 19 20Setup 4KHz sampling rate (roughly 2x oversampled; good enough for our RC5 21compat remote) 22set register 0x35C050 to 0xa80a80 23 24enable sampling 25set register 0x35C054 to 0x5 26 27Of course, enable the IRQ bit 18 in the interrupt mask register .(and 28provide for a handler) 29 30GP_SAMPLE register is at 0x35C058 31 32Bits are then right shifted into the GP_SAMPLE register at the specified 33rate; you get an interrupt when a full DWORD is received. 34You need to recover the actual RC5 bits out of the (oversampled) IR sensor 35bits. (Hint: look for the 0/1and 1/0 crossings of the RC5 bi-phase data) An 36actual raw RC5 code will span 2-3 DWORDS, depending on the actual alignment. 37 38I'm pretty sure when no IR signal is present the receiver is always in a 39marking state(1); but stray light, etc can cause intermittent noise values 40as well. Remember, this is a free running sample of the IR receiver state 41over time, so don't assume any sample starts at any particular place. 42 43http://www.atmel.com/dyn/resources/prod_documents/doc2817.pdf 44This data sheet (google search) seems to have a lovely description of the 45RC5 basics 46 47http://www.nenya.be/beor/electronics/rc5.htm and more data 48 49http://www.ee.washington.edu/circuit_archive/text/ir_decode.txt 50and even a reference to how to decode a bi-phase data stream. 51 52http://www.xs4all.nl/~sbp/knowledge/ir/rc5.htm 53still more info 54 55