terom@62: 
terom@62: ## Specs:
terom@62: 
terom@40: * 250 kHz clock
terom@40:     * 250000 bits / s
terom@40:     * 4µs / bit
terom@40: * idle line = high (transmitter/master drives line high)
terom@40: 
terom@62: ## Pinout
terom@40: 
terom@62:     1       0       GND
terom@62:     2       -       B
terom@62:     3       +       A
terom@62: 
terom@62: ## Protocol
terom@40: 
terom@40: * paket format
terom@40:     * break
terom@40:     * mark (MAB)
terom@40:     * 2-512 frames
terom@40:         * frame 0 = start code = 0x00
terom@40:         * frame N = channel N = 0-255
terom@40:         * 1 start bit, 8 data bits, 2 stop bits, no parity
terom@40:         * mark (MTBF)
terom@40:     * mark (MTAP)
terom@40: 
terom@40: * break
terom@40:     * syncs start of DMX packet
terom@40:     * >= 22 low bits (88 µs)
terom@40:     * up to 1s
terom@40:     * recommended 25 - 30 low bits
terom@40: 
terom@40: * mark after break (MAB)
terom@40:     * immediately follows the break
terom@40:     * high mark of > 2 bits (8µs)
terom@40:     * up to 1s
terom@40:     * recommended 3 high bits
terom@40: 
terom@40: * (channel frames)
terom@40:     * first frame is start code (SC)
terom@40:         * data value = 0x00 signifies dimmer data
terom@40: 
terom@40:     * 11 bits / frame
terom@40:         * 1 low bit (start bit)
terom@40:         * 8 data bits (0-255)
terom@40:         * 2 high bits (stop bits)
terom@40:  
terom@40:     * mark time between frames (MTBF)
terom@40:         * idle time between frames; line kept high
terom@40:         * can be as short as desired
terom@40: 
terom@40:     * between 1 and 512 sequential frames
terom@40: 
terom@40: * mark time between packets (MTBP)
terom@40:     * after the last frame's stop bits
terom@40:     * same as MTBF
terom@40:     * idle time between packets; line kept high
terom@40:     * can be as short as desired
terom@40: 
terom@40: