• 1800Hz, 16-bit PWM (12-bit + 4 bits dithering)
• 3-channels, almost evenly spaced phase offsets
• inverse polarity compared to WS2811 (pin high = LED on)
• UART based signalling, 38400 baud, 16 bit values, (2x 8bit uart frame/channel, little endian)
• end-of-frame is determined using a reset delay (between 1-2msec)
• no output line, led index is hard-coded in the firmware
• tested on PFS154 & PMS150C

$ ./write.sh 0 # use the first 6 bytes as pixel data

$ ./write.sh 1 # use bytes 6..11 as pixel data

$ ./read_address.sh
Address: 0

Even on one-time programmable chips, a limited number of address changes if possible:

$ ./change_address.sh 4   # this is the fourth chip in the LED strip

OTP parts like PMS150C start out with a ROM with all ones, bits can only be flipped once, from 1 to 0.

The following scheme makes it possible to update the chip's address many times:

The code reads (13 or 14 bit) opcodes at the end of the code section. opcodes where the high bits are set to 0 are skipped. The first opcode with non-zero high bits contains the address in its low byte.