linux-works
DIY: perf board port expander for PGA volume control
upper left is the LED bargraph (for debugging and cool factor). upper right is the pair of i2c connectors (one input and one feed-thru for daisy chaining). bottom right is the pcf8574 PE chip. far right is the 3x3 pin array for selecting the 3 bits (a0,a1,a2) of the PE chip.
6 bits on the PE chip are mapped to 3 chip-selects, a clock and a data line. this allows each of the 3 PGA2311 chips to be accessed with their own CE line (or logic OR them to talk to them all; like a broadcast).
building this by hand took about half a day. I like to take my time and have a neat layout, both on top of the board and below.
wire is kynar wire-wrap wire. still useful for something ;)
DIY: perf board port expander for PGA volume control
upper left is the LED bargraph (for debugging and cool factor). upper right is the pair of i2c connectors (one input and one feed-thru for daisy chaining). bottom right is the pcf8574 PE chip. far right is the 3x3 pin array for selecting the 3 bits (a0,a1,a2) of the PE chip.
6 bits on the PE chip are mapped to 3 chip-selects, a clock and a data line. this allows each of the 3 PGA2311 chips to be accessed with their own CE line (or logic OR them to talk to them all; like a broadcast).
building this by hand took about half a day. I like to take my time and have a neat layout, both on top of the board and below.
wire is kynar wire-wrap wire. still useful for something ;)