We’re expanding our range of expand clicks with Expand 3, a click which can be expanded with more of its kind.
Expand 3 click carries DS2408, an 8-channel programmable I/O expander with a 1-Wire interface (while the first two Expand clicks use SPI and I2C, in that order).
The distinguishing feature of this particular port expander is that you can take a bunch of them and connect them into a sort of daisy chain. Each DS2408 IC has a factory-lasered 64-bit registration number, and because of how the standard Dallas Semiconductor 1-Wire protocol works, you can connect multiple Expand 3 clicks to the same data line, with each one having a unique ID. The three additional pins on righthand edge of the board are just for that.
The communication with the target board MCU is done either through OW0 or OW1 pins (which are in place of the default mikroBUS™ AN and PWM pins). To specify the exact one, solder the onboard jumper in the appropriate position.
The Libstock example shows how it all works. See the details on the product page.