Eight fuses that can light blackpowder charges
The pyro module consists of eight connectors which can each light a blackpowder charge. Each connector is controlled by a mosfet, and if the mosfet allows current to flow through the connector, then the blackpowder charge is ignited.
The core module controls this by sending I2C messages over the I2C0 bus to the I/O expander module. The I/O expander module connects to eight mosfet drivers which drive the mosfets. The I2C messages that come to the I/O expander can tell it to set off certain blackpowder fuses.
The I/O expander also features three address bit jumpers, which can be manually connected or disconnected to change the I2C address of the I/O expander, to avoid I2C address conflicts.