Changes

The purpose of the power bus to supply power to the entirety of the flight-stack. It does this using high-current rated pins, ultimately deriving their power from the BMS. At the time of writing, the active BMS is Biscuit, and the following will be written with the Biscuit specifications.

The purpose of the power bus to supply power to the entirety of the flight-stack. It does this using high-current rated pins, ultimately deriving their power from the BMS. At the time of writing, the active BMS is Biscuit, and the following will be written with the Biscuit specifications.

The power bus provides a +5V supply, with a flight-stack current limit of 4A -- this voltage should be used for devices that specifically require 5 volts (such as Iridium), or in many cases for more localized and low-noise voltage regulation on individual boards (i.e. LDO'ing the 5V to 3.3V for a local Teensy).  

The power bus provides a +5V supply, with a flight-stack current limit of 4A -- this voltage should be used for devices that specifically require 5 volts (such as Iridium), or in many cases for more localized and low-noise voltage regulation on individual boards (i.e. LDO'ing the 5V to 3.3V for a local Teensy).  

The power bus also provides two utility regulators -- 1.8V for specific 1.8V applications for some specialty IC's (250 mA limit), and an adjustable buck that regulates to a voltage between 0V and 5V, as dictated by the Avionics. The Avionics is solely responsible for regulating the adjustable voltage, using the VA_PWM pin on the data bus -- if your board necessitates an adjustable voltage, it must request the adjustment via the avionics, which will either accept or deny the request, and act accordingly.  

The power bus also provides two utility regulators -- 1.8V for specific 1.8V applications for some specialty IC's (250 mA limit), and an adjustable buck that regulates to a voltage between 0V and 5V, as dictated by the Avionics. The Avionics is solely responsible for regulating the adjustable voltage, using the VA_PWM pin on the data bus -- if your board necessitates an adjustable voltage, it must request the adjustment via the avionics, which will either accept or deny the request, and act accordingly.  

Lastly, the power bus provides two nodes for common ground, which must be implemented to common-ground a board to the BMS/flight-stack.  

Lastly, the power bus provides two nodes for common ground, which must be implemented to common-ground a board to the BMS/flight-stack.

=== Data Bus ===

=== Data Bus ===