Payloads & Interfacing with External Boards
How to connect to external payloads, ADCS boards, etc...
Overview
Whether soldering a board onto the SMT slots or using an SMT header, the payload pinouts provide access to 3.3V, UART, I2C, SPI, and VBATT (via PYLD VDD).
Payload Headers
The inner pads of the "payload slots" can accommodate standard 0.1" surface-mount headers. 2 row, 18 pos. surface mount headers (male or female) work best.
Example P/Ns:
Header Pinouts
Any of the pin names pictured above can be accessed in CircuitPython using the board
object.
For example:
Using a pin as GPIO
from pycubed import cubesat import board import digitalio gpio = digitalio.DigitalInOut(board.PB16) gpio.switch_to_output() gpio.value = True # set GPIO high gpio.value = False # set GPIO low
Using I2C (SD2/SCL2)
from pycubed import cubesat import board import busio i2c2 = busio.I2C(board.SDA2,board.SCL2)
Using UART (TX2/RX2)
from pycubed import cubesat import board import busio uart2 = busio.UART(board.TX2,board.RX2) # you can also swap the pins # uart2 = busio.UART(board.RX2,board.TX2)
See 🎹Pin Muxing for more details on what pins can do what functions
Payload Board SMT Slots
Similar to the radio modules' surface mount mezzanine style, the payload board slots can accept custom PCBs soldered directly to the board. You can even span across two payload spots to accommodate larger payload designs.
Full design schematics and layout for the ADC payload board pictured above:
We've even seen groups make payload boards that span both slots, like this →