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SD: Report the switches in binary format

FAST Serial Protocol: Overview & First Steps

This documentation section is about the FAST Serial Protocol (FSP) commands, which are the low-level commands a host computer sends to a FAST board. Most FAST Pinball makers do not need to know about these details, since the pinball game framework (such as the Mission Pinball Framework) handles this communication for you.

If you're writing your own game framework, we have a series of programming guides. Also, be sure to read the overview of how FSP works and how to connect first.

Get the raw hardware debounced switch state for every switch, in binary format. This command is similar to SA:, except with binary results instead of ASCII.

The SD: command response includes the physical state of each switch. If you configured the switch to report inverted, that only affects the /N -N or /L -L messages, not this SD: output.




There is no <CR> sent on the end of this response



Response: (because this is binary it will often contain ASCII characters which will not be printable)

SD: #/^ ! +

Documentation Feedback? Requests? Confused?

Hi! I'm Brian, and I'm responsible for the documentation at FAST Pinball. If you have any feedback, requests, corrections, ideas, or any other thoughts about the docs, please let me know!

You can email me at I maintain this site in my spare time, so there might be a week or so delay if you email me.

If you have a more pressing need, reach out to us via Slack, or email Aaron Davis.


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