I'm fairly certain the basic UART protocols are long since public domain, but FTDI's specific implementation of it in their chip may be protected by copyright or patent; I haven't looked into the details.
https://en.wikipedia.org/wiki/Universal_asynchronous_receiver/transmitter
Invented by Gordon Bell, then of DEC, for the PDP-1. Interesting backstory.
On Thu, Feb 4, 2016 at 11:49 AM, AndyHC jarndice@gmail.com wrote:
UART - seriously - can uart chip technology still be under patent? Something seriously wrong with the patent (and copyright) systems.
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