The description of the BCE reminds me a lot of the PIO in the RP2040 and 2350 microcontrollers. From the article, BCE instructions include "Transmit Data, Receive Data, Load Timeout Register, Store Status, and Wait."

To me, these correspond more or less 1:1 with PIO instructions OUT, IN, SET, INT, and WAIT. These plus PUSH, PULL (which can considered auxiliaries of IN and OUT), MOV, and JMP are all the PIO instructions. Like the BCE, it runs with completely deterministic clocking, one instruction per clock, and like the BCE there are a bunch of them (a total of 12 state machines on the 2350), though they now run totally in parallel rather than being time-multiplexed.

As a hobby project, I've lately been implementing USB (aiming for higher performance than Pico-PIO-USB, which proves that it's possible), and that's been quite fun.

I wonder to what extent they were explicitly inspired, and to what extent you just get convergent solutions when there are similar goals and constraints.