JT8255
Programmable peripheral interface compatible with Intel 8255, by Jose Tejada (aka jotego)
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JT8255 is a PPI written in Verilog, fully compatible with Intel 8255.
Architecture
Note that the design does not use clock enable signals, and due to the nature of its functionality, it is discouraged to add a clock enable.
The original chip did not have a clock signal, but was completely asynchronous. This modern version uses a clock to detect the input signal edges. It is expected that the devices connecting to this module will share the same clock signal but operate under a clock enable regime that decreases their effective frequency.