github.com/ozzyrob/Linuxcnc-FPGA/tree/main
Spartan 6 based project.
Supports Linuxcnc-RIO either with direct spi connection or with the UDP Bridge.
Based on a common Spartan 6 dev board available via aliexpress.
Easily assembled, mostly through hole components only SMD parts are a couple of chips.
Modified 7c81 firmware spi mode
EPP interface also can be implemented.
Have experimented with firmware that supports upto 60 i/o (compared to 57 with the 7c81) requires a dedicated driver, easy enough to implement based on the 7i90 driver for EPP interface.
Easily interfaces to your basic Parallel Port breakout board, up to 3.
using a Aliexpress RS-422 interface baords allows SSerial connection, tested with a 7i73 device.
If anyone in Australia is interested I have a few unpopulated pcbs available.
