1.4 KiB
v2
instead of an edge plug, the monitor connector is also a receptacle. this prevents the firewall from sticking out of the monitor too much, particularly when installed in tight spaces. it also allows to place the HDMI firewall inline even if you don't have access to the monitor's HDMI port. finally it also allows the board to be manufactured more easily.
the programmer is now included in the firewall. this offers very easy copy of the EDID data. no need to use complex linux commands or stand-alone separate programmer. the programmer uses the embedded EEPROM and acts as I²C slave.
a DIP switch allows to selectively block or forward interfaces.
v1
this version comes as dongle, which can directly be plugged in the monitor. the impedance and length of the differential signal pairs are properly taken care of. a breakable tab replaces the WP switch. pads are still present to override the disabled WP and 5V.
the shield is not connected to ground, which causes EEPROM read errors with cheap HDMI cables skimping on the ground wire (pin 17). the workaround is to scratch the solder mask near one of the HDMI receptacle shell tab and solder it.
v0
first working version.
based on the design of the original research. the HDMI connectors are on opposite sides of the board to make the routing easy (the differential signals are straight lines). the impedance does not seem to by optimal, leading to EMF leakage (reported by the original researchers).