Port
From veswiki
The VES has four usable 8-bit data ports in the console, port 0 and 1 that are in the 3850 CPU and port 4 and 5 on one of the 3851 Program Storage Units.
Port 0
0 TIME console button
1 MODE console button
2 HOLD console button
3 START console button
4 - not connected -
5 ARM (to graphics)
6 Enable in-signal from controllers
7 - not connected -
Port 1