Schematics for 7c81

Some update on my progress

 

using EasyEDA with available components form JLCPCB and LCSC
 

TOLX are the power to the bus switches, ~4.2V in 5V tolerant mode and
5V in 3.3V tolerant mode.

Thanks for clarifying that, can the 7c81 use all three ports and use the 2 x RS422/485 ? I think i was reading somewhere if you enable the RS422/485 then the third port is disable or cannot be used ?

There is no connection between the Parallel ports and the RS-422/485 interfaces,
however if you have a large configuration like 5ABOBx3 with 13 Stepgens, there is not
enough room for the 2 SSerial ports (though there may be room from UARTs)

The parallel ports are always usable as GPIO though, so on a 5ABOBx2 configuration
the third port can be GPIO

I think i will design the Port one as a Parallel out and port 2 as a Parallel in and use 74HCT245 as output IC's and 74LVC245 as the input IC's. As per these schematics :

 

The 74 245 are quite plentiful:
www.lcsc.com/search?q=74HCT245
www.lcsc.com/search?q=74LVC245

And then output with terminal screw that resemble my breakout board i posted.

Port 3 will i leave as through hole for later development or prototyping.

I see there are a lot of SP491 available from this supplier so i will just copy the RS-485 Schematics www.lcsc.com/search?q=SP491

how is the progress on this schematic ?