On 10/24/2022 at 9:51 PM, neutrino said:
It's a choice that does what is possible with the existing hardware. Adding a 6551 means more PCB area and the cost of another chip.
Reading is fundamental. Adding a 6551 definitely does not mean more PCB area, because the hardware design is moving from prototype to beta release. We will find out more details when the boards come back and they do a show and tell, but we do know that one option for a serial port is an expansion card. It is conceivable that another option is a User port bridge, but it is up in the air whether there will be a motherboard User Port. We know that the Proto #2 User Port will not be available, but the shift to the MCU for the PS/2 ports implies that three GPIO and four handshake lines of VIA#1 are probably unused., and at least the possibility of bringing some VIA#1 pins out was raised as a possibility by a team member on FB.
There has been no indication that I have heard of any of the MCU pins being voltage protected and brought out as part of a User Port, so if you have a post by one of the project team members that you are referring to for that, you should perhaps post the link to that in lieu of data sheet links.