# NuXT1-MultiIO

a WIP Multi-I/O card for the NuXT 1.2 XT clone from Monotech. 

The hardware for this is licenced under the [CERN Open Hardware Licence Version 2 – Strongly Reciprocal](https://opensource.org/license/cern-ohl-s) 
in line with the original licences from open hardware projects from which this project is 
derived. 

## Features 
- a TimeKeeper - a battery-backed Real Time Clock and nonvolatile storage, cribbed from [Aitor Gómez García's](https://www.aitorgomez.net) [RTC8088](https://github.com/spark2k06/RTC8088/tree/main) project. 
- a Printer Interface, or Parallel Port - probably based off the original Printer Interface Card at this point, or possibly the IBM Serial/Parallel Card 
- two Serial ports, corresponding to COM2 and COM3 - using the 16550 UART for higher-speed links, but based either on application notes or the IBM Serial/Parallel Card. 
- one of the above Serial ports may connect directly to a RasPi Zero, either to provide a slightly more modern machine to `minicom` to, or to serve a `ppp` link for internet access. 

## Purpose 
The v1.2 NuXT is an excellent computer with just a few missing features for convenience. The NuXT v2 
has improved on this, but there is still an installed base of NuXT v1 devices that can benefit from 
a semi-modern multi-I/O solution; existing multi-I/O cards may also have features that are superfluous 
or conflict with onboard peripherals. 

I (Horst Burkhardt) determined that what I primarily needed from an expansion card was a method of network 
connectivity, (best served by a serial link), a parallel port, and that I would like a Real Time Clock. 
If I can find documentation on the original IBM XMA (Expanded Memory Adaptor) or a similar card, I would 
also be willing to add RAM on this card, in order to provide enough space for a RAMdisk. 

## Questions

### Why not Ethernet?
An 8088 or an NEC V20 with half a megabyte of memory just doesn't need ethernet. Quite frankly, a 10Mbps 
link will often work poorly on a modern Gigabit-capable switch. And I don't really relish making CAT5 
cross-over cables. 
A serial link at 115200 baud, which is roughly where a 16550 tops out, is more than fast enough to 
transfer files to an 8088. It's also a lot computationally simpler than managing an ethernet link, so 
despite the potential for higher transfer speeds from an ethernet NIC, the real-world gains are dubious. 

### Why aren't you taking advantage of $(the hot new thing)?
Because I don't care. It's not important. This device must be reliable, simple to troubleshoot, and 
most importantly, I have to understand it. 
If a new device is compelling enough, I'm happy to try and work with it, but I'm not putting my name 
on something untested and unproven. 

### Why are you like this? 
Some very clever people have tried to work that one out, and failed. For now, you're stuck with me.