• September 24, 2023

NABU PC Will get CPU Improve, Emulates A TRS-80

The NABU PC led to a bit of of a buzz within the retrocomputing neighborhood some time again. In spite of everything, it doesn’t occur continuously that a large batch of brand-new computer systems from the Eighties all of sudden turns into to be had on eBay. Out of the field, the pc itself isn’t that helpful: with out a inner garage, or any software device in any respect, it could in point of fact handiest function a bare-bones construction platform. However since its {hardware} is fairly very similar to that of alternative fresh house computer systems, emulating a type of shouldn’t be too tough, which is strictly what [Ted Fried] did: he controlled to show his NABU right into a TRS-80 clone by way of the use of his MCLZ8 CPU emulator.

The MCLZ8 is principally an 800 MHz Teensy CPU with an adapter board that permits it to be plugged right into a Z80 socket. It emulates the Z80 CPU in real-time, nevertheless it additionally holds the TRS-80 ROM and plays real-time translation between peripherals. At the enter aspect, it reads out the ASCII characters coming in from the NABU’s 8251A UART and shops them within the digital TRS-80’s keyboard buffer. At the output aspect, it transfers the TRS-80’s video knowledge to the NABU’s TMS9918 video chip.

Click on via the damage for extra!

The motherboard of a NABU PC with a Teensy-based CPU upgradeOne downside [Ted] bumped into used to be a distinction in display answer: the NABU has a 40×24 persona show, whilst the TRS-80 generates a 64×16 persona symbol. [Ted] solved the vertical distinction by way of merely preserving the NABU emblem at the display always, and determined to simply forget about the 24 characters that drop off the precise aspect – it’s no longer a large factor for a standard BASIC program anyway.

The repurposed NABU may not be a really perfect TRS-80 clone, however that’s no longer the purpose: it displays how simply the NABU’s {hardware} may also be reprogrammed to do different issues. For instance, [Ted] has already began paintings on a brand new challenge that doesn’t emulate the Z80, however as an alternative runs code immediately at the Teensy’s ARM A9 processor. As chances are you’ll consider, this provides the NABU a number of orders of magnitude extra processing energy, even if the sensible use of that is restricted since the CPU nonetheless has to stay up for the NABU’s gradual knowledge bus and show chip. [Ted] explains the setup and runs a couple of spectacular demos within the video embedded underneath.

[Ted]’s NABU experiments are an excellent instance of the Teensy board’s flexibility: we’ve already observed the way it can emulate a Z80 in addition to an 8088. We’re additionally curious to peer what others will broaden with the NABU’s {hardware}if they are able to nonetheless purchase it, in fact.