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

The NABU PC brought about a little bit of a buzz within the retrocomputing group some time again. In spite of everything, it doesn’t occur usually that an enormous batch of brand-new computer systems from the Eighties out of the blue turns into out there on eBay. Out of the field, the pc itself isn’t that helpful: with no inside storage, or any utility software program by any means, it might probably actually solely function a bare-bones improvement platform. However since its {hardware} is sort of much like that of different up to date house computer systems, emulating a kind of shouldn’t be too tough, which is precisely what [Ted Fried] did: he managed to show his NABU right into a TRS-80 clone through 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, but it surely additionally holds the TRS-80 ROM and performs real-time translation between peripherals. On 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. On the output aspect, it transfers the TRS-80’s video knowledge to the NABU’s TMS9918 video chip.

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The motherboard of a NABU PC with a Teensy-based CPU upgradeOne drawback [Ted] bumped into was a distinction in display decision: the NABU has a 40×24 character show, whereas the TRS-80 generates a 64×16 character picture. [Ted] solved the vertical distinction by merely preserving the NABU brand on the display always, and determined to only ignore the 24 characters that drop off the fitting aspect – it’s not an enormous situation for a typical BASIC program anyway.

The repurposed NABU may not be an ideal TRS-80 clone, however that’s not the purpose: it exhibits how simply the NABU’s {hardware} might be reprogrammed to do different issues. For instance, [Ted] has already began work on a brand new venture that doesn’t emulate the Z80, however as an alternative runs code immediately on the Teensy’s ARM A9 processor. As you may think, this provides the NABU a number of orders of magnitude extra processing energy, though the sensible use of that is restricted as a result of the CPU nonetheless has to attend for the NABU’s gradual knowledge bus and show chip. [Ted] explains the setup and runs just a few spectacular demos within the video embedded under.

[Ted]’s NABU experiments are an ideal instance of the Teensy board’s flexibility: we’ve already seen the way it can emulate a Z80 in addition to an 8088. We’re additionally curious to see what others will develop with the NABU’s {hardware} – if they’ll nonetheless purchase it, after all.