The NABU Laptop induced a bit of a buzz in the retrocomputing group a when back. Following all, it doesn’t come about often that a big batch of brand name-new computer systems from the 1980s quickly results in being available on eBay. Out of the box, the laptop or computer itself isn’t that helpful: with no interior storage, or any software software in any way, it can definitely only serve as a bare-bones improvement system. But since its hardware is really very similar to that of other present-day household pcs, emulating 1 of individuals shouldn’t be much too tough, which is specifically what [Ted Fried] did: he managed to turn his NABU into a TRS-80 clone by using his MCLZ8 CPU emulator.
The MCLZ8 is mainly an 800 MHz Teensy CPU with an adapter board that will allow it to be plugged into a Z80 socket. It emulates the Z80 CPU in real-time, but it also retains the TRS-80 ROM and performs authentic-time translation among peripherals. On the enter side, it reads out the ASCII figures coming in from the NABU’s 8251A UART and retailers them in the virtual TRS-80’s keyboard buffer. On the output aspect, it transfers the TRS-80’s video clip details to the NABU’s TMS9918 video chip.
Click through the break for far more!
One particular dilemma [Ted] ran into was a variation in monitor resolution: the NABU has a 40×24 character display, when the TRS-80 generates a 64×16 character picture. [Ted] solved the vertical variance by just preserving the NABU logo on the display screen at all moments, and made the decision to just overlook the 24 characters that drop off the suitable side – it’s not a large issue for a common Fundamental software in any case.
The repurposed NABU might not be a ideal TRS-80 clone, but that’s not the issue: it exhibits how simply the NABU’s components can be reprogrammed to do other items. For instance, [Ted] has already began perform on a new project that does not emulate the Z80, but as a substitute runs code immediately on the Teensy’s ARM A9 processor. As you might think about, this presents the NABU numerous orders of magnitude much more processing energy, although the practical use of this is minimal for the reason that the CPU however has to wait around for the NABU’s gradual information bus and screen chip. [Ted] points out the setup and operates a number of impressive demos in the movie embedded under.
[Ted]’s NABU experiments are a good case in point of the Teensy board’s adaptability: we have already noticed how it can emulate a Z80 as very well as an 8088. We’re also curious to see what others will produce with the NABU’s components – if they can nonetheless get it, of class.