NP-41 Emulator (may be)
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10-15-2015, 06:45 AM
Post: #89
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RE: NP-41 Emulator (may be)
(10-12-2015 10:33 PM)Harald Wrote: Chris is aiming at something completely different here. I think somewhere he said it is supposed to be a "retro toy". But it will be a very useful toy as well. And I am sure I will want one too I fully agree with you. I only brought up what Richard Ottosen and I built as an example of something that can be done, albeit at greater expense. I actually considered trying to develop a calculator variant with a segmented LCD, but retaining the four-level stack display. The problem is that it needs 831 display segments, more than any of the common microcontrollers with LCD drive can handle, or even any common standalone LCD driver chips. At one time I thought doing that would almost force going to a custom chip-on-glass display module, which is unfortunately much more expensive to have made than the purely segmented LCD of the single-line NP-41. However, when I researched it more, I found that Chinese masked-ROM microcontrollers such as the GeneralPlus GPL191C offer sufficiently high segment counts. They don't have enough RAM for a sophisticated calculator, but could be used as a smart LCD controller. Compared to US and European IC vendors, the Chinese vendors have low mask NRE charges and low minimum volumes, so that's not completely unreasonable for a "high-end" hobby project. Another way to get the four-line stack display would be to actually use four LCDs, with four LCD-driving microcontrollers, where three are just used as slave display drivers. When I hacked the 41 to do the multiline display, I only implemented that for the stack, because that was fairly easy. It would also be possible to display all 24 characters of the ALPHA register on two lines, rather than scrolling, and to display multiple program lines in PRGM mode, but that would take a lot more hacking. It's been somewhat easier adding these features to the Free42 code base. |
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