5 ms·

Really, using a Teensy 4.0 to make scrolling faster? That seems really overkill to me. You could make a small computer out of a Teensy 4, quite excessive to use

by mogery 4y ago

Really, using a Teensy 4.0 to make scrolling faster? That seems really overkill to me. You could make a small computer out of a Teensy 4, quite excessive to use it as a display-out.

HeyLaughingBoy 4y ago
[shrug] I will happily use an entire arduino clone to produce a periodic pulse when it could be done with an NE555 timer. One will take me approximately 2 minutes, the other more than 2 hours. When your build quantity == one, the concept of overkill becomes less meaningful.
- kragen 4y ago
  I recall some Keysight "educational" video where the guy says, "This is my million-dollar cellphone charger" and plugs his cellphone into a USB port on a fancy oscilloscope.
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JKCalhoun 4y ago
That's true. If I had been able to get the hardware scrolling to work on the ILI9341 no doubt it could have easily run on a lower-end Teensy. Maybe someone more clever than me can get it to work. It sucks to resort to brute force.
- hedgehog 4y ago
  I'm a little surprised there's not a better LCD controller for this kind of application, even a little iCE40 should be enough to implement a character display and smooth scrolling on both axes.
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kragen 4y ago
Vast overkill in this respect is historically accurate; the VT100 was built around an 8085, for example.
- bitwize 4y ago
  The 8008 was invented for a terminal application -- the Datapoint 2200. So not only were VDTs effectively microcomputers since the 70s, but Intel's main processor line up until the present day owes its existence to VDT applications.
  - kragen 4y ago
    Yeah, but the Datapoint 2200 was kind of a high-end niche thing, I think. I've never seen one in real life. (And I don't think anyone ever actually built a terminal around an 8008.) The VT100, by contrast, was ubiquitous. It also came out in the 01970s: 01970 for the 2200, 01978 for the VT100. Early-01970s terminals like the ADM3A or the Tek 4014 more typically were not microcomputers at all, just discrete logic. The VT52, with a much richer escape sequence language than the ADM3A, was kind of on the borderline: https://vt100.net/docs/vt52-mm/chapter4.html https://vt100.net/docs/vt52-mm/chapter4.html http://xahlee.info/kbd/iold51593/EK-VT52-MM-002_maint_Jul78_5f208.pdf http://xahlee.info/kbd/iold51593/EK-VT52-MM-002_maint_Jul78_... It had a "microprogram" in ROM with conditional jumps, but lacked capabilities like arithmetic, bitwise operations, and subroutines that could be called from more than one place; many of the instructions are things like "start printer" and "jump if UART has received a character".
    - AndresNavarro 4y ago
      A couple of years ago I did a vt52 emulator with an fpga, no processor at all (not even a soft-processor). Just regular ram and sequential logic. You can use a simple processor for some commands, but scrolling is best handled in hardware i think: https://github.com/AndresNavarro82/vt52-fpga https://github.com/AndresNavarro82/vt52-fpga
      - kragen 4y ago
hypertele-Xii 4y ago
Computers are getting cheaper faster than we can figure out what to do with them. Overkill is fine.

by mogery 4y ago

Really, using a Teensy 4.0 to make scrolling faster? That seems really overkill to me. You could make a small computer out of a Teensy 4, quite excessive to use it as a display-out.

HeyLaughingBoy 4y ago

[shrug] I will happily use an entire arduino clone to produce a periodic pulse when it could be done with an NE555 timer. One will take me approximately 2 minutes, the other more than 2 hours. When your build quantity == one, the concept of overkill becomes less meaningful.

kragen 4y ago
I recall some Keysight "educational" video where the guy says, "This is my million-dollar cellphone charger" and plugs his cellphone into a USB port on a fancy oscilloscope.

deleted 4y ago

[deleted]

JKCalhoun 4y ago

That's true. If I had been able to get the hardware scrolling to work on the ILI9341 no doubt it could have easily run on a lower-end Teensy. Maybe someone more clever than me can get it to work. It sucks to resort to brute force.

hedgehog 4y ago
I'm a little surprised there's not a better LCD controller for this kind of application, even a little iCE40 should be enough to implement a character display and smooth scrolling on both axes.

deleted 4y ago

[deleted]

kragen 4y ago

Vast overkill in this respect is historically accurate; the VT100 was built around an 8085, for example.

bitwize 4y ago
The 8008 was invented for a terminal application -- the Datapoint 2200. So not only were VDTs effectively microcomputers since the 70s, but Intel's main processor line up until the present day owes its existence to VDT applications.
- kragen 4y ago
  Yeah, but the Datapoint 2200 was kind of a high-end niche thing, I think. I've never seen one in real life. (And I don't think anyone ever actually built a terminal around an 8008.) The VT100, by contrast, was ubiquitous. It also came out in the 01970s: 01970 for the 2200, 01978 for the VT100. Early-01970s terminals like the ADM3A or the Tek 4014 more typically were not microcomputers at all, just discrete logic. The VT52, with a much richer escape sequence language than the ADM3A, was kind of on the borderline: https://vt100.net/docs/vt52-mm/chapter4.html https://vt100.net/docs/vt52-mm/chapter4.html http://xahlee.info/kbd/iold51593/EK-VT52-MM-002_maint_Jul78_5f208.pdf http://xahlee.info/kbd/iold51593/EK-VT52-MM-002_maint_Jul78_... It had a "microprogram" in ROM with conditional jumps, but lacked capabilities like arithmetic, bitwise operations, and subroutines that could be called from more than one place; many of the instructions are things like "start printer" and "jump if UART has received a character".
  - AndresNavarro 4y ago
    A couple of years ago I did a vt52 emulator with an fpga, no processor at all (not even a soft-processor). Just regular ram and sequential logic. You can use a simple processor for some commands, but scrolling is best handled in hardware i think: https://github.com/AndresNavarro82/vt52-fpga https://github.com/AndresNavarro82/vt52-fpga
    - kragen 4y ago

hypertele-Xii 4y ago

Computers are getting cheaper faster than we can figure out what to do with them. Overkill is fine.