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Type: Posts; User: Mike Chambers

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  1. I got the DMA code working well. The difference...

    I got the DMA code working well. The difference is noticeable. Especially during VGA palette fades. Very smooth! Thanks for the tip. I ended up settling on 25 FPS, otherwise the frequent 64 KB memory...
  2. Thanks! I was not even aware that there was a DMA...

    Thanks! I was not even aware that there was a DMA mode. I was using tft.DrawPixel. I knew there had to be a better way. 50 FPS sounds great to me! It takes about 200-300 ms (!!) to fill a 320x240...
  3. Yes, it's actually a port of a Windows/Linux...

    Yes, it's actually a port of a Windows/Linux version I started writing from scratch back in 2011 called Fake86. I was very new to the C language then, and it shows. The code is very ugly! It is at...
  4. Jean-Marc, VERY nice project! I'll have to give...

    Jean-Marc, VERY nice project! I'll have to give yours a try and check out the various systems.

    It looks like you're actually using my own 8086 code in yours! :)

    It didn't run so well on the...
  5. A Teensy 4.0 demo. Playing the old Stunt Island DOS game. Real time 3D.

    The Teensy 4.0 is a powerhouse, I'm impressed! Playing an old DOS game, emulated 8086 code on the T4.0 with real time 3D rendered gameplay. It handles it with no problem. I suspect it would be a lot...
  6. I'm just going to hook this up to some regular...

    I'm just going to hook this up to some regular GPIO pins and do some bit-banging, I don't need huge amounts of bandwidth and I'm just trying to access the blocks raw. No file system needed.

    If...
  7. Sorry for the delay! I was at work all day. ...

    Sorry for the delay! I was at work all day.

    Messy-looking wiring, you say? Now that I can do! Here it is. :eek:

    https://i.imgur.com/szBhTg9.jpg

    Ground is taking a bit of a long path to the...
  8. Thanks for the link. I will incorporate these...

    Thanks for the link. I will incorporate these tips, however it causes the LCD to stop working even without connecting MOSI/MISO/CS to the SD board. All I have to do is connect SCLK alone, leave the...
  9. LCD screen stops functioning when also hooking up SCLK to Teensy SD adapter

    Getting the final feature of my project working on my new T4.0 involves hooking up the Teensy SD adapter to the breadboard. The LCD screen works fine until I connect the SCLK of the SD board. These...
  10. There's certainly no rush needed for making it...

    There's certainly no rush needed for making it faster. This thing is like lightning.




    Now that you say that, I realize I forgot to put a level shifter for the keyboard on my T3.6 version of...
  11. That's true. Unless it wants to allocate some...

    That's true. Unless it wants to allocate some memory there during runtime. Maybe Paul or someone else could chime in on whether we should be leaving a bit of free space in that segment.



    Or DOS...
  12. I basically just copied what KurtE was doing in...

    I basically just copied what KurtE was doing in his post. I put 512 KB in the DMAMEM area, and the other 128 KB in the regular global memory.


    uint8_t RAM0[524288] DMAMEM;
    uint8_t RAM1[131072];...
  13. KurtE, this is exactly what I needed to know,...

    KurtE, this is exactly what I needed to know, thanks! The DMAMEM keyword allowed me to split this up into two arrays, and it compiled just fine. :)
  14. Ah yes, the linker error I got was complaining...

    Ah yes, the linker error I got was complaining that it was out of space in the DTCM region. So, I'll just need to figure out how to put some of it in the other 512 KB.
  15. I considered that too after making this post, and...

    I considered that too after making this post, and tried even breaking it into ten 64 KB arrays and that wouldn't link, either. So you're probably right about there being some other syntax to use the...
  16. I can't seem to use all of the Teensy 4.0's memory?

    I'm working on a project that requires a very large amount of RAM. I've tried allocating 640 KB in two different ways.

    I first tried to just declare a global array like so:


    uint8_t...
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    I just ordered my 4.0! I'm very excited. You...

    I just ordered my 4.0! I'm very excited. You can't beat this for price and performance. Your move, Arduino.

    I built an 80186 PC emulator with the 3.6, and what was holding back the performance was...
  18. Am I correct in assuming that the FIFO can only...

    Am I correct in assuming that the FIFO can only be used on SPI0? I'll need to rewire the board slightly if that's the case. The RAM is on SPI1 right now, I'll need to share the LCD's bus with it.
  19. That 8 MB RAM chip looks great! I'll need to see...

    That 8 MB RAM chip looks great! I'll need to see if I can get one of those.

    I also didn't know about the FIFO capability, I'm going to have to see what kind of improvements can be had with that....
  20. Thanks for the info, I wasn't aware of those...

    Thanks for the info, I wasn't aware of those options. I'll give them a try tonight and see how it goes. The emulator actually runs a bit faster than it shows in these videos, as tonight I realized I...
  21. Teensy 3.6 based 8086 PC emulator with CGA graphics, PS2 keyboard

    Hi all! This is something I did last year, but thought I'd finally share. I wrote a PC-based PC emulator some years ago, and later wanted to see how it worked on a microcontroller. So, I ripped the...
  22. Hi Paul! Yes, that's the one, from here:...

    Hi Paul! Yes, that's the one, from here: https://github.com/njh/EtherCard

    I've been just using packet forwarding from Windows through the USB serial interface, which has been working well. I...
  23. Yes, I know how switches work....

    Yes, I know how switches work. Broadcast/multicast and packets directed at its own MAC are what it needs. The Teensy will be running (via emulation) MS-DOS and a DOS-based packet driver, so it just...
  24. I'm still having no luck with this, I need to...

    I'm still having no luck with this, I need to investigate some more. Thanks for the link about the W5100 and raw Ethernet frames! Unfortunately, it still is not suitable because it cannot be placed...
  25. Since 240 / 96 = 2.5, I'll just try throwing 3 or...

    Since 240 / 96 = 2.5, I'll just try throwing 3 or 4 NOPs in there and seeing what it does first.

    I noticed that about the AVR SPI reigsters as well. One of my troubleshooting steps was replacing...
  26. Thanks, yeah that makes sense. I'm actually...

    Thanks, yeah that makes sense. I'm actually running at 240 mhz. (Necessary for this project)

    I did try it at 96 MHz, but did not remove SPI.begin(). I know the enc28j60 library also initializes...
  27. Hmm, so I tried the UIPEthernet library. Compiled...

    Hmm, so I tried the UIPEthernet library. Compiled one of the examples. That doesn't work, either.

    Just to make sure my board hasn't gone bad since it was tested on my Arduino, I hooked it back up...
  28. Sorry about not including code. I've just made a...

    Sorry about not including code. I've just made a simple sketch to demonstrate the problem.

    The firmware value returned is 7 for me. I don't think the wiznet adapter is an option for me, because...
  29. ENC28J60 initializing and reading firmware version, but not receiving packets on T3.6

    I've got an ENC28J60 hooked up to my Teensy 3.6. It initializes properly, but even after setting promiscuous mode, it never receives any packets. I'm using the low-level raw packet functions from the...
  30. Impressive work! This really shows off what the...

    Impressive work! This really shows off what the Teensy is capable of.

    I also noticed when I look at the code, that your CPU core is based on the 6502 emu I wrote some years back. Nice to see it...
  31. Thank you! So, unless I'm reading wrong, none of...

    Thank you! So, unless I'm reading wrong, none of the GPIO ports have all of their pins broken out on the board?
  32. Pin to port mapping reference for Teensy 3.6?

    Hi, I'm looking for a pin to port mapping reference for the Teensy 3.6. Like, say I use this code:

    PORTA = 0x80;

    Which pins on the Teensy correlate to which bits on what the CPU considers to be...
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