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  • mborgerson's Avatar
    Yesterday, 04:54 PM
    Have you considered adapting your project to use the T4.0? Unless you require the touch input or something specific to the T3.2 ADC, you should be able to plug a T4.0 into the T3.2 socket and recompile your software. ...
    2 replies | 171 view(s)
  • mborgerson's Avatar
    Yesterday, 04:34 PM
    Yeah, I got so tired of making that mistake that I wrote a macro to remind myself that I'm setting a corner: #define SetCorner(reg, h, v) reg = (h<<16 + v) The macro is used like this: ...
    51 replies | 8901 view(s)
  • mborgerson's Avatar
    02-04-2023, 05:04 PM
    I found your code in pop_lcd_diff_buff.ino a bit confusing. It seems that you call PXP_Init every time through the loop. I'm not sure it is a good idea to reset the PXP and set the buffers each time through the loop....
    51 replies | 8901 view(s)
  • mborgerson's Avatar
    02-03-2023, 08:15 PM
    Did you remove the lines in PXP_Start from PXP_Init? I tried the same thing, but renamed the new function PXP_XStart(), since I already had PXPStart. Every thing seemed to work as expected. Even if I removed the...
    51 replies | 8901 view(s)
  • mborgerson's Avatar
    01-31-2023, 04:54 PM
    I think you're on track. I did a lot of experimenting with buffer offsets and PS buffer definitions when I did my slide show application. I was doing image scaling for zoom effects, offsets to move the slide...
    51 replies | 8901 view(s)
  • mborgerson's Avatar
    01-29-2023, 05:59 AM
    AHA! If you trash the cache on every reference to EXTMEM, you lose the performance benefit you would get for every transfer from within the cache. This shows why cache management requires careful analysis. ...
    5 replies | 202 view(s)
  • mborgerson's Avatar
    01-29-2023, 02:27 AM
    I get this, and I understand that you might not want to add tests for memory source and destination regions to all memcpy() calls, as the function has been written in assembly for maximum performance. However, there...
    5 replies | 202 view(s)
  • mborgerson's Avatar
    01-28-2023, 09:38 PM
    I've been working with the PXP and CSI to collect and process camera images. Recently, I was writing a test pattern into a DMAMEM or EXTMEM buffer, then processing it with the PXP. It seems necessary to use an...
    5 replies | 202 view(s)
  • mborgerson's Avatar
    01-28-2023, 09:02 PM
    This issue was due to the fact that I was not calling arm_dcache_flush_delete((void *)PXP_PS_BUF, bsize); BEFORE the rotation. I was writing the pixel pattern into the source image in a foreground function, and some...
    51 replies | 8901 view(s)
  • mborgerson's Avatar
    01-27-2023, 11:18 PM
    I assume that you are using an NPN transistor, and when the input goes high, the transistor turns on and pulls down the Teensy input pin. This is a circuit that calls for some filtering capacitors either at the Teensy...
    7 replies | 155 view(s)
  • mborgerson's Avatar
    01-27-2023, 10:56 PM
    I've figured out the problem I was having with the rotations. I was not properly setting the PXP_OUT_PITCH register before doing the rotation. That register sets the number of bytes between two vertically adjacent...
    51 replies | 8901 view(s)
  • mborgerson's Avatar
    01-26-2023, 09:34 PM
    I cleaned up my test code and ran some tests: DTCM(RAM1) to DTCM, DMAMEM or EXTMEM rotates properly for square buffers. DTCM source is showing issues with rectangular buffers for all destinations. I suspect this...
    51 replies | 8901 view(s)
  • mborgerson's Avatar
    01-26-2023, 05:56 PM
    There's a note in the illustration on page 1923 of the reference manual in the section about PXP rotation: I believe that the PXP fetches and stores using direct memory access and will not benefit from caches for...
    51 replies | 8901 view(s)
  • mborgerson's Avatar
    01-25-2023, 06:04 PM
    Got around to wiring up my ILI9486 breakout display to my custom board Teensy MM with PSRAM :cool: Tested the sketch, but I am running into some issues: 1. The image is being rotated by 90 degrees but it looks...
    51 replies | 8901 view(s)
  • mborgerson's Avatar
    01-23-2023, 05:43 PM
    I used the PXP end-of-conversion interrupt to put together an All-Background camera viewfinder using the asynchronous update capability of the ILI9341_T3N libarary. The process looked like this: 1. Setup the...
    51 replies | 8901 view(s)
  • mborgerson's Avatar
    01-20-2023, 01:03 AM
    I wouldn't rely too heavily on the example code on post #13. The dca function is taking an input parameter of a bearing in degrees and using the sin() function without converting the angle to radians!
    20 replies | 1039 view(s)
  • mborgerson's Avatar
    01-14-2023, 08:30 PM
    It just occurred to me that it may not be a good idea to directly connect the serial output of a T4.1 to an input on another T4.1 that may be powered off. Isn't that going to drain a lot of current from the serial...
    16 replies | 469 view(s)
  • mborgerson's Avatar
    01-14-2023, 08:18 PM
    This application cries out for prefix bytes to help synchronization and a checksum to verify the data integrity--especially if the data will be controlling anything that can smoke, burn, or explode! Here is a sample...
    16 replies | 469 view(s)
  • mborgerson's Avatar
    01-12-2023, 06:52 PM
    If the data starts scrambling after a few minutes, it may be an indication that your receiving system is not reading data as fast as the other system is sending. It wasn't clear from your original post exactly how...
    16 replies | 469 view(s)
  • mborgerson's Avatar
    01-11-2023, 08:00 PM
    You library looks like what I need. It handles a greater variety of packet types and output data than does my minimalist code. I have extended my example code to handle the collection and logging of the data, as...
    4 replies | 156 view(s)
  • mborgerson's Avatar
    01-11-2023, 07:41 PM
    I think that specification is probably for a system using real-time correction input from a base station. Then there's the issue of accuracy vs. precision. When I plot the position of my jeep parked in my driveway,...
    4 replies | 156 view(s)
  • mborgerson's Avatar
    01-11-2023, 02:36 AM
    A few weeks before Christmas, a friend contacted me about putting together a program to log position and IMU data from a ZED-F9R to help a friend of his analyze his performance as an amateur driver of a Porsche 911 on...
    4 replies | 156 view(s)
  • mborgerson's Avatar
    01-11-2023, 12:20 AM
    Look for the addMemoryForRead() function which is part of the hardware serial driver: // before setup() uint8_t bigserialbuffer; //in setup(): Serial1.begin(230400); ...
    16 replies | 469 view(s)
  • mborgerson's Avatar
    01-05-2023, 04:35 PM
    I would start by removing the pinMode and digitalWrite lines. Those are setting up pin 13, however, the tft.begin() is coming along a few microseconds later and switching pin 13 to be the SPI clock signal. Perhaps...
    384 replies | 110763 view(s)
  • mborgerson's Avatar
    12-30-2022, 04:18 PM
    I have not yet posted the code to GitHub for two reasons: 1. I want to make sure that what I post is compatible with the licensing and intentions of the original author, Stephen Brumme. 2. I have encountered...
    10 replies | 1580 view(s)
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About mborgerson

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About mborgerson
Biography:
building embedded systems for oceanographers since 1978
Location:
Corvallis, OR
Interests:
travel
Occupation:
Retired embedded systems engineer

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In search of Teensy 3.2, Can anyone help? Yesterday 04:54 PM
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