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Type: Posts; User: john_c_kennedy

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    I finally got this to link, I changed the startup...

    I finally got this to link, I changed the startup file extension to .c rather than .cpp, linked the .ARM.extab and .ARM.exidx sections to ITCM with most of the other code and it linked without...
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    Thanks Pieter, I'm using C++ and I've tried...

    Thanks Pieter, I'm using C++ and I've tried -fno-exceptions but it doesn't help. But as I mentioned I'm using NXP's MCUXpresso not Teensyduino. And MCUXpresso has a managed linker script mechanism...
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    Thanks Paul, so you put the .ARM.exidx section in...

    Thanks Paul, so you put the .ARM.exidx section in ITCM also. My version of the Teensy4.1 linker script doesn't have that so it must be old?
    Thanks again,
    John
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    .ARM.exidx section question

    I'm using MCUXpresso for Teensy 4.1 so you guys might not be able to help with this question. But I'm modifying the linker script to link part of the code to run in ITCM RAM and I get an error with...
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    You can use MCUXpresso to develop code for Teensy...

    You can use MCUXpresso to develop code for Teensy 4.x, you just have to create a hex file from the .axf file. Just right click on the .axf file and select Binary Utilities and then Create hex. The...
  6. Me too but for Kicad. Schematic symbols and PCB...

    Me too but for Kicad. Schematic symbols and PCB footprints for T4.x would be very helpful.
    John
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    Alvaro, as I recall the FreeRtos lpuart demo for...

    Alvaro, as I recall the FreeRtos lpuart demo for MCUXpresso uses LPUART1 for the serial port, which is connected to pins 24,25 on the Teensy 4.1. So it doesn't use the USB serial port. You need a...
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    You have to create a hex file with MCUXpresso...

    You have to create a hex file with MCUXpresso then just use the Teensy loader to flash it to Teensy4.1. MCUXpresso creates a header in the hex file that is compatible with the Teensy loader as long...
  9. Yes, very interesting, I'll have to try it. Only...

    Yes, very interesting, I'll have to try it. Only I don't like Teensyduino, so I'll have to see if I can get it working with the MCUXpresso IDE.
  10. Well, I'm not exactly a novice, I've been doing...

    Well, I'm not exactly a novice, I've been doing embedded software/hardware for over 40 years, mostly for medical devices, and most recently using Xilinx Zynq parts. I'm retired now, but I love...
  11. Michael, again very helpful thank you. John

    Michael, again very helpful thank you.
    John
  12. Thanks Michael, I think I understand now, in the...

    Thanks Michael, I think I understand now, in the .text.itcm section it includes everything with the .fastrun attribute and everything with the .text* attributes. So I assume the compiler assigns a...
  13. No you didn't answer my question. If I write...

    No you didn't answer my question. If I write some code in a .c file and do not use either FASTRUN or FLASHMEM how does the linker know what segment to put it in since I didn't specify anything...
  14. Thanks Paul for clearing this up, very helpful. ...

    Thanks Paul for clearing this up, very helpful. I'm not currently trying to do anything special with memory, just trying to understand how all this works. It looks to me like the linker script puts...
  15. Yep, you are correct she was using the NXP...

    Yep, you are correct she was using the NXP MCUExpresso IDE which by default links everthing to run in flash.
  16. Thanks for the link. But actually according to...

    Thanks for the link. But actually according to the diagram only code labeled FASTRUN __attribute__ ((section(".fastrun") ))
    is copied to ram, every thing labeled FLASHMEM...
  17. I beg to differ, if you look at the hex file the...

    I beg to differ, if you look at the hex file the load address is in Flash. Also if you look at the linker script files imxrt1062.ld and imxrt1062_t41.ld the .text section is linked into Flash, only...
  18. Thanks Michael. My thought was to read the image...

    Thanks Michael. My thought was to read the image from SD copy it to RAM and run out of RAM. This would save wear and tear on the FLASH and SD cards are pretty cheap, especially when debugging...
  19. Is it possible to boot from SD Card?

    Is it possible to boot from the SD card?
    Has anyone done this?
    Does anyone know how to make this work?
    Thanks,
    John
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    I have FreeRtos running on Teensy4.1, but I used...

    I have FreeRtos running on Teensy4.1, but I used the NXP MCUXpresso IDE. Built the stock lpuart demo with no changes and it just worked!
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    MIMRT1062 Serial Downloader

    I've been reading the RM so I'm just curious, does anyone know:
    Does Teensy4.x respond to the serial download protocol used by the on chip serial downloader described in section 9.9 pg. 268 of the...
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    Wise choice, Teensy4.x and Teensyduino make a...

    Wise choice, Teensy4.x and Teensyduino make a great combination, Teensy 4.x is several orders of magnitude better than the old AVR based Arduino boards so the're a great way to go and not too...
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    SWO debugging is disabled in Teensy 4.x by...

    SWO debugging is disabled in Teensy 4.x by internal fuses in the MCU that can't be reversed. The JTAG pins go to the on board MKLO2 MPU which apparently uses JTAG Boundry Scan to implement the...
  24. After further thinking my preference would be to...

    After further thinking my preference would be to leave the MKLo2 in place to manipulate the PSWITCH properly for a power on reset and the config signals for bootup, but to modify/replace the code so...
  25. 2 MKLO2 pins un-accounted for?

    Paul,
    I am also very interested in connecting a JTAG debugger to the T4.1 (just purchased 2 of them) and this info is very helpful. But looking at the schematics there are still 2 pins connected to...
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