MK20DX128VFM5 chip usage consultation

[zhaofan123]

I am a newbie and have a lot of doubts, and I would very much like to get the help of your seniors.

I am using the MK20DX128VFM5 chip, and when I connect the computer directly through USB, the computer does not recognize any device, and when I press the reset button to enter, there is no phenomenon.

So I started measuring the REST-B pin of the chip, and I had applied it high, but the chip would force the signal low. When I change a chip that someone else has used, press and hold the reset button to enter, a high level signal appears on the REST-B pin, and the computer can recognize the device and display 'BOOTLOADER'.But when I drag the firmware, the device still doesn't respond.

What do I need to do to make my computer recognize the correct device and be able to refresh the program? I'm not sure if I overlooked some important steps during the operation.

Anyone who can provide answers or documentation would be appreciated.

[ErichStyger · Accepted solution]

Hi @zhaofan123 ,

your device does not have a USB bootloader on it in the ROM. You need to program it first with an application running the USB stack.

I hope this helps,

Erich

[zhaofan123]

There is one more thing I would like to confirm with you. Is the USB bootloader for MK20DX128VFM5 chip the default? Or do I need to create different USB bootloaders based on different functional requirements?

[ErichStyger]

The K20 has no ROM bootloader. You need to implement one for your needs.

[zhaofan123]

Do you have any K20 programs available for KDS here? I would like to make some references and modifications.

[ErichStyger]

sure!

here you go:

https://github.com/ErichStyger/mcuoneclipse/tree/master/Examples/KDS/tinyK20

https://github.com/ErichStyger/mcuoneclipse/tree/master/Examples/KDS/FRDM-K20D50M

The tinyK20 board is basically a stripped down circuit from the FRDM boards, see

https://mcuoneclipse.com/2015/05/17/tinyk20-open-source-arm-debuguniversal-board-first-prototypes/

[zhaofan123]

I found these links in the process of learning:
https://community.nxp.com/t5/University-Programs-Knowledge/uTasker-Bootloader-Porting-Guide/ta-p/111...
https://www.utasker.com/kinetis/FRDM-K20D50M.html
Does this help me to burn the ROM bootloader?

[zhaofan123]

I have one more question I would like to get your confirmation. When I load the bootloader for the K20, can I load it directly with USB? Or do I need to use the SWD interface to burn the program?

[ErichStyger]

You need initially a debug probe with SWD.

See for example https://mcuoneclipse.com/2018/03/03/flash-resident-usb-hid-bootloader-with-the-nxp-kinetis-k22-micro...

[zhaofan123]

Where can I buy a debug probe with SWD? Can I trouble you to provide a link to this?

[ErichStyger]

For example the MCU-Link:

https://mcuoneclipse.com/2020/11/29/new-mcu-link-debug-probe-from-nxp/

Or the Pro version:

https://mcuoneclipse.com/2021/10/17/new-mcu-link-pro-debug-probe-with-energy-measurement/

You find them on Mouser/etc or directly from NXP.com

[zhaofan123]

Hello, I now get the USB bootloader for MK20 chip, but it is a hexadecimal file type. I have purchased MCU-Link, what software should I download to program the chip? Looking forward to hearing from you.

[ErichStyger]

You can use the MCUXpresso IDE, see https://mcuoneclipse.com/2017/05/06/using-eclipse-to-program-binary-files-to-an-embedded-target/

Or you can use the LinkServer command line utility, see https://mcuoneclipse.com/2023/05/14/linkserver-for-microcontrollers/

[zhaofan123]

I read your blog, then added K20 and was able to query it successfully.

But as I read this,

I have some doubts:

I don't know what 'implicit wildcards' is.My device is MK20DX128VFM5 and my board is Analog Devices' EVAL-ADICUP3029, so how exactly should I enter instructions when entering?

[ErichStyger]

What matters in this case is the device, not the board.

The board would be only relevant if you have external RAM or FLASH, as that would be board specific.

Implicit wildcards means that you did not specify the full device/board tuple.

[zhaofan123]

When I input commands, just use a * sign to replace the board behind the device, right?

[ErichStyger]

You don't need a * as a wildcard, it does that implicitly

[zhaofan123]

I just installed the LinkServer command line utility and tried to follow your blog to use it. But when I enter the command shown in the figure below, the computer shows the supported devices as I thought, and I can't query any information about the K20.

[ErichStyger]

As a consideration, have you thought about adding the K20 to the list of devices for LinkServer?

[zhaofan123]

I hope to add K20, but I don't know how to do so. It would be great if I could get your help.Also, I would like to confirm one thing, is it not possible to burn. HEX files using KDS?

[ErichStyger]

See https://mcuoneclipse.com/2023/07/30/using-legacy-devices-with-linkserver/

And what file types you can load depends not on the IDE, but on the debug probe. See https://mcuoneclipse.com/2017/05/06/using-eclipse-to-program-binary-files-to-an-embedded-target/