boards: pjrc: Added Support for the Teensy CLI Tools soft reboot functionality #88024

jbehrensnx · 2025-04-02T07:52:44Z

This PR adds the support for the teensy cli tools soft reboot function by adding a bootloader functionality similar to the bossa one to the teensy boards and adding the ability to pass cli tool flags to the teensy runner.

This allows for flashing the board without triggering the programming pin or pressing the reset button.

nordicjm · 2025-04-02T08:27:11Z

boards/pjrc/teensy4/Kconfig.defconfig

@@ -13,6 +13,33 @@ config BUILD_OUTPUT_HEX
 config DISK_DRIVER_SDMMC
 	default y if DISK_DRIVERS

+config BOOTLOADER_TEENSY


not a defconfig option, move to Kconfig

nordicjm · 2025-04-02T08:27:33Z

boards/pjrc/teensy4/Kconfig.defconfig

+	select SERIAL
+	select USB_DEVICE_STACK
+	select USB_CDC_ACM
+	select CDC_ACM_DTE_RATE_CALLBACK_SUPPORT
+	select USB_DEVICE_INITIALIZE_AT_BOOT


@jfischer-no for review

nordicjm · 2025-04-02T08:27:46Z

boards/pjrc/teensy4/Kconfig.defconfig

+config BOOTLOADER_TEENSY_DEVICE_NAME
+	string "Teensy CDC ACM device name"
+	depends on BOOTLOADER_TEENSY
+	default "USB CDC-ACM"
+	help
+	  Sets the CDC ACM port to watch for reboot commands.


would also move

nordicjm · 2025-04-02T08:27:57Z

boards/pjrc/teensy4/bootloader_teensy.c

+
+static void teensy_reset(const struct device *dev, uint32_t rate)
+{
+	if (rate != 134) {


what is 134?

It is the baudrate the teensy cli tool sets when requesting a soft reboot

use defines/consts for these with descriptive names

nordicjm · 2025-04-02T08:28:08Z

boards/pjrc/teensy4/bootloader_teensy.c

+	/* The programmer set the baud rate to 134 baud.  Reset into the
+	 * bootloader.
+	 */
+	__ASM volatile("bkpt #251");


bkpt #251 is the assembly command to enter the bootloader.

nordicjm · 2025-04-02T08:28:16Z

boards/pjrc/teensy4/bootloader_teensy.c

+	return cdc_acm_dte_rate_callback_set(dev, teensy_reset);
+}
+
+SYS_INIT(teensy_init, APPLICATION, 0);


use board hook

jbehrensnx · 2025-04-02T11:35:15Z

The cdc-acm-uart device needed for this reset functionality is not by default included in the devicetree. My question is, would it make sense to add it in a disabled state? Users would have the choice to enable it or use a different usb device.

jfischer-no · 2025-04-04T07:28:25Z

boards/pjrc/teensy4/Kconfig.defconfig

+if BOOTLOADER_TEENSY
+
+config USB_DEVICE_VID
+	default 0x16c0
+
+config USB_DEVICE_PID
+	default 0x0483
+
+endif # BOOTLOADER_TEENSY


No idea why and whose VID this is, but it should not be here.

jfischer-no · 2025-04-04T08:12:11Z

boards/pjrc/teensy4/Kconfig.defconfig

+	bool "Teensy bootloader support"
+	select SERIAL
+	select USB_DEVICE_STACK
+	select USB_CDC_ACM
+	select CDC_ACM_DTE_RATE_CALLBACK_SUPPORT
+	select USB_DEVICE_INITIALIZE_AT_BOOT


I do not think a board can have its own USB application at board level. Also IMO what the Bossa support at SAM0 SoC level is just wrong. There should be some common place for the bootloader utilities, if at all.

https://docs.zephyrproject.org/latest/hardware/porting/board_porting.html#general-recommendations

pdgendt · 2025-04-29T09:29:19Z

@jbehrensnx PTAL the comments and CI issues

jbehrensnx · 2025-04-30T14:22:57Z

I already implemented some of the feedback (through not pushed yet), but I am not sure when I will have time to work on this in the next couple of weeks.

jbehrensnx · 2025-05-12T13:26:21Z

Moved the bootloader to the soc section to better accommodate other boards, hopefully implemented all feedback and created a snippet for the bootloader, offloading some of the Kconfig configuration.

decsny · 2025-06-16T17:45:57Z

soc/nxp/imxrt/imxrt10xx/bootloader_teensy.c

remove from IMXRT SOC folder, this is board specific and will not be maintained by NXP maintainers

I can do that, but the intention of moving from boards to the soc folder was to facilitate support of boards that are either teensy clones or based on the teensy boards and thus are using the same bootloader, despite not being in the pjrc/teensy4 folder.

No idea how that warrants putting it in the SOC folder because it has nothing to do with the SOC

Put it in a common board folder

Added support for the teensy bootloader, allowing teensy_loader_cli to flash the the teensy40 and teensy41 boards without triggering the reset pin. Signed-off-by: Jan Behrens <[email protected]>

Added ability to set teensy_loader_cli flags from teenys runner. Signed-off-by: Jan Behrens <[email protected]>

Added a snippet that includes all Kconfig options and a dt overlay to allow for easy use of the teensy bootloader. Signed-off-by: Jan Behrens <[email protected]>

sonarqubecloud · 2025-06-20T09:18:13Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

jfischer-no · 2025-06-20T22:37:24Z

snippets/pjrc-teensy-bootloader/pjrc-teensy-bootloader.conf

+CONFIG_USB_DEVICE_STACK=y
+CONFIG_USB_CDC_ACM=y
+CONFIG_CDC_ACM_DTE_RATE_CALLBACK_SUPPORT=y
+CONFIG_USB_DEVICE_INITIALIZE_AT_BOOT=y


This is about to become deprecated.

What would be the new way to do this?

jfischer-no · 2025-06-20T22:44:16Z

snippets/pjrc-teensy-bootloader/pjrc-teensy-bootloader.conf

+CONFIG_USB_DEVICE_VID=0x16c0
+CONFIG_USB_DEVICE_PID=0x0483


We cannot use someone else's vendor ID in the tree.

The thing is, it needs to be there, as the teensy cli looks for this specific VID/PID combination to send the soft-reboot command to.
I honestly have no idea what the process would be for getting permission to use the vendor id for this use case.

There are a handfull of uses of specific vendor ids in the tree, but I dont know their background.

Some other potential solutions, if we can not get permission to use the vendor id, would be to note the correct vendor id in the snippet readme, or look if we can get support for the zephyr vendor id in the teensy cli.

The thing is, it needs to be there, as the teensy cli looks for this specific VID/PID combination to send the soft-reboot command to.

No, it does not need to be there. It is entirely the "teensy cli" problem.

I honestly have no idea what the process would be for getting permission to use the vendor id for this use case.

"Each Vendor ID Number is assigned to one company for its sole and exclusive use, along with associated Product ID Numbers. They may not be sold, transferred, or used by others, directly or indirectly, except in special circumstances and then only upon prior written approval by USB-IF. Unauthorized use of assigned or unassigned USB Vendor ID Numbers and associated Product ID Numbers are strictly prohibited." [0]

Also, I am not going to write about Vendor ID 0x16c0, but you can find some information about it on your own.

There are a handfull of uses of specific vendor ids in the tree, but I dont know their background.

I see only one left. I will remove it as well.

look if we can get support for the zephyr vendor id in the teensy cli.

It would not help you with your custom firmware/product because of [0]. I guess "teensy cli" could be improved to accept VID/PID arguments, but that is not an issue for the Zephyr Project.

[0] https://www.usb.org/sites/default/files/usb-if_member_agreement_080618_1.pdf

Thanks for the clarification.

I did some investigation into teensy_cli, but the required changes are more difficult than they first appeared, so I currently don't plan on pursuing that avenue any further.

At this point it looks to me like the best option is to remove the vendor id from the snippet conf file and mention the correct vendor id in the readme instead.

I am also thinking about adding information about the snippet/soft reboot to the flashing section of the board readme.

addressed. consider creating a boards/pjrc/common/ folder as some other vendors have done.

github-actions bot added the area: West West utility label Apr 2, 2025

github-actions bot requested review from carlescufi, pdgendt and swinslow April 2, 2025 07:53

github-actions bot assigned pdgendt Apr 2, 2025

nordicjm requested changes Apr 2, 2025

View reviewed changes

jfischer-no requested changes Apr 4, 2025

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jbehrensnx force-pushed the teensy-test branch from ffcae83 to 85f6573 Compare May 12, 2025 13:23

github-actions bot added area: Kconfig area: Build System platform: NXP NXP labels May 12, 2025

github-actions bot requested review from 57300, decsny, DerekSnell, dleach02, EmilioCBen, jeremybettis, mmahadevan108, nashif and tejlmand May 12, 2025 13:24

jbehrensnx force-pushed the teensy-test branch from 85f6573 to e6aa34f Compare June 12, 2025 13:01

jbehrensnx requested review from nordicjm and jfischer-no June 12, 2025 14:31

decsny previously requested changes Jun 16, 2025

View reviewed changes

jbehrensnx added 2 commits June 20, 2025 10:52

boards: pjrc: Added Teensy Bootloader Support

cb53014

Added support for the teensy bootloader, allowing teensy_loader_cli to flash the the teensy40 and teensy41 boards without triggering the reset pin. Signed-off-by: Jan Behrens <[email protected]>

west: runners: teensy: Add flags support

be37a03

Added ability to set teensy_loader_cli flags from teenys runner. Signed-off-by: Jan Behrens <[email protected]>

snippets: Added teensy bootloader snippet

33cc4d7

Added a snippet that includes all Kconfig options and a dt overlay to allow for easy use of the teensy bootloader. Signed-off-by: Jan Behrens <[email protected]>

jbehrensnx force-pushed the teensy-test branch from e6aa34f to 33cc4d7 Compare June 20, 2025 08:52

jfischer-no requested changes Jun 20, 2025

View reviewed changes

		CONFIG_USB_DEVICE_VID=0x16c0
		CONFIG_USB_DEVICE_PID=0x0483

boards: pjrc: Added Support for the Teensy CLI Tools soft reboot functionality #88024

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boards: pjrc: Added Support for the Teensy CLI Tools soft reboot functionality #88024

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jbehrensnx commented Apr 2, 2025

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sonarqubecloud bot commented Jun 20, 2025

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