Can I use USB serial as normal for Teensy 4.0/4.1 without bootloader IC?

[chensx2012]

When I burn firmware to custom Teensy 4 MCU, I used the pre-programmed bootloader IC by Paul. After that, can I run my program as normal (such as USB serial, and everything else) if I remove the bootloader IC? Moreover, if I remove the bootloader IC, is there any way to burn the arduino .hex file?

 

[chensx2012]

When I burn firmware to custom Teensy 4 MCU, I used the pre-programmed bootloader IC by Paul. After that, can I run my program as normal (such as USB serial, and everything else) if I remove the bootloader IC? Moreover, if I remove the bootloader IC, is there any way to burn the arduino .hex file?

Anyone have any ideas or suggestions? Thanks in advance.

 

[defragster]

As read here - No. The bootloader chip actively controls and uses and programs the MCU to load the HEX file. Without the bootloader chip properly connected the MCU will only run the existing program.

Also note indications are the bootloader chip on T_4.x is paired with the MCU AFAIK. So, if multiple custom boards exist the bootloader chip that was used to initialize the MCU is the only one that will recognize and program that MCU.

There is a non-PJRC supported option where code programmed within the target sketch. See this post: Micromod-Teensyduino-firmware-upload-question

 

[chensx2012]

As read here - No. The bootloader chip actively controls and uses and programs the MCU to load the HEX file. Without the bootloader chip properly connected the MCU will only run the existing program.

Also note indications are the bootloader chip on T_4.x is paired with the MCU AFAIK. So, if multiple custom boards exist the bootloader chip that was used to initialize the MCU is the only one that will recognize and program that MCU.

There is a non-PJRC supported option where code programmed within the target sketch. See this post: Micromod-Teensyduino-firmware-upload-question

Thanks for your useful reply. At the beginning, I successfully programed my custom teensy 4.0 with Paul's bootloader IC. After that, if I remove the bootloader IC, can the teensy MCU be recognize as USB Serial and run existing program?

 

[chensx2012]

As read here - No. The bootloader chip actively controls and uses and programs the MCU to load the HEX file. Without the bootloader chip properly connected the MCU will only run the existing program.

Also note indications are the bootloader chip on T_4.x is paired with the MCU AFAIK. So, if multiple custom boards exist the bootloader chip that was used to initialize the MCU is the only one that will recognize and program that MCU.

There is a non-PJRC supported option where code programmed within the target sketch. See this post: Micromod-Teensyduino-firmware-upload-question

I made a custom Teensy 4.0 recently. With Paul's bootloader IC, I can sucesessfully program. But after I disconnected the bootloader IC, the custom teensy just disappeared, neither as Com port or as USB bootloader device. When I connected the USB cable, nothing happened in the device manager of windows 10.

 

[PaulStoffregen]

After that, if I remove the bootloader IC, can the teensy MCU be recognize as USB Serial and run existing program?

If you remove the bootloader chip, and if you've followed the Teensy 4.x design, you'll need to provide some other hardware to accomplish step #7 of the power up sequence. On the T4 bootloader page, scroll down to "Power Up Sequence" for details. Try clicking the javascript buttons to see the sequence on the schematic.

https://www.pjrc.com/store/ic_mkl02_t4.html

The question you asked was "if I remove the bootloader IC, can ... run existing program?" To conclusively answer *that* question: if you have other circuitry to detect stable 3.3V and assert DCDC_PSWITCH, then yes, your board should be able to run the existing program without the bootloader chip.

But perhaps the question you really are trying to ask is whether you can reuse the bootloader chip to program another board, after you've removed it from the first which no longer needs it. The answer would be no. The bootloader chips assigns the unique Teensy serial number and ethernet mac address, and in the process it permanently pairs with that particular IMXRT processor. It will not program another IMXRT processor.

 

[chensx2012]

But perhaps the question you really are trying to ask is whether you can reuse the bootloader chip to program another board, after you've removed it from the first which no longer needs it. The answer would be no. The bootloader chips assigns the unique Teensy serial number and ethernet mac address, and in the process it permanently pairs with that particular IMXRT processor. It will not program another IMXRT processor.

Paul, you are correct about my real question. I am definitely willing to buy your MKL02 chip to design my hardware products, and the price is totally fine with me. My concern is that someday your MKL02 IC for Teensy 4.x might be discontinued and I cannot buy it anywhere. But my products may last for quite a long time. In that case, what should I do?