Removing the Bootloader/ISP Programming

[htho]

Hi,

I am considering using the Teensy 3.1 for a Project.

For this Project I need to make sure, that there is no way to update the Firmware via USB. For AVRs I could remove the Bootloader and use an ISP, but I have no experience with 32 bit ARM Cortex-M4 Processors. How do I do this with the Teensy 3.1?

Best

htho

 

[PaulStoffregen]

You probably want to make your own PCB with just the MK20 chip. Teensy is designed to always allow reprogramming, so it can be useful for prototyping. When you want your design to be fixed and never changeable, you'll need to make a board without the Mini54 chip.

P&E Micro makes the most commonly used programmer for Freescale's chips.

The MK20 has a special option to lock the chip and permanently disable erase. Teensy tries very hard to never allow this to be set. But if you program directly with P&E Micro's programmers, you can set it. Once the chip is locked and erase is disabled, the chip can NEVER be reprogrammed.