Arm Mbed OS support forum

Custom Targets and MBED Studio with Teensy

It has been some time since I developed using Mbed. In the past I was using a Teensy 3.2 which was supported initially by Mbed and the hardware vendor PJRC. However as time has gone by it seems the hardware has become sidelined and now the hardware vendor does not support Mbed.

I was hoping to use Mbed Studio and try building for this board as a custom target and using baremetal mode, to avoid too many driver problems.

I was amused to find that the mbed online examples of ‘custom targets’ actually references the Teensy 3.1 in all its examples. This gives me the impression that this must have been used internally at Mbed to prove out the custom target functionality.

I have tried to get this board compiling in Mbed Studio, but without success. I tried simply modifying the target libraries (not to completion) but simply to prevent the compiler complaining about unknown symbols etc. I then did a little mod to the scatter file for the MK20DX256 to try and satisfy the stack and heap definitions which are now required by the compiler.

Without a great deal of digging, I did finally get something to compile and then programmed the .hex file into the Teensy…Nothing. Can even get a blinky to work or for that matter some simple serial comms over UART.

My longer term aim is to make used of Mbed to develop for PJRCs newer Teensy 4.0 board, but at the moment I’m a little frustrated, I have libraries and code which I wrote in Mbed for the Teensy 3.2. These are clearly going to become useless without some considerable re-working and to add to this there is no support at all for the Teensy 4.

It would be easy for me to simply move over to Arduino where all this hardware is supported, but I have invested time in Mbed and I like what is happening with the platform.

Can anyone give me further guidance about.

  1. Getting Teensy 3 to compile successfully in Mbed Studio
  2. Consideration for building support for the Teensy 4 ( with a minimal baremetal profile) within Mbed Studio.

All the best