Teensy 3.1

19 Nov 2015

Dear Mercury Waters,

Could you send to me@ikravets.com your `".pioenvs/teensy31/firmware.hex"`? Or share somewhere... Thanks.

Regards, Ivan Kravets

21 Nov 2015

Dear Mercury Waters,

Thanks! I've just re-tested your HEX (which I received via mail) and it blinks without problems.

However, I found a strange behaviour of Teensy board. The reset button breaks Teensy bootloader (edited: not breaks, see comment below). I have this issue not only with `teensy_cli`, but also with `Teensy.app`(Mac OS X). Only the "Reset"(Soft) button in Teensy.app makes REAL reset and board works good.

What you can try?

1. Run `platformio run -d examples/mbed/mbed-blink -e teensy31 -t upload` 2. `teensy_cli` will ask you to press "Reset" button, like: "(hint: press the reset button)". Please press "RESET" button, but only the one time. DON'T press second time.

Have it helped you?

21 Nov 2015

The 'Prog' button on the Teensy will not reset the MCU. Pressing this dumps a bootloader code from the interface chip into the MCU RAM that then operates with the Teensy bootloader program (apparently). The only way to reset the MCU is to press the 'Prog' button then select the 'Reeboot' button on the Teensy loader program. Or power cycle the Teensy or hardwire a switch connection to the nRST pad on the bottom of the Teensy board to GND. Hard reset works best.

21 Nov 2015

However, you can trigger the Teensy bootloader from software by issuing a "bkpt" processor instruction.

Teensyduino comes with an example in the usb_dev.c file:

void _reboot_Teensyduino_(void) { asm volatile("bkpt"); }

21 Nov 2015

Dear Paul Staron and Jorg Bliesener,

Thanks a lot for your explanations. However, this text from teensy_cli sounds unclear for me "(hint: press the reset button)" and I aspect another behaviour. Of course, I see the log... "Soft reboot is not implemented for OSX"...

Regards, Ivan Kravets

22 Nov 2015

Hi Ivan,

I tried exactly the same, again, and I made sure that I do not accidentally press the reset button more than once. It still does not work for me. I have not been able to setup gcc-arm yet on my mac, yet so don't know if it works from that route or not. I will try to setup platformIO on my Windows 10 and Linux and will let you know the results.

Shine On!

24 Feb 2017


I'm working with Tensy 3.2 and working now with SPI Master and Slave. The SPI Slave is not working properly :

Master is Teensy 3.2 and Slave also with same pin SPI : MOSI=PTD2 MISO=PTD3 SCLK=PTD1 SSEL=PTD0

SPI MODE=0 for both and frequency=1MHz. What's wrong is : When Master drive SSEL low, the pin MOSI from Slave is running low. The signals MISO_S_Fil and MOSI_S_FIL are only connected to the Logic analyser and coming from SPI Slave. What's coming from SPI Master and is connected to SPI Slave is CS/, SCLK.


The same C code is working well when I swap each teensy with two LPC1768.

Thanks in advance to have a look, and hope to see Teensy working with SPI slave.