Vladimir Pouzanov

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10 years, 8 months ago.

0201 firmware issue — USB disconnection after copying the new binary

I've flashed the mbed firmware on my kl05z board and I have a small issue with it. Every time I copy over a new binary, the USB reconnects, which makes OS X unhappy, throwing warnings about unsafely ejected device in my face.

I remember the same issue happening with original lpc1768 mbed board, which was fixed later, can the same fix be applied for kl05z?

Question relating to:

Last updated: 27 May 2019
The FRDM-KL05Z is an ultra-low-cost development platform enabled by the Kinetis L Series KL0x MCU family built on the ARM® Cortex™-M0+ processor. Features include easy access to MCU I/O, battery-ready, …

1 Answer

Neil Thiessen
10 years, 8 months ago.

If the FRDM-KL05Z is anything like the FRDM-KL25Z, this is probably not going to be fixed. The reason being that the official mbed boards have an onboard flash IC that's used for LocalFileSystem and storing firmware images. When you press Reset, the interface chip checks for the newest file, and if it's different than the last one that was flashed it re-flashes the microcontroller before resetting it. The FRDM boards don't have this IC however, so the interface chip flashes the microcontroller immediately after a file is copied, and then resets itself. If I recall correctly, OS X Mavericks only pops up a notification if a device is removed without being ejected, so it's less annoying than previous versions of OS X that popped up a big fat dialog that had to be dismissed. For me personally, the more annoying part is that the serial port disconnects as well, so on Windows I have to restart Tera Term every time I re-flash...

Alt+I, alt+n, <enter>, alt+b, that resets serial in TeraTerm :). (well assuming with a new connection it selects the correct port automatically, it does for me, but then that is the only active one I got).

Embedded Artists have a firmware version for the LPC1549 (or something close to that), which only resets the USB MSD stack, and keeps the USB Serial stack running, solving the serial issue, not available for the KL05 yet though. And the problem for the USB MSD part is indeed since there is no flash IC, it requires an eject to force the OS to re-read the contents of the flash drive.

posted by Erik - 31 Mar 2014

Thanks, that makes sense. That's not really that annoying, broken CMSIS-DAP is a bigger issue :-)

posted by Vladimir Pouzanov 31 Mar 2014

I believe this will be fixed in the next CMSIS-DAP revision.

posted by Martin Kojtal 01 Apr 2014