4 years, 10 months ago.

why DEVICE_SEMIHOST set to 0?

It looks like that C027 has the mbed chip, so why in device.h "#define DEVICE_SEMIHOST "? This prevent to have access to mbed_interface_powerdown and other mbed interface related functions preventing using any Deep sleep or power down mode waking back from and interrupt. Is there any way to get a library including the semihost functions?

Question relating to:

The u-blox-C027 is a complete starter kit that allows quick prototyping of a variety of applications for the Internet of Things. The application board has a MAX-M8Q GPS/GNSS receiver and ...

1 Answer

4 years, 10 months ago.

The semihost is only used by the original mbed interface chip, and not the one the u-blox has. It would actually result in a crash if it is activated for your target when trying to enter deep sleep.

The problem is that it always will start up even with the chip on the u-blox in a kinda of debug mode, which prevents it from properly entering deep-sleep, and from ever exiting it. On many other boards you can either cut a track between interface chip and the MCU (and replace it with a jumper) or not power the interface chip. But I don't know if the u-blox has such an option.

Accepted Answer

On the C027 the interface chip is only powered only by usb. You don't need to remove a jumper or cut a wire, just un-plug the USB of the mbed interface.

posted by Michael Ammann 28 Mar 2015

Tnx, guys. Anyhow, this looks like not helping me. Sleep mode is working perfectly. From deep sleep it doesn't wake up by EINT1 (or 0..2 or any other IRQ). I supposed "... due to limitations of the Cortex-M3 integration, the LPC17xx cannot wake up in the usual manner from Deep Sleep and Power-down modes. It is recommended not to use these modes during debug." (From NXP LX17xx UM). I was assuming that was due to mbed interface to be disabled, now per your answer Michael, I assume that unplugging from USB it should work. Actually, it doesn't. So, considering that interrupt are enabled (it works in sleep mode), where could be my mistake?

posted by Roy Batty 28 Mar 2015