Interface Powerdown

Page last updated 13 Oct 2010, by   Simon Ford   No tags | 5 replies  

This note discusses an experimental (== unsupported) mbed interface firmware version which allows you to instruct it to power down. This has the effect of disconnecting the interface as a debugger and disabling the USB interface.

The semantics are:

• The target can make a semihosting call to the interface to request it to power down
• If USB is not connected, the interface will detach its debug connection to the target, then power down
• If USB is connected, it will be ignored and the mbed will function as normal
• The interface will be restored again after a power cycle

The experimental firmware is at:

• mbedMicrocontroller_ExperimentalPowerdown.if

To load it, drag it on to your mbed and power-cycle. If you want to revert to the standard firmware at any time, go to /handbook/Firmware.

To request a powerdown, take a look at the example program:

• semihost_powerdown

Note, as the call is ignored when USB is connected, you can always plug in your mbed and reprogram it as normal.

5 comments

Dean Bell

# 19 Dec 2010 . Edited: 19 Dec 2010

Dose the new boot loader put IC1 it into

• Sleep
• Deep Sleep
• Power Down
• Deep Power Down

when  "__semihost( USR_POWERDOWN, &arg );" is called?

I also note that " #pragma NOINIT" & " #pragma INIT" don't work with the compiler. When trying to store vars for watchdog trace back.

#define WDG_LINE() (wdg_line = __LINE__)

#pragma NOINIT
uint16_t wdg_cnt;
int      wdg_line;
#pragma INIT

Philips Philips

# 22 Jul 2011 . Edited: 22 Jul 2011

Did this ever get added to the main libs, if not how can I make a lib out of the expermental lib

Philips Philips

# 23 Jul 2011 . Edited: 23 Jul 2011

I see __IO uint32_t PowerDown;  and that's it... what am I supposed to be looking for...........

Hirofumi Inomata

# 28 Jul 2011 . Edited: 29 Jul 2011

Can no anyone can wake up from DeepSleep by any InterruptIn? While, sleep works right and, wakes up by an interrupt.

jim hamblen

# 07 Oct 2011 . Edited: 07 Oct 2011

I seem to be able to reset from DeepSleep using the watchdog timer - see http://mbed.org/forum/bugs-suggestions/post/14029/

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