Hi Kelly,
The MSP430 usually runs as low as about 1.2V at 1MHz. At 1.4V is is rock
solid, which is why the brownout reset operates at 1.4V. That said, if
you are in LPM3 or LPM4 neither the CPU or the 1MHz clock is running, so
they consume essentially no power. The usual reason for the type of
problem you see is that you have not turned off some power hungry
peripheral before entering the low power state. The ADC or its voltage
reference would be good candidates. Perhaps they just give up and stop
consuming below 1.6V, so you see a change there. I am not sure. High
consumption through some port pin is another possibility.
Good thing: The MSP430 peripherals have a *lot* of options you can choose.
Bad thing: The MSP430 peripherals have a *lot* of options you can
choose. :-)
There are a lot of registers to check through and get just right to
achieve the best results in low power mode. You should be running at
around 1uA if everything is right. If you have everything set up
correctly you *will* achieve that current. You really need to measure
your current consumption as you go into low power mode. A lot of strange
things often occur, taking short bursts (a few seconds) of significant
current as all the voltages from all mains powered circuitry interfaced
to the MSP430 dies away (e.g. I/O pins slowly dropping through the
switching region of their inputs consume over 100uA each).
Regards,
Steve
Kelly Murray wrote:
Mclk is 1Mhz, Aclk is 32khz, as I said, it DOES turn the power back on
when I provide changed input. I've confirmed it's caused by the MSP
since
I changed the watchdog interval from 1 to 4 seconds, and it then takes
4 seconds
to wake up instead of 1.
nobo...@web.de wrote:
Hi,
I think the specs say 1.8v. However, it does still seem to be
running, because it is still monitoring
the input and turns the power back on.
at 1.8 V the MC hangs with more than 4.15 MHz clock.
You should check that.
Rolf
