I was wondering if anyone knew a way to reduce the power consumption of the chip.
Right now we put the radio link to sleep whenever it's not in use and then wake it up when whenever we use it. Also, we don't use the LED lights when we don't have to (although I don't know how much power that saves). Are there any other things we can do to use less power while running the chip.
Turning off as much peripherals as possible when not in use will lower the current consumption. To estimate the current consumption for the MSP430, the device datasheet lists numbers for each operating mode with certain frequencies and operating voltages. Additionally each peripheral's current consumption is listed separately in it's corresponding section of the datasheet. Adding these values as needed can give a good estimate on current consumption but experimental testing is needed to determine the actual consumption your peripheral configuration will exhibit in the field.
We have a couple of related k-base articles on this which you may find useful:
1.
http://www-k.ext.ti.com/SRVS/CGI-BIN/WEBCGI.EXE/,/?St=26,E=0000000000014017023,K=2246,Sxi=12,Case=obj(37929)
Hint:It is good design practice to connect an unused Test/Vpp pin to Vss(GND). If this pin needs to be routed to the JTAG-connector for debugging, an external pull-down resistor will improve EMI/EMC performance.
http://www-k.ext.ti.com/SRVS/CGI-BIN/WEBCGI.EXE/,/?St=26,E=0000000000014017023,K=2246,Sxi=12,Case=obj(51373)
Problem:Why is the supply current higher than expected especially in low power modes?
-->Why is the supply current higher than expected especially in low power modes?
Solution:
Solution:MSP430: Current consumption is high in Low Power modes -->
A few things to check for low current consumption are: a) All unused I/O pins must be left open,
switched to port function and their direction configured as outputs. The correct termination of all unused pins is listed in the
Connection of Unused Pins section of the System Resets, Interrupts, and Operating Modes chapter of the device user`s guide.
a) Is the ADC reference turned off? Please see Datasheet
b) Is the comparator turned off? Please see Datasheet
c) If using XT2, is XT2 turned off?
d) Verify the connections on MSP430’s inputs even when in LPM mode?
e) Is the device clean (flux, unwanted solder)?
Great! Thanks a lot for this!
Hi,
I'm looking for the Timer_A (and Watchdog) power consumption. I didn't find anything in the datasheets.
I'm using MSP430F1612 and MSP430F2274.
Could you tell me where is this information (page number) ?
Regards
Romain
RomainI'm looking for the Timer_A (and Watchdog) power consumption. I didn't find anything in the datasheets.
the power consumption of the timers isn't speced because it doesn't add a significant power adder to the base currents speced and they're usually assumed to be on during low power modes like LPM3. timer functions are basically "free" from a power perspective.
Ok for a low power application, but I'm working on very low power application (10 years autonomy).
I thought about using the watchdog in LPM3 instead of using timers in order to reduce the current (with all others peripherals OFF). Is this a good idea, or is there any difference ?
In this case, I would change for an external power system shutting off the MSP430.
Thank you !
Romain Ok for a low power application, but I'm working on very low power application (10 years autonomy). I thought about using the watchdog in LPM3 instead of using timers in order to reduce the current (with all others peripherals OFF). Is this a good idea, or is there any difference ? In this case, I would change for an external power system shutting off the MSP430.
Romain,
in terms of power consumptions, you won't see a difference between Timer_A/B or the WDT. If the WDT does what you need and you just need a basic interval timer, then use it. You'll get a bit more functionality out of Timer_A/B but if you don't need those extra features then any of the timers will be fine.
What kind of duty cycle (Active time vs Sleep time) are you expecting for your application? 10+ year battery life isn't uncommon for 430 apps.
Thank you Adrian,
I'll use one timer (B) clocked with ACLK in active and sleep mode. I'm working on Wireless Sensor Network, the duty cycle is variable between 0.1 and 3sec, so I must have a consumption model to simulate the network life.
If, one day, you find currents of the peripherals, i'm still interested ! [;)]
I'm also making battery supplied sensors with long lifetimes (>10 years). I'm using an MSP430G2433 and my total budget is 3uA. with 3.6V supply, I could measure about 400nA consumption for one Timer_A at 32kHz. If I use both Timers, I come to 0.8uA. This represents 26% of my total budget.
So I'd be very interrested in typical and maximum Timer consumption values.
Regards,
D. Blanc