MSP432 LPM3 GPIO interrupt current consumption

Albert Lu1

Other Parts Discussed in Thread: ENERGYTRACE

Hi All,

Does anyone know the current consumption of the MSP432 in LPM3 while a GPIO pin is set to trigger and wake up from external voltage? (I know this is easy to measure, but my board is dead, but more are on the way.)

Thanks,

Albert

over 11 years ago

0 Robert Cowsill over 11 years ago

Guru 16361 points

Table 5-8 on page 21 of the datasheet has current consumption specifications for LPM3. Does your application not match the test conditions for those values?

0 Albert Lu1 over 11 years ago in reply to Robert Cowsill

Intellectual 520 points

I measured about 100~120uA using Energytrace and shunt resistor(8.2ohms) method. In the shunt method, I powered it with a 2.5F super cap.

0 Albert Lu1 over 11 years ago

Intellectual 520 points

It turns out EnergyTrace cannot measure LPM3 current correctly. The JTAG switch has to switched over to Ext debug, which disconnects the debugger. Once I did that, the current measured while one GPIO is set to trigger was around 3.3uA.

0 Robert Cowsill over 11 years ago in reply to Albert Lu1

Guru 16361 points

Did you already try using EnergyTrace (not EnergyTrace+) in "Free Run" mode? I think the results from that should be similar to those with the debugger disconnected in hardware, but it's a bit more convenient to use.

0 Albert Lu1 over 11 years ago in reply to Robert Cowsill

Intellectual 520 points

So I just tried Free run, and it reported .034mW. While it's still running, I unplugged the jumper on 3v3, and used it to power another eval board that (exact same code) had every single jumper removed, with JTAG Switch set to EXT. With this setup, I measured 0.012mW, which works out to be about 3.6uA. So I guess if you really want the exact value, you'll have to use one board to power and measure another so that you can set the JTAG on the 2nd to EXT, while EnergyTrace keeps reporting.

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MSP432 LPM3 GPIO interrupt current consumption