ConfusedCoder 0 Posted November 22, 2017 Share Posted November 22, 2017 Hi, I was working on interfacing my MSP430 with a 4x4 keypad and I stumbled upon this application report. Then I looked into the specific low power modes of the F5529 and noticed that there was a LPM4.5. The application report uses LPM4 as it isn't the same device, and I was wondering if it was possible to use LPM4.5 as the device was waiting for keypad input as my goal is to minimize power usage. Quote Link to post Share on other sites
dubnet 238 Posted November 23, 2017 Share Posted November 23, 2017 You would need to take a look at the documentation for the F5529 to verify that it can be awakened with a GPIO interrupt. In a very deep sleep, IIRC, the list of available interrupt sources gets shorter. So if LPM4.5 supports a GPIO transition as a wakeup source you should be good to go. ConfusedCoder 1 Quote Link to post Share on other sites
ConfusedCoder 0 Posted November 23, 2017 Author Share Posted November 23, 2017 7 hours ago, dubnet said: You would need to take a look at the documentation for the F5529 to verify that it can be awakened with a GPIO interrupt. In a very deep sleep, IIRC, the list of available interrupt sources gets shorter. So if LPM4.5 supports a GPIO transition as a wakeup source you should be good to go. On page 51 of the data sheet for the F5529, it states "Wake-up signal from RST/NMI, P1, and P2" listed under the Low-power mode 4.5 section. That confirms it as an option for what I'm trying to implement, right? Quote Link to post Share on other sites
dubnet 238 Posted November 23, 2017 Share Posted November 23, 2017 it would appear to be so. If you have the 5529 Launchpad it would easy to confirm. ConfusedCoder 1 Quote Link to post Share on other sites
terjeio 134 Posted November 23, 2017 Share Posted November 23, 2017 I have ported code from that application note to C, one version is available on github if of interest. I2C-interface-for-4x4-keyboard Terje Fmilburn and ConfusedCoder 2 Quote Link to post Share on other sites
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