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High Current Draw With Floating Point Calculation

kenclark gravatar image

asked 2017-07-17 16:29:07 +0200

I'm attempting to optimize our application for battery life on the nrf52832.

If I execute a floating point calculation to rescale RGB to PWM, I start drawing 6.2mA, eliminating the calculation reduces current to an more reasonable 0.05mA. To be clear I am not using the calculation result to drive the PWM yet, just making the calculation & saving the result globally

volatile uint16_t blue_cmd; void rgb2pwm(uint8_t blue) { float blue_duty_cycle = (float)(blue)/2.55f; blue_cmd = (uint16_t)blue_duty_cycle; }

Is there something that needs to be done to minimize power for floating point calculations?

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joh2 gravatar image

answered 2017-07-17 17:04:18 +0200

Hi,

Make sure you have implemented the workaround for PAN-87 - CPU: Unexpected wake from System ON Idle when using FPU.

Best regards,

Jørgen

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That fixed the issue. Thank-you ken

Ken ( 2017-07-17 21:35:58 +0200 )editconvert to answer

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Asked: 2017-07-17 16:29:07 +0200

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Last updated: Jul 17