From 1f3b8e7b216507f4bcbb65712013cba3e2c9d39c Mon Sep 17 00:00:00 2001 From: Daniel Friesel Date: Fri, 4 Dec 2020 15:43:47 +0100 Subject: add comments on the inner workings of the msp430 energytrace library --- bin/msp430-etv | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/bin/msp430-etv b/bin/msp430-etv index 9700c66..560bd2c 100755 --- a/bin/msp430-etv +++ b/bin/msp430-etv @@ -645,12 +645,19 @@ def main(): bin_count = args.histogram + # On an MSP430FR5994 launchpad, energy is measured and reported with a + # granularity of 200 / 300 / 400 nJ per pulse. Details are unclear. plt.title("EnergyTrace Data Analysis") plt.xlabel("Reported Energy per Measurement Interval [J]") plt.ylabel("Count") plt.hist((data[1:, 3] - data[:-1, 3]) * 1e-9, bins=bin_count) plt.show() + # Data is transferred using a URB_BULK endpoint with five samples + # per USB packet. There's about 1.4ms between consecutive packets + # and 210 to 270 ms between most consecutive samples. The first sample + # in a packet typically has a larger delta-t of ~400ms vs the last + # sample in the previous packet. plt.title("EnergyTrace Data Analysis") plt.xlabel("Measurement Interval Duration [s]") plt.ylabel("Count") -- cgit v1.2.3