Drew Folta

Member Since: September 30, 2012

Country: United States

  • The RTCZero standbyMode() actually puts the device into standby mode (also known as deep sleep). Here’s its implementation: https://github.com/arduino-libraries/RTCZero/blob/c481302b6812a139d59eeb5da7d2a4cc4eefa73d/src/RTCZero.cpp#L133 For my project I have both TC4 and TC5 configured with RUNSTDBY so that they continue running during standby. Section of the SAM D21 datasheet has lots of details.

  • Makes sense. The trick with this product is that it’s not an arduino zero clone (the pins and sercoms are slightly different) so platformio might have a little trouble incorporating it. Regardless, it’s up to them to figure this out :) (Hopefully they have a tool to generate their configs from the arduino boards json.)

  • Is there any plan to add this to platformio? It looks like the following file will need to be updated: https://github.com/platformio/platformio/blob/develop/platformio/boards/sparkfun.json (Hmmm… it’s probably more complicated than just updating that file…)

  • Will this power an ESP8266?

  • I did some playing around. With the power LED, SerialUSB.begin(9600), and attachInterrupt(9, cb, HIGH) I saw about 17.1mA. When I then use that interrupt handler to turn on the builtin LED (arduino pin 13) I saw about 20.3mA.

    I then added EIC->WAKEUP.bit.WAKEUPEN7 = 1 so that arduino pin 9 could wake the device from deepsleep. I also used a copy of standbyMode() from RTCZero library for putting the device to sleep. With all that I got the device to sleep then wakeup when pin 9 went high. Otherwise same setup as above, and with the builtin LED off I saw about 8.3mA and about 11.6mA with it on.

    Then I cut SJ1 on the back to disconnect the power LED. While sleeping, I saw about 1.3mA with the builtin LED off and about 4.8mA with it on.

    Interpretations. Looks like the builtin LED uses about 3.2mA and the power LED uses about 7mA. Looking at the SAM-D21 datasheet it looks like deepsleep could be made more efficient by turning off or slowing down the peripheral clocks, but at 1.3mA I’m super happy and likely won’t bother with that.

    Major caveats: I’m a beginner. My multimeter is cheap and likely not very accurate. BTW, I had trouble waking the device from sleep to program it, so I wired in a second digital pin to disable sleep :)

  • Oh hmm… SERCOM0/PAD2 should probably also be “D8” (it’s PA06, page 21 of datasheet).

  • I think you have a bug in your “SERCOM – Configurable Serial Ports” table for SERCOM2 PAD2. I think this should be “D2”, at least on the mini (probably for dev as well). The datasheet for PA14 (page 22) shows “SERCOM2/PAD[2]” and “SERCOM4/PAD[2]”. The schematic for the mini shows PA14 wired to D2.

  • I’m curious about the overhead/efficiency of the power regulation on board. Will this work if I plug a lipo (3.7-4.2v) into VIN? Does it have the same DC-DC converter and LDO voltage regulator pair that the Zero has?

    Basically I want to run this for 7 days from a 2500mAh lipo, which I think works out to an average current of 13mA. I’m hoping to make heavy use of standby mode to accomplish this, but I’m worried about “station keeping” components such as the regulator(s).

  • Scroll down – the first section of the second page shows this switch.

  • I think these are colored the same way as resistor bands: wire 1 is brown, wire 2 is red, wire 3 is orange, wire 4 is yellow, wire 5 is green, and wire 6 is blue. (I still think they should have started with 0-black though…)

No public wish lists :(