Heltec CubeCell - part 1

It would be nice to add a comparison between the different CubeCell products so one can select a board based on requirements.

HTCC-AB02S product page Overview says:
Ultra low power design, 50uA in deep sleep;

HTCC-AB02S product page Tech Specs says:
Low power design Deep Sleep 3.5uA

Apparently the 50uA in the Overview is correct and 3.5uA is uncorrected copy/paste?
Why is deep sleep current 14+ times higher than for the other CubeCell boards?

the deep sleep current is higher because the GPS needs so much current even in sleep.

That is what I suspected. Are those 46uA during deep sleep needed to keep GPS state e.g. for hot start?

There should be an option to power-off/on the GPS if the user so desires so it can be disabled during deep sleep when GPS is not always needed (similar to why VExt was added).

Sorry, that’s a mistake, fixed now.

Because the sleep current of the Air530 GPS module used is about 20uA, plus other peripheral circuits (mainly diodes), there are nearly 20uA, plus the current of CubeCell, so the sleep current is ~50uA

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So no option to power-off GPS (etc.) when not needed?

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Is the stated 3.5uA deep sleep current for HTCC-AB02 (not AB02S) correct?
Can the display be fully powered off or is true deep sleep current of the board higher than 3.5uA?

Brief overview of the new ASR6502 based CubeCell boards

  • CubeCell 1/2AA Node (HTCC-AB02A)
    This is the most basic version of the three new ASR6502 based boards.

    Features that the other ASR6502 based models do not have:

    • SMA antenna connector (instead of U.FL/I-PEX connector)
    • 1/2 AA size Lithium battery holder.
    • White PCB while the others have black PCB.
    • Does not fit on a breadboard due to IO25,26,27,28 pins and battery holder.
      Workarounds: 1) use pin header extenders, or 2) remove (desolder) these pins and holder.
  • CubeCell Dev-Board Plus (HTCC-AB02)
    Similar to HTCC-AB02A with added:

    • RGB LED
    • Display
    • Solar Input
    • Fits on a breadboard

    Comparable to HTCC-AB01 but with display and ASR6502 with more IO ports and additional SPI.

  • CubeCell GPS-6502 (HTCC-AB02S)

    • Like HTCC-AB02 with added: GPS
    • RST and User buttons are operated from the top instead of from the sides.

Note: The boards have different pinouts.

Preference: I would have liked USB-C instead of microUSB connectors.


for the HTCC-AB02A:

if you dont need the SPI pins you can use pin header expansions for using it on a breadboard.
If you design your own PCBs you can use long female pin headers.

Yes that is a good and non-destructive option.

Those SPI pins used for LoRa should not be needed anyway (unless needed for measurements) and ASR6502 has a second SPI port if SPI is needed.

My first CPU was a MOS Technology 6502 (second-sourced by Rockwell).

So the ASR6502 feels like some kind of Déjà vu. :smile:

A long time ago my first was a
Zilog Z80A @ 4 MHz
In a schneider cpc

10 years after your 6502

Yes, the GPS module powered by a MOS-FET Q3, so it can be turn off when don’t need.



Yes, the HTCC-AB02 is almost exactly the same as HTCC-AB01, the same core, and the same LoRa chip, just more resources, the OLED display use Vext power, it can be fully turn OFF.

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how much current will the GPS chip draw when VGPS is turned off?
i see that the VBACKUP is always connected.

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what i dont understand is why the three new boards have all different pinouts.

it would be great if i can use the dev board plus for some node and when i need gps i just swap it with the GPS-6502

Now i have to produce different PCBs for each board.

and please use USB-C for the next generation.

Have not tested this data, the VBACKUP is a Farah capacitance.

If turn off GPS, it will take a long time to acquire satellite signals.

Makes sense! Unfortunately we didn’t hear your thoughts early… :upside_down_face:

Probably because you haven’t asked. :wink:

This topic is continued here: Heltec CubeCell - part 2