Designing an AVR128DB48-based board

Other Hardware Hardware Development
1

Looking good so far

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User selectable voltage and clock circuit
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  • Have you considered using a 5v buck converter ?
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For what?

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  • I was assuming the two chips above the power plug were low dropout regulators.
    If so, the 5v regulator could be a SMPS circuit allowing more output current for peripherals.
5

I might implement that on V2, V1 has a priority on making sure it works

6

  • Let’s see the traces on the bottom of the PCB.

  • Suggest you avoid GND pour on the component side.

7

:face_with_peeking_eye:

uh-oh

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  • GND pour on the top of the PCB is not warranted.

  • You have very long traces that are cutting the bottom GND plane.
    You should: avoid these, add strapping on the top, or zero ohm resistors across them on the foil side.

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9

The bottom pour is not a gnd plane

Even the official Uno has a pour on both top and bottom, and no straps. Why is that?

10

The bottom pour is not a gnd plane
It should be a GND copper pour.
Provides the signal return paths for the top traces.

Even the official Uno has a pour on both top and bottom, and no straps.
Poor design on their part.

Why is that?
Straps over bottom traces correct contorted signal return paths.

  • Watch this YouTube video, pay attention to time around 40 minutes.
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11

What if the top is the GND pour?

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  • The above video goes into that.
  • Also, watch this:
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Hi, @outbackhut
Engineers solution;

solution
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It would be great for R&D.
If the first configuration didn't work with one controller topography, just twiddle a few knobs and change the conditions.
Non-Volatile Memory.
Tactile adjustment system.
With proper handling 1V8 to 180V operation.

Tom.... :smiley: :+1: :coffee: :australia:

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14

Dare I ask what solution this is solving? :rofl:

15

  • Design low noise PCBs by adding a ground plane on the bottom side.
    This ground plane should be unbroken by bottom traces.
    If traces must be on the bottom, keep them as short as possible and add a top side strapping so return signal currents are not interrupted.

  • Now you are an expert. :+1:

Here is one last video you should watch.

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  • Thought you were told to get into the medical line of business. :roll_eyes:
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17

What's the dig deal, looks like another Uno but with an SD card slot

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This board is:

  • Modern AVR core

  • Hardware secure element (keys that cannot be extracted)

  • Temperature-compensated RTC with ppm-level accuracy

  • High-resolution power monitor for real energy profiling

  • Separate internal and external I²C domains

  • Dedicated SD SPI bus (not shared with shields)

  • Cryptographic identity + signing capability

  • Designed around low-power operation and measurement

19

Can it run from a single Li-ion battery?

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V1.0 doesn’t have a lithium charger on board, but V2.0 will.

Irregardless, yes, it will run off a decent sized battery (2000 mAh or more) for a decent amount of time. Exact time will be calculated once the board has progressed past R&D