Itsybitsy M0 Express wasted potential?

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csva
 
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Itsybitsy M0 Express wasted potential?

Post by csva »

Great product!

I looked at the schematic for the "Itsybitsy M0 Express", and it has two unused pins. :-(

Why not use the bigger ATSAMD21J18, @ 9x9mm with 16 more GPIO pins? Price is almost the same. ( $2.80 vs. $2.67 in 100's) Alternatively the 5x5mm BGA @ $1.43 in 100's. Epoxy is expensive huh?
Internally the chips should be the same, so the boot-loader would have to activate the extra 16 pins.
See https://github.com/mirage335/ATSAMD21J18_ArduinoSupport.

It would not be so "itsybitsy" any more with potentially 16+2 more GPIO, +12 per side of PCB, (relocate the 5 odd end-pins to the sides), for a better fit into an experimenter plug-board. (~ 66mm long PCB . The board would likely have to be a few mm wider to break out those extra pins. Package is close: QFN50P900X900X100-65N). The debug connections could be on the short side for a less than 102mm long PCB maybe even the same pitch wiring as the Atmel-ICE?)

"The exposed die attach pad is not connected electrically inside the device". Page 844
The area under the chip could be used for traces and break out vias.. I doubt the metal pad needs to be fully connected, some smaller grounding spot may be enough for thermal conduction and/or shielding. Use 4-layer board and/or 0.3mm holes and 6 mil rules if needed. Looks like an afternoon layout job.
Last edited by csva on Sun Mar 18, 2018 5:27 pm, edited 1 time in total.

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Franklin97355
 
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Re: Itsybitsy M0 Express wasted potential?

Post by Franklin97355 »

The ItsyBitsy is a board form factor and so adding a bigger processor would not get you any more pins. If you added more pins it would no longer be an ItsyBitsy.

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csva
 
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Re: Itsybitsy M0 Express wasted potential?

Post by csva »

Sure that is what I implied.
Then call it something else. Who cares.
Itsybitsy-64PIN_M0_.png
Itsybitsy-64PIN_M0_.png (119.53 KiB) Viewed 305 times

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Franklin97355
 
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Re: Itsybitsy M0 Express wasted potential?

Post by Franklin97355 »

I'm sure someone will.

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