8Bit or 32Bit processors

[NeverDie]

Anyone else here tried the Sparkfun SAMD21 board? So far, I'm having trouble getting it to upload a new sketch.

[Nca78]

@NeverDie said in 8Bit or 32Bit processors:

@NeverDie said in 8Bit or 32Bit processors:

It should be using one of these cables instead: https://www.adafruit.com/product/1675

Argh. I hadn't really noticed before, but the pitch (1.72mm) on the SWD connector specification is much smaller than what I'm used to. In addition, the Sparkfun board arrived, and it came with no pins installed (actually no pins at all) for the SWD. It would require a special order for 1.72mm pins from I'm not sure where.

Order a set of pogo pins and make yourself an adapter PCB maybe ?

[NeverDie]

@Nca78 said in 8Bit or 32Bit processors:

@NeverDie said in 8Bit or 32Bit processors:

@NeverDie said in 8Bit or 32Bit processors:

It should be using one of these cables instead: https://www.adafruit.com/product/1675

Argh. I hadn't really noticed before, but the pitch (1.72mm) on the SWD connector specification is much smaller than what I'm used to. In addition, the Sparkfun board arrived, and it came with no pins installed (actually no pins at all) for the SWD. It would require a special order for 1.72mm pins from I'm not sure where.

Order a set of pogo pins and make yourself an adapter PCB maybe ?

That's a good suggestion. However, I think I may just solder the four key wires directly to the board, because presently I'm viewing the Sparkfun board as just a proof-of-concept and a test of whether or not it's ready for prime time. If that works out, then I plan to shift into making some specialized DIY nodes based on the same SAMD21..

[NeverDie]

I found my error. It turns out there's an Arduino board definition file for the Sparkfun SAMD21 mini. Once I installed that, sketches upload, verify, and work fine, although I do still get a mysterious error message "An error occurred while uploading this sketch." Meh, at least so far it doesn't seem to matter.

So, thinking about this a bit more, I think a good next step might be making a minimalist SAMD21 pro mini, but using the TQFP32 instead of the TQFP48 that sparkfun uses. I'm hoping that the TQFP32 will be easier to solder. The resulting board may not turn out to be 100% equivalent, but it will be interesting to see what the trade-off is, if any, that led Sparkfun to go with the TQFP48.

[tbowmo]

@NeverDie

Perhaps they need the extra pins that are available on the tqfp48? Can't remember if there is an additional sercom device in the 48pin, or if it's first available int he 64pin variant... But that might also be the reason why they chose to use that device..

[NeverDie]

Looks like my assumption was wrong. Delving into it more closely, I suspect the TQFP64 will be the easiest to solder. Why? Because the pin-to-pin pitch on the TQFP64 is 12mm, whereas on the TQFP48 it's 9mm, and on the TQFP32 it's only 8mm. At least to me, the solder bridges--and the alignment of pin-to-pad-- I get when the pin spacing is too close is what makes the soldering hard on these SMD's.

Scratch that. It didn't make sense. I was looking at the wrong dimension. The pitch on the TQFP64 and TQFP48 is 0.5mm, whereas on the TQFP32 it's 0.8mm. So my assumption was correct after all.

[Nca78]

@tbowmo said in 8Bit or 32Bit processors:

@NeverDie

Perhaps they need the extra pins that are available on the tqfp48? Can't remember if there is an additional sercom device in the 48pin, or if it's first available int he 64pin variant... But that might also be the reason why they chose to use that device..

4 SERCOMs on the 32 pins instead of 6 on the 48 pins.
10 ADC channels instead of 14 (and 20 on the 64 pins)
10 * 6 X&Y lines on the touch controller instead of 12 * 10 for 48 pins and 16*16 for 64 pins
64 pins also have 5 Timer Counter instances, it's 3 on 32/48 pins

These are all the differences (with of course different number of GPIOs),, everything else is similar in the datasheet.

[lafleur]

@Nca78

1.27mm headers 5x2 (.05in) Mouser 855-M50-3500542 made by Harwin

[NeverDie]

So as not to derail this thread, I've started a new thread here: https://forum.mysensors.org/topic/6961/minimalist-samd21-tqfp32-pro-mini
for further discussion related to the SAMD21.

[Nca78]

@scalz said in 8Bit or 32Bit processors:
Arrow.com is nice too as it's 20€ minimum order for getting free express shipping ;)

Just received my first order today, delivered only 4 opening days after order in Vietnam, and ... no taxes not even VAT :D
In total i ordered 12 SAMD of 3 kinds, a few atsha and some 0603 ferrite beads my local sellers don't have. I was a bit surprised to see a 505010cm box. But then when I opened the box I understood. This is the packaging for 4 ATSAMD20: carton box containing a giant antistatic bag containing 2 plates made for 260 MCUs each and only 4 in the middle. Missing on the picture is the bubble wrap that was around the antistatic bag.
Packaging for other parts was not that delirious but still excessive imho, I guess they're not trying to be awarded a green label :D

In the end a very positive experience: reasonable prices, not cutting corners on packaging, great express shipping (now I'm sure I'll never use DHL again...). I just need to buy another apartment for storage before I make a new order :D