Hello I'm building my first breadboard SamD21 As used in the arduino zero board. I pretty much have everything build for the breadboard friendly, I'm just missing the 10pf Capacitors that goes on the Crystal side.
So my question before i do the first bootload burn I'm wondering how necessary are those Capacitors needed for testing Just to get a simple blink led running?
P.s.s I have bootloaded other 32bit processor the same one on the arduino Due. But I was with a group of people when that happen. This will be my first bootloading on my own.
They are only needed if you want it to operate properly. Capacitors are used for a reason and if you do not understand why best not to mess with them. Since it is your board did you take into account the capacitance on your board?
Without them, the oscillator may not start, which means the CPU has no clock source and hence does nothing. Does the SAMD21 have an internal RC oscillator? You could use that for time being until your capacitors arrive.
Btw 10pF sounds a bit small; usually it's something like 18-33pF.
I have some on the way. But at the moment they are 2 days away. The D21 has a internal oscillator I do not know how to access it. That is something in never got into.
Edit: I did just now mange to find this to go crystaless here.
There you go, give it a try. Won't hurt.
I occasionally run a microcontroller on its internal oscillator during assembly and/or if I suspect there may be a problem with the external crystal circuit.
They are the sort of thing where if you don't fit them it might work OK, or it might seem to work OK but you then spend ages trying to fix weird and apparently unrelated problems.