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Padi Stamp v2.2.1, v3.5 (2016/10/08-16:57:18)
#61
Pete is correct;  it looks messy, but its easy and painless. The shifter worked great! I have two uart(s) that need matching (orange yellow) and (green blue).  The shifter has another advantage ; you can connect your colors consistently at the source ( for instance orange Tx  and  green Tx ) and then switch the Rx--Tx at the shifter !  ... much less likely to make a Tx--Rx mistake. Anyway the SerialBlink5 code that I posted earlier works just fine on the Mega too... even though the Mega doesn't really have the current needs on 3v3, it still works because the padi only spikes to those current levels during wifi xmit, which is very short in my application ( robotics ).  In the final I will still use external power.

   

The shifter is in the middle ground left.  The ground and 5v are at the center, and the uart pairs are on the outside. Seen clearly are the uart lines from the Mega.  Again, this looks more messy than it is...  the hook-up diagrams on the Sparkfun site are very clear, and easy too.

   

This is the same scene from another angle;  the makershed shield provides (3) 3v3 outputs (on the right) and also (3) 5v outputs on the same plug port (right).  (grounds are in the middle)  ... this makes it very convenient for hooking up a shifter and providing the ground wires.  I discovered that the shifter has two ground pins ( connected together ) so that only one ground pin on the shifter is required. 

The good news is that the Mega works, and no blue smoke from the padi nor from the pine board !   Wink

Note: the reason it looks more messy than it is results from the fact that the shifter doubles the number of wires (jumpers) needed; which results in 11 connections to the shifter! Also, becuase of the strange mix of male and female headers, I needed about a dozen jumpers with female on one end, and male on the other. Its a good idea to have plenty of all three; M-M M-F F-F

Note: I was afraid the downside of flipping the padi down-side would be not being able to "see" the red|green TxRx LED(s) on the padi... no problema! ... the LED(s) brightly reflect off of the makeshield below !
marcushh777    Cool

please join us for a chat @  irc.pine64.xyz:6667   or ssl  irc.pine64.xyz:6697

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#62
   

This pic is the same Mega2560 with the padi;  the difference is that the shifter and the padi are both powered correctly from external source; seen background right.

The external source is powering both the 5v and 3v3 rails on the shifter, the common ground, and the 3v3 rail for the padi stamp.  The power is applied FRIST to the shifter and padi stamp, then the Mega2560 is booted.  This works quite well logically and electrically.

Yes, at some point here I'll provide the schematic ;  probably when I provide the telnet dialogue codes coming soon.
marcushh777    Cool

please join us for a chat @  irc.pine64.xyz:6667   or ssl  irc.pine64.xyz:6697

( I regret that I am not able to respond to personal messages;  let's meet on irc! )
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#63
   

I thought I could live without the power LED on the padi;  dkryder was right -- we really do need the power LED monitor on the padi stamp because sometimes the jumpers don't quite make, or we have a poor jumper , and the LED ( which I have changed to green here ) helps us know from just a peek where the problem is...

... thanks dkryder.

note: I moved the posts about the padi LED pcb error to its own sticky thread
marcushh777    Cool

please join us for a chat @  irc.pine64.xyz:6667   or ssl  irc.pine64.xyz:6697

( I regret that I am not able to respond to personal messages;  let's meet on irc! )
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