[NTLK] Designing an Internal WiFi Board for MP2x00

Jake Bordens jake at allaboutjake.com
Mon Feb 2 19:56:05 EST 2015

>I believe that the serial port runs a CMOS level which can go up to 5V. 
>Make sure that your module can take 5V at the input. Also, you may need a 
>3V-to-CMOS converter on the outputs.

So I've verified that the Serial3 signals are all 3.3v logic levels using 
the oscilloscope.  The Serial0 lines do get driven to 5v (I think by the 
LTC1323.  I think the signals from the uProcessor to the LTC1323 are 3.3v, 
its the LTC1323 that pushes 5v signals back to the uProc)

Incidentally, the WiReach module is NOT 5v tolerant.

>I highly recommend that you build a breadboard version first, but then 
>again, I am quite sure that you did ;-).

Yep :)  I needed to make sure I had the hardware flow control lines 
right-- which I always seem to screw up... and still might find that I 
screwed up again.  With this design, you can short the flow control lines 
at one of the debug headers, and cut a two traces to the Newton to bypass 
flow control.  (I wanted to be sure I had an avenue to do this, since in 
the past I screwed things up and had to do just such a thing.)

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