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Fez Cerb 40 Pinout Cheat Sheet Attached


#1

Hey Guys,

I found myself switching back and forth between a printouts/screens and the board and counting pins etc, So I decided to make a 1:1 scale Pinout Sheet with some Pin Info for the Fez Cerb40 that aligns with the TOP of the board.

I’ve love some feedback and can make some changes additions etc and post an update. This file is version v0. Here’s a dropbox link: https://dl.dropboxusercontent.com/u/10786391/Fez%20Cerb%2040%20Pinout%20Sticker%20Label%20V0.pdf

Questions: Does Pin.PA5 map to Analog Channel 8…Currently It’s a “?” on the PDF.
Also, Are the other analog pins/DAC (NOT PA5 and PA4) 5v tolerant?
I’ve found some inconsistencies here regarding 5v tolerance and Analog Channels:
https://www.ghielectronics.com/docs/46/cerb-family
and here:
https://www.ghielectronics.com/docs/44/fez-cerb40-developer

Note:
*PWM_N is the PWM Channel Mapping Number
*ANLG_N is the Analog Channel Mapping Number
*The rest is from the documentation.


#2

I have my Cerb40 headers soldered in pointing UP so that when it’s on my breadboard the silkscreen is visible.

But your doc is great for someone who has it the other way up :slight_smile:

I would always say avoid 5v on an ADC input. Even if it’s tolerant you can’t read it, better to design your circuit to not go over that. (IIRC the common issue is not with the ADC itself, it’s the multiplexer in front that is more sensitive).

(V2 suggestion, make a second copy with the columns reversed for the “alternate” view :slight_smile: )


#3

That makes sense. I ordered one with headers already soldered on and it came printing side down…

I can make a flipped version headers on the opposite side. At least it provides a little more info than standard pin designations.

Regarding DAC I also wouldn’t feed in 5v, into a 3.3 v, but we all make accidents :). I suppose as digital pins they are 5v tolerant, except for the listed ones…? I just want to clarify.

This bring me back, any ideas on the discrepancies of the pins between the two documents/links?

Different pins on each page

[quote]On Cerb-family boards, all pins are 5V tolerant except the 2 DAC pins, (PA.4, PA.6) and the reset pin.
[/quote]


#4

bump.

No I don’t know why PA5 and PA6 seemed to be mentioned in the docs as both being DAC2, although it looks like it might have been “cleaned up” by doco guru Jeff… seems like it’s PA5 only mentioned now !


#5

Hey Brett,

I don’t see the changes you speak of in the document links I’ve posted. There’s still conflicting Pins for non-5V tolerance.


#6

The schematic (found in the Product Catalog entry for Cerberus, under the Resorces tab) indicates it’s PA4, PA5. My reading of the datasheet seems to confirm that


#7

Right, yeah sorry about the confusion.

To summarise what we see…

The Cerberus general page lists the DAC pins as PA4 and PA6. The Cerb40 page says PA4 and PA5. which is correct?


#8

Thanks for clarifying that Brett.

I was just typing the same thing.


#9

well, it looks like the page was udpated:

https://www.ghielectronics.com/docs/46/cerb-family


#10

@ Jeff -

One more thing, on the [em]Fez Cerb 40 Developer Page[/em], it does not list PA5 Analog Channel Mapping, but the [em]Cerb Family[/em] it does have PA5 mapped to Analog 8 in the table.

Is this correct? does the Cerb 40 page need to be updated?

Thanks