SparkFun Forums

[JimmyM]

The schematic linked here http://cdn.sparkfun.com/datasheets/Dev/ ... o_v13a.pdf is wrong on a couple of pins.

It shows...
PB0(SS) on pin 11 (labelled MISO) --- pin 11 is actually PB3(MISO)
PB3(MISO) on pin 8 (labelled D14) --- pin 8 is actually PB0(SS)

[darrellg]

Did you read the changelog in the top right corner?

[Ross Robotics]

And you didn't have to make 2 posts regarding "incorrect" assumptions on the same product.

[JimmyM]

I still don't see in the changelog in the upper right of the schematic why pins 8 and 11 are swapped in the labelling on the chip versus the arduino pin assignments. I see the changes regarding pins 14 & 17.

Sorry. What was my other post with an incorrect assumption about the Pro Micro? I know I asked a question regarding the ADC count. But that's it.

[Ross Robotics]

I still don't see in the changelog in the upper right of the schematic why pins 8 and 11 are swapped in the labelling on the chip versus the arduino pin assignments. I see the changes regarding pins 14 & 17.

Attached is an image of the PDF schematic linked on the product page.

Sorry. What was my other post with an incorrect assumption about the Pro Micro? I know I asked a question regarding the ADC count. But that's it.

The same schematic will explain why. A0-A3 are the only ones available. I haven't read the datasheet thoroughly but, looks like there are some limitations when use multiple ADC channels.

[JimmyM]

OK. I'm not going to argue, but when the chip symbol says SS and the pin is labelled MISO and vice versa, it is confusing.

I'll read the datasheet regarding ADCs and do some testing.

[uChip]

That does seem weird. On the ATmega datasheet (version 7766-H) pin 8 is SS and pin 11 is MISO. Looks like somebody swizzled the pin numbers but forgot to swizzle the names.

I see on github that a change was made to "Fixing 32U4 pin names" a little over two weeks ago. The schematic there matches the product page (pin 8 = MISO). That conflicts with the Atmel datasheet.

You should maybe contact SparkFun tech support, but there's no substitute for ohming out the board.

Good luck,
- Chip

NOTE: When you post in the forums and you get answers, those answers are usually from other people like yourself, NOT SparkFun employees. You can tell when a SparkFunner responds because their names are in red.

[JimmyM]

Exactly. Thank you.

[uChip]

I have taken the liberty of creating an issue for the pin swap on the Pro Micro github repository. From what research I did, the traces on the board seem to be correct. It is the naming of the pins inside the ATMEGA32U4 component that are swapped/wrong. I compared the rest of the pin names against the Atmel data sheet. All but those two appear to match. That component is from a library named "Testing" so perhaps the error has something to do with that. I cross checked the 32U4 component in the SparkFun library on github and that library component has all pins named the same as the datasheet.

- Chip

[JimmyM]

Much appreciated, Chip.