Hydra and pulldown

Archive
1

I’ve just read the how-to to upgrade the firmware on the Hydra and a question comes in mind : GUS says that we should put MISO to GND in order to begin the process. Not more than 5 sec. Fine.

But… it also means that we won’t be able to use (at least) PA25 pin with a pulldown resistor in usual programs ? ???

Right now it’s not a problem because ResistorMode.Pulldown is throwing an exception at runtime, but I think it also implies that Pulldown may not be available at all for all other pins as well, which is somehow embarassing, I think.

Am I wrong ?

2

You are mixing things. Connecting miso to ground will block the processor from reading flash memory and so it ends up running atmel samba software which will give you a new virtual com port.

3

Sorry if I look like silly, but unless I miss something your answer seems to indicate that I can’t use the pin PA25 (on connector 3 or 4, see below) as a digital IO with a pulldown resistor.
In this case, as I understand it, the board won’t load the application but a bootloader. Because MISO has been pulled to ground.

Btw, is there only one SPI ? I ask that because connectors 3 & 4 are sharing the same MISO/MOSI pins on the schematics. Nothing wrong here, only curiosity :wink:

4

You are adding the wire ONLY and only for 5 seconds to update the firmware and this is ONLY done now since we do not have an adapter application.

So, why do you think you can’t use those pins? :slight_smile:

To be more clear, this is a temporary thing for “beta testers”. We are still making all kind of cool things for it, including a firmware update application. In which this is open source so feel free to contribute if you are interested.

5

Why didn’t you say that before ? :smiley:

I thought it was a permanent way of doing updates (though not really user-friendly).

Btw, it worked, so I won’t complain that much…

Now I don’t think this anymore… :-[

Thank you !

6

Glad it is clear now :slight_smile: Enjoy your FEZ Hydra :wink:

7

Can’t we use internal pulldown resistors on Hydra? It thows an exception. I tried sockets 3,4,7,9.
Edit: 4.1 project

8

This processor does not have pull down.

9

hmm, thanks a lot.