SD Card installation

[nickxab]

is it possible to add a sd card slot on the stock motherboard ?

[MikeB]

Not really.
First, the SD card has a 3.3V interface, the MEGA64 is running at 5V.
Second, we don't have the spare I/O pins to connect with.
Third, we don't have much much space flash memory for the code to use the SD card.
Fourth, We don't have much spare RAM to store data as it is read or needs to be written.

Those are my immediate thoughts!

Mike.

[jhsa]

maybe another mega or tiny could handle the card and the telemetry data could pass through? of course I have no idea of what I'm saying, so if it is really bad just tell me to shut up

[Clivew]

Ignore him, he's Fortuguese

[jhsa]

ha, another one that doesn't know what a "Plap" is..

[MikeB]

maybe another mega or tiny could handle the card and the telemetry data could pass through?

It might be possible, but the time taken to design and implement would be significant. Since we have the ersky9x board available, I think it would be easier, and probably not much more costly, to just put one of them in. If starting with a new 9x, and getting the SP board, serial converter AND an addon Sd card board you would probably spend almost as much, if not more than the ersky9x board.

Mike.

[jhsa]

Well, I and many others have already a couple of 9X's with all the available mods done.. I think would be much more expensive to fit a sky board on them now

Plus we'd be throwing away all the time and sweat we've put in it.. Hacking spirit.. I think this radio still has a lot more to give.. thanks to people like yourself..
and it's not only the money, it's the spirit. look where we got to..
At the moment the only thing the modded stock board can't do that the sky board can is reading SD Card I think the only difference is that the stock is slower and doesn't have as much flash.. eeprom could probably be shared with the other CPU..
we still got space for one more board inside the case

HHmmm, another good subject to nag about

Long Life To The 9x. 9x Forever

João ( The Nagging Fortuguese)

[nickxab]

Oh i see....hehe thanks for your replies guys !!!

[tilmanb]

I found this on radioclone.org
http://radioclone.org/en/hardware/self

He uses the same pins as for the ISP programmer. Which makes sense since it's SPI. I don't like his zener diode level shifter setup very much, but that could be fixed easily with a proper level shifter chip. Although 3.3V HIGH is still pretty safely within TTL HIGH range. So what the heck, it will probably just work.

Any reason this could not be done with open9x on he stock board?

[MikeB]

You need the SCK signal as well as the two data lines, so it is not just as simple as using the programming signals, which are used for switch inputs normally, unless you do the FrSky mod when they are used for the serial data from the tx module.

Mike.

[Kilrah]

Just a little correction, it's not the same pins as for the ISP (apart from SCK), but the "real" SPI port.

It looks like they manage to "share" the SPI pins with the EXIT/DOWN keys without too much trouble, but have to keep the speed low probably due to the capacitors to ground.
That would likely prevent doing anything "interesting" with it. In Radioclone's case it makes some sense as the internal eeprom can otherwise only store a single model. So the SD is only used when nothing else is being done, and timing is not critical.

[tilmanb]

H, I thought it might not be quite so easy. Thanks for elaborating.

Just out of interest. What available pins does the stock board CPU have and how are they being used already?
Is there a list somewhere perhaps?

[Kilrah]

viewtopic.php?f=5&t=2732&p=38298#p38298

[jhsa]

the radio very soon might be able to use the Voice Module's SD Card to store data.. Of course you'll have to get yourself a MegaSound9X module. You can build it, or buy it

João

[MikeB]

I've got so much going on I haven't managed to do much on that yet, but it is on my todo list.

Mike.

[tilmanb]

Three pins in total. Hm, perhaps we could do some i2c with that and add a IO expander chip?
Or use that as a sort of three bit address bus for the display 'bus'.

Damn, I need to stop getting ahead of myself. Need to find the full schematics and AVR PIN definitions...

[Kilrah]

That's pretty much what the sound module does. A second processor that offloads the SD and playback stuff, and communicates with the main one.

[jhsa]

and with a computer..

[tilmanb]

I'm actually looking into that stuff right now. Have not fully grokked it yet. But those AVR based sound modules look really sweet as a IO expander/co-processor.
If someone could perhaps explain to me the interface in plain English?