actually Im trying to figure out how rokicki knew what resistor to put in on his circuit in the picture. I have the breakout board from spark fun electronic and not have much luck in finding example of interfacing. found 2 examples from winbond, both are different in connection and resistor used.
The pullup resistors I got from the spec (I believe it says something like 10K -> 100K or some such).
The current limiters are not necessary, and only there to protect things in case software goes wrong
and both the propeller and the SD chip decide to drive a pin at the same time; I picked the value I
did based on the expected operating frequency, the current limits of the propeller pins, and the
expected capacitance of the inputs.
rokicki said...
The pullup resistors I got from the spec (I believe it says something like 10K -> 100K or some such).
The current limiters are not necessary, and only there to protect things in case software goes wrong
and both the propeller and the SD chip decide to drive a pin at the same time; I picked the value I
did based on the expected operating frequency, the current limits of the propeller pins, and the
expected capacitance of the inputs.
when you say 'spec', are you refering to parallax spec or sd spec?
If you are lazy like me, and don't mind paying 29 (42 for CF) instead of 14$ (Not trying to stray anyone away from Sparkfun, love them... But sometimes I like to take the shorter route).... This place has a complete solution for both CF and SD using a serial interface.. They also have both a 5v and 3v version of the SD reader/writer.. The SD version was taken off the site temporarily apparently because they are reworking the PCB, but if you request one they will sell it to you.
Heh, not at all. Some other folks pushed things further than I did (getting
assembly read routines in there; don't recall on the writing). It's certainly
something I may work on some more if there is demand; it's not hard.
I haven't been able to find enough time to really work on the propeller
like I want lately, though.
Anyone else got progress to report on SD/MMC read/write?
I got an assembly SD card reader working, with the code posted in another thread.
I can imagine an SD card writer could be a useful thing, especially a full FAT file writer, but it's just not high on my priorities at the moment to try to write one.
Bean has an SD Data Logger that would seem to interface easily with the Propeller and manage the file system.· If you look at a hard disk's internal operation, there is an analogy to doing it this way as it frees up the microprocessor to do more creative things.· While many of these devices only allow 4 files per card, his allows 16 files.· And it handles a wide voltage range with its own on-board regulator [noparse][[/noparse]3.6 to 7.5 VDC].· The interface is 19,200 or 2400 baud 8N1.
Has anyone tried this?
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
···················· Tropical regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
I've used Bean's SD Data Logger. It's fine as a data logger, but not as a general purpose SD access device. For example, you can't delete files or overwrite them and there's no subdirectory support. It's very limited in the amount of card space it can use (again, fine for a logger).
I got a molex connector and am ready to start a breakout board for it. Could I get a second opinion on the connections per the schematic in Rokicki's sdspi.spin object.
The Sandisk PDF document says that any input that may float should have a pullup. I've heard that some people have gotten away without doing so, but the document says that the card may experience high current draw if unused inputs are not pulled up.
In SPI mode, pin 1, CS, pin 2, data out (to card) and pin 5, clock, are always driven by the controller, and pin 7, data out from the card, is always driven by the card, so none of them need pullups because they never are left floating (with the card in its socket).
Pins 8 and 9 are recommended by the document to have pullups connected to protect the card, since these have no external controller connection in SPI mode.
In addition, Sandisk suggests that pullups might be helpful to protect the controller input for when the card is ejected from its socket, so if you want to do that, you could add a pullup to pin 7.
FYI - Your diagram doesn't show it but the card pins are numbered oddly. Pin 9 is the recessed pin at the diagram top. Next to pin 9 is pin 1, then pin 2, down to pin 8 on the bottom. That's because the original MMC card had only the 7 pins 1-7, and later on, the SD squeezed in the two additional pins 8 and 9 on the available space at each end but kept the original pins 1-7 for compatability.
I will also have the room for all pull-ups. It's Rokicki's object and specifies having them, so I will include them. I mainly wanted to verify DO and DI as they came from different sources. The picture on this page is great, but I can't see the traces to verify.
Comments
actually Im trying to figure out how rokicki knew what resistor to put in on his circuit in the picture. I have the breakout board from spark fun electronic and not have much luck in finding example of interfacing. found 2 examples from winbond, both are different in connection and resistor used.
The current limiters are not necessary, and only there to protect things in case software goes wrong
and both the propeller and the SD chip decide to drive a pin at the same time; I picked the value I
did based on the expected operating frequency, the current limits of the propeller pins, and the
expected capacitance of the inputs.
when you say 'spec', are you refering to parallax spec or sd spec?
http://www.comfiletech.com/index.asp?PageAction=VIEWPROD&ProdID=80&strVarSel=&strCompare=
How far have you got with the SD Write routine(s)?
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Cheers,
Simon
<hr />
www.norfolkhelicopterclub.co.uk
Post Edited (simonl) : 10/17/2006 4:52:44 PM GMT
assembly read routines in there; don't recall on the writing). It's certainly
something I may work on some more if there is demand; it's not hard.
I haven't been able to find enough time to really work on the propeller
like I want lately, though.
Anyone else got progress to report on SD/MMC read/write?
I can imagine an SD card writer could be a useful thing, especially a full FAT file writer, but it's just not high on my priorities at the moment to try to write one.
David
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Cheers,
Simon
www.norfolkhelicopterclub.co.uk
You'll always have as many take-offs as landings, the trick is to be sure you can take-off again ;-)
Post Edited (simonl) : 10/18/2006 1:02:38 PM GMT
Has anyone tried this?
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
In SPI mode, pin 1, CS, pin 2, data out (to card) and pin 5, clock, are always driven by the controller, and pin 7, data out from the card, is always driven by the card, so none of them need pullups because they never are left floating (with the card in its socket).
Pins 8 and 9 are recommended by the document to have pullups connected to protect the card, since these have no external controller connection in SPI mode.
In addition, Sandisk suggests that pullups might be helpful to protect the controller input for when the card is ejected from its socket, so if you want to do that, you could add a pullup to pin 7.
FYI - Your diagram doesn't show it but the card pins are numbered oddly. Pin 9 is the recessed pin at the diagram top. Next to pin 9 is pin 1, then pin 2, down to pin 8 on the bottom. That's because the original MMC card had only the 7 pins 1-7, and later on, the SD squeezed in the two additional pins 8 and 9 on the available space at each end but kept the original pins 1-7 for compatability.
David
http://www.rayslogic.com/propeller/Programming/SD_Card/SD_Card.htm
I'm going to try implementing file rename today...