I really don't know why ANYONE would want that Disk-on-a-Chip/Disk-on-a- piece-of-corn-on-the-cob stuff.
CompactFlash in TrueIDE mode works like a charm, it comes in many sizes, it's "second sourced" given there are many companies making CF cards, the specs are available for free, it's easily transportable, readable by laptops, desktops, etc, etc.
I had a friend at a company who was trying to evaluate the Disk-on-Chip stuff and the company basically ignored him since his quantities were less than 1K/year.
Anyway, I think as others have suggested, CF is the way to go!
A few years ago, I found some IDE flash ram drives that were the size of an 40pin header connector (IDE). To install then you just pushed them in the ide slot directly, and it was ready to go.
Anyone know of a source of these today? I was never able to purchase them, and the 2.5 & 3.5 FF drives are to big. I don't need one bigger than
Disk on Module from the same folks that bring you Disk On Chip. A flash based disk emulation with a built in IDE connector. I have seen several recently, and believe they still sell them.
Jay, Sounds like you've used a CF in true IDE mode?? I am in the midst of doing so in an embedded project , but am running into walls. Do you by chance have an exmaple code I can look at? Thanks.
I have to dig around and seee if I have any schematics left from the project.
If you get the CF spec
formatting link
(which I am sure you have) it tells you what happens to each pin in each of the modes. Typically, for TrueIDE, if memory serves, you have to more or less pull down pin #
You do have to follow the spec and pull-up and/or pull-down some of the other lines too, but they're not the "critical" ones.
Send me an e-mail with your address and I'll see what I can do.
Will do! Many people here have helped me out, this is the least I could do.
Note 1:
I made this table when I was trying to get the CF card to work in TrueIDE over the PCMCIA port. All the information still applies, but note that the "functionality" that pin 39 provides on the CF card isn't found on the PCMCIA port (i.e. CF pin 39 doesn't mate to any pin on the PCMCIA port even with a CF to PCMCIA adaptor).
To solve my problem (after making this table), I got a CF to PCMCIA converter and opened it up and hacked it, so I could get direct access to signals(like pin 39) and lift pins when needed. This hacked adaptor DID work reliably in my application, the host treated the CF card as a TrueIDE device (over the PCMCIA bus!).
Note 2: Signal direction is from the perspective of the CF card
Note 3: Many of the pins listed in this table were suggested to be disocnnected from the host by the CF spec(when the card is in TrueIDE mode). The host MAY pull-up or pull-down some lines, which might mess up the card, even if you have the right polarity. Be careful of this, that's why I suggest you disconnect them all if you can.
Note 4: CF spec says pull-ups should be >=10 kohms and pull-downs should be >= 100k ohms. I suspect this is for power reasons, but be aware...
Here we go:
CFPIN PCMCIA_PIN Direction Pull-Up/Down Name
8 8 I Pull-down A10
9 9 I Pull-down -ATASEL
10 11 I Pull-down A09
11 12 I Pull-down A08
12 22 I Pull-down A07
14 23 I Pull-down A06
15 24 I Pull-down A05
16 25 I Pull-down A04
17 26 I Pull-down A03
36 15 I Pull-up -WE
39 (None) None Pull-down -CSEL
43 60 O (Nothing) -INPACK
44 61 I Pull-up -REG
Important signal description:
Pin 9(-ATASEL):
This is really "the" signal that tells our CF card to goto TrueIDE mode.
Pin 39(-CSEL):
This tells the CF card, in TrueIDE if it's Master or Slave on the IDE channel. This signal is internally pulled high(Slave), but to make the card the Master on the IDE bus, pin 39 needs to be pulled-low(Master).
Since I did not have the schematics to the PCMCIA host I was working with, I did not know if they pulled certain signals high or low (i.e. violated the PCMCIA spec). For this reason, I suggest, at least for debugging, you disconnect all the above pins (from the host to the CF card) and make sure the above CF pins are tied high or low through a resistor to be safe.
Also, if this applies, make sure that your PCMCIA Card Detect pins (1,34,35,58) are grounded. When messing with my adaptor, I missed one and my host wouldn't recognize my card until I fixed that.
I have a PDF, which I created from reading books, specs, that actually makes a mapping between IDE and PCMCIA with pin names, etc. I'll consider sending it out. (I have a PDF of the above table too, but I don't think people here take kindly to binaries). For what it's worth, I've also hooked an IDE HDD to the same PCMCIA host that used my CF card in TrueIDE mode!
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