Dear all,

Can anyone point me to details on using CF cards? I haven't found much 
so far...

I'd like to use some kind of large (32MB or more) nv memory in my 
embedded system. Is CF a good choice? If not then what is?

Wlad

On Fri, 19 Dec 2003 19:04:17 +0100, Wlad <w...@wp.pl> wrote:

>Dear all,
>
>Can anyone point me to details on using CF cards? I haven't found much 
>so far...
>
>I'd like to use some kind of large (32MB or more) nv memory in my 
>embedded system. Is CF a good choice? If not then what is?

It may or may not be.  What does your system want to do? 

The main limitation for CF is that it is flash -- you can't write
flash over and over again without it failing eventually.

As for using them, there are multiple ways to access CF.  Hit
CompactFlash.org and you can download the specs.
-- 
Alex Pavloff - remove BLAH to email
Software Engineer, ESA Technology

Wlad <w...@wp.pl> wrote in message news:<3...@wp.pl>...
> Dear all,
> 
> Can anyone point me to details on using CF cards? I haven't found much 
> so far...

In true ATA mode, same as using an IDE hard disk.
In memory mode, same as using paged memory.

> 
> I'd like to use some kind of large (32MB or more) nv memory in my 
> embedded system. Is CF a good choice? If not then what is?

If your system can handle IDE drives, then CF is the best choice.

> 
> Wlad

IDE Compact Flash Drive at http://ide-cf.info-for.us

Tech Support for IDE-CF wrote:

> IDE Compact Flash Drive at http://ide-cf.info-for.us

What a weird website.

> I'd like to use some kind of large (32MB or more) nv memory in my 
> embedded system. Is CF a good choice? If not then what is?

Depends.  If you expect to

 - want more memory, or
 - produce small quantities, or
 - have your product still produced in a few years

then CF certainly is a wise choice.

Otherwise you may jump on the cellular phone waggon and choose
whatever chip they currently use. Today, most have 4-8 MB ('320/640).
Sharps LRS1395A for example is a dual-die MCP (16MB total).  Using
two of them is certainly cheaper than a CF + socket.  But be careful,
once the cellur phone industry doesn't want this chip anymore, it
will probably disappear in no time.

Marc

Wlad wrote:
> Dear all,
> 
> Can anyone point me to details on using CF cards? I haven't found much 
> so far...
> 
> I'd like to use some kind of large (32MB or more) nv memory in my 
> embedded system. Is CF a good choice? If not then what is?
> 
> Wlad
> 

Depends on your embedded system -- For example if your using a Motorola 
Processor you may consider MMC or SD Flash memory as both support the 
serial SPI interface -- an interface found in many Motorola Processors.

JoeG <J...@yahoo.com> writes:

>> I'd like to use some kind of large (32MB or more) nv memory in my 
>> embedded system. Is CF a good choice? If not then what is?

>Depends on your embedded system -- For example if your using a Motorola 
>Processor you may consider MMC or SD Flash memory as both support the 
>serial SPI interface -- an interface found in many Motorola Processors.

Using SPI is definitely a bad choice when you are  thinking  of  mass
data  transfers.  On  some devices (like MPC8xx) the SPI interface is
awfully slow. Even Motorola says: "SPI was not designed to be a high-
bandwidth channel." (see FAQ-10335).

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88   Web: www.denx.de
How does a project get to be a year late?      ... One day at a time.

"Wolfgang Denk" <w...@denx.muc.de> schrieb im Newsbeitrag
news:H...@denx.muc.de...
> JoeG <J...@yahoo.com> writes:
>
> >> I'd like to use some kind of large (32MB or more) nv memory in my
> >> embedded system. Is CF a good choice? If not then what is?
>
> >Depends on your embedded system -- For example if your using a Motorola
> >Processor you may consider MMC or SD Flash memory as both support the
> >serial SPI interface -- an interface found in many Motorola Processors.
>
> Using SPI is definitely a bad choice when you are  thinking  of  mass
> data  transfers.  On  some devices (like MPC8xx) the SPI interface is
> awfully slow. Even Motorola says: "SPI was not designed to be a high-
> bandwidth channel." (see FAQ-10335).

That's why SPI-4.2 is only used with 622 to 800 megabits per second...
(bundled up to 10Gbits)
See Xilinx app notes.

MIKE

M.Randelzhofer wrote:
> "Wolfgang Denk" <w...@denx.muc.de> schrieb im Newsbeitrag
> news:H...@denx.muc.de...
> 
>>JoeG <J...@yahoo.com> writes:
>>
>>
>>>>I'd like to use some kind of large (32MB or more) nv memory in my
>>>>embedded system. Is CF a good choice? If not then what is?
>>
>>>Depends on your embedded system -- For example if your using a Motorola
>>>Processor you may consider MMC or SD Flash memory as both support the
>>>serial SPI interface -- an interface found in many Motorola Processors.
>>
>>Using SPI is definitely a bad choice when you are  thinking  of  mass
>>data  transfers.  On  some devices (like MPC8xx) the SPI interface is
>>awfully slow. Even Motorola says: "SPI was not designed to be a high-
>>bandwidth channel." (see FAQ-10335).
> 
> 
> That's why SPI-4.2 is only used with 622 to 800 megabits per second...
> (bundled up to 10Gbits)
> See Xilinx app notes.
> 
> MIKE
> 
> 
> 
> 


A couple of things -- again it depends on the application -- if the 
Memory is only going to be used for configuration with some minor 
read/writes -- SPI is fine. After all, MMC and SD have SPI.

If you have high bandwidth needs than a parallel approach is the ticket 
such as with CF (ATA/IDE)...

In article <jaQFb.1140$2...@newssvr27.news.prodigy.com>, JoeG wrote:
> If you have high bandwidth needs than a parallel approach is the ticket 
> such as with CF (ATA/IDE)...

The CF is faster, but the memory cycles are slow when compared to modern
microcontrollers.  You may need lots of wait cycles (20 or 100 even), which
slows down your MCU.  Interfacing CF to an MCU with no built-in CF support
may require some glue logic (for timing, address decodign and control signal
generation).  Also, many CF cards are slow writing data (100...200
kilobytes/s).  But I still use CF cards.. ;-)

  -jm