CF DMA support

[dalai lamah]

I'm running XPE on a Compactflash connected to the IDE bus of a PC104
motherboard; the motherboard is equipped with the Intel 815 chipset, and
the XPE driver for the IDE controller (detected by TAP) is the "82801BA
Ultra ATA Controller".

I've tried with several CompactFlash models, but I haven't been able to
enable the DMA mode for any of them; I'm always stuck with PIO mode and a
sad transfer rate of 2 or 3 MB/s. The models I've tried are (supposedly)
known to support DMA mode (Sandisk Extreme III, several Transcend, and
others), and I'm having the same problem also with a normal hard disk, so
I'm starting to believe it could be a driver problem. If I try to install
the Intel Ultra Ata Storage Driver, the system is no longer able to boot,
it freezer forever on the Windows XP splash screen.

Do you have any suggestions? Diagnostics to run, registry keys to check,
drivers to install...

Thank you!

 

[Stuart Langley]

Silly question, but does you hardware support DMA or not (regardless of the
software)? DMA requires certain track lengths etc to work properly, and
should not be assumed to be supported on all devices.

 

[Sean Liming \(eMVP\)]

I have been told that the CF to IDE needs to have the pin out enabled for
DMA.

Regards,

Sean Liming
www.sjjmicro.com / www.seanliming.com
XP Embedded Book Author - XP Embedded Advanced, XP Embedded Supplemental
Toolkit

 

[dalai lamah]

Un bel giorno Stuart Langley digitò:

Silly question, but does you hardware support DMA or not (regardless of the
software)? DMA requires certain track lengths etc to work properly, and
should not be assumed to be supported on all devices.

The hardware should be ok; the motherboard supports DMA (at least the
specifications say so), and the CompactFlash is mounted on a simple adapter
(a PC104 board that does nothing else to route the CF signals to a strip)
and the flat cable that connects the two boards is long 4 or 5 cm.

I've already contacted the MB manufacturer for this kind of issues, but
still no useful answers from them...

 

[dalai lamah]

Un bel giorno Sean Liming (eMVP) digitò:

I have been told that the CF to IDE needs to have the pin out enabled for
DMA.

This is very interesting, do you have any further informations? Thank you!

 

[alishaukat2002]

Dear lamah ;

Does your compact Flash Adapter suppport DMA mode ?
its also depend on adapter .

Regards

 

[KM]

Just wondering how exactly do you set DMA mode for the card?

Basically you can turn on the DMA mode or set to PIO only in Device Manager, "IDE ATA/ATAPI Controllers" node, channel your CF is
on, Advanced Settings tab, Transfer Mode combo for Device 0/1. Is this how

And could you post here the content of the
[HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E96A-E325-11CE-BFC1-08002­BE10318}\0000],"TransferModeTiming" registry value on
your runtime?
If it always gets back to PIO only value your problem is probably about the driver or the OS. If not, it may be the hardware issue -
CF doesn't support DMA or adapter problems or etc.

 

[dalai lamah]

Un bel giorno Sean Liming (eMVP) digitò:

I have been told that the CF to IDE needs to have the pin out enabled for
DMA.

That was it! DMARQ and DMACK were left floating, I've connected them to the
appropriate CF pins, re-run the boot agent, and now DMA mode works
perfectly.

Thank you again!