This message is from the T13 list server.
I'm sorry, I meant to say the device Data register.
I appreciate your quick response. Do you have any comments on my email
after substituting "device Data register" in for "device Drive register"?
I agree with your comments completely.
Where I see the discrepancy is:
During the HPIOI2: Transfer_Data state, you should not be reading
any register except the device Data register. So why would you read
the device Status register?
All the other figures and similar protocol states (PIO Data-out, HPIOO1:
Transfer_Data state) seem to conflict with the HPIOI2:HPIOI2
transition's text description.
--Mike
Mark Overby wrote:
The DRQ bit is located in the status register. There is no drive
register. If you mean the device (old dev/head register), that would be
the wrong register as well.
In order to know that the DRQ block has been completed, you have to go
back, wait for BSY to drop at the device, and then continue transferring
data. (Assuming there is more data to transfer). Note - that BSY could
go high and drop again before your host can read the status register, so
the host loops through HPIOI2->HPIOI1->HPIOI2 very quickly and you won't
actually spend any time there.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of
Michael G. Farley
Sent: Tuesday, January 31, 2006 10:19 AM
To: [email protected]
Subject: [t13] ATA/ATAPI-6 HPIOI2:HPIOI2 Transition
This message is from the T13 list server.
To whom it may concern,
I work with Green Hills Software based in Santa Barbara, CA. I've been
studying the ATA/ATAPI-6 Standard, and I think I've found a discrepancy.
In the Transition from HPIOI2 to HPIOI2, shouldn't the first line
read, "When the host has read the device Drive register..."?
The standard instead reads, "When the host had read the device Status
register".
Transition HPIOI2:HPIOI2: When the host has read the device status
register and the DRQ data block transfer has not completed, then the
host shall make a transition to the HPIOI2: Transfer_Data state.
I noticed that the latest ATA/ATATPI-7 Standard reads the same as the
ATA/ATAPI-6 Standard.
When I looked into the Figure 25 and 26, they read "device Drive
register" and not "device Status register".
You are the only email address I could find in the Standard. If you are
not the person I should be contacting, please let me know who is.
--Mike Farley
