
ISD-300A1
28
October 19, 2001
ATA/ATAPI Interface
The ATA/ATAPI port on the ISD-300A1 is compliant with the
Information Technology – AT Attachment
with Packet Interface – 5 (ATA/ATAPI-5) Specification, T13/1321D Rev 3
. The ISD-300A1 supports both
ATAPI packet commands as well as ATA commands (by use of ATA Command Blocks). Additionally,
the ISD-300A1 translates ATAPI SFF-8070i commands to ATA commands for seamless integration of
ATA devices with generic Mass Storage Class BOT drivers. The ISD-300A1 also provides a vendor-
specific “event notify” ATA command to automatically communicate certain USB and system events to the
attached device.
Protocol
The ISD-300A1 supports command protocol flows as defined in the
ATA/ATAPI-5 Specification
.
Commands are grouped into different classes, based on the protocol followed for command execution.
The ATA/ATAPI interface supports the following clarifications:
Immediately after the reset recovery period, the ISD-300A1 will write 0x00 to the Device Control
register.
Arbitrary byte count transfers are supported.
16-bit data reads and writes are supported.
8-bit data transfers are not supported.
Reset Mapping
The ATA/ATAPI interface responds to several resets: Power-on, USB, MSC, and Vendor-specific Soft
reset.
In the case of a power-on reset, a full device initialization is performed. FBh data is retrieved and stored if
the I_MODE pin is set active.
In the cases of USB reset and MSC reset, a partial initialization is performed which excludes all attempts to
perform Identify Device commands.
In the case of a Vendor-specific Soft reset, only the internal ISD-300A1 state machines are reset.
Device Requirements
Attached mass storage devices must support the following:
ATA Reset, A1h, FBh
After deassertion of ATA_NRESET, BSY and DRQ must be cleared by the device within the ATA
Initialization Timeout configuration setting value.
ATA Polling Device
The device shall be capable of being a polling only device. The ATA signal
INTRQ
is not used by the
ISD-300A1.