LPC47N227TQFP Standard Microsystems (SMSC), LPC47N227TQFP Datasheet - Page 38

• Manufacturer Part Number: LPC47N227TQFP
• Manufacturer: Standard Microsystems (SMSC)

Specifications of LPC47N227TQFP

• Lead Free Status / RoHS Status: Not Compliant

required.
Data Transfer Termination
The FDC supports terminal count explicitly through the TC cycle and implicitly through the
underrun/overrun and end-of-track (EOT) functions. For full sector transfers, the EOT parameter can
define the last sector to be transferred in a single or multi-sector transfer.
If the last sector to be transferred is a partial sector, the host can stop transferring the data in mid-sector,
and the FDC will continue to complete the sector as if a TC cycle was received. The only difference
between these implicit functions and TC cycle is that they return "abnormal termination" result status.
Such status indications can be ignored if they were expected.
Note that when the host is sending data to the FIFO of the FDC, the internal sector count will be complete
when the FDC reads the last byte from its side of the FIFO. There may be a delay in the removal of the
transfer request signal of up to the time taken for the FDC to read the last 16 bytes from the FIFO. The
host must tolerate this delay.
Result Phase
The generation of the interrupt determines the beginning of the result phase. For each of the commands,
a defined set of result bytes has to be read from the FDC before the result phase is complete. These
bytes of data must be read out for another command to start.
RQM and DIO must both equal "1" before the result bytes may be read. After all the result bytes have
been read, the RQM and DIO bits switch to "1" and "0" respectively, and the CB bit is cleared, indicating
that the FDC is ready to accept the next command.
Command Set/Descriptions
Commands can be written whenever the FDC is in the command phase. Each command has a unique
set of needed parameters and status results. The FDC checks to see that the first byte is a valid
command and, if valid, proceeds with
sends a Sense Interrupt Status command which returns an invalid command error. Refer to Table 16
for explanations of the various symbols used. Table 17 lists the required parameters and the results
associated with each command that the FDC is capable of performing.
C
D
D0, D1
DIR
DS0, DS1
SYMBOL
Cylinder Address
Data Pattern
Drive Select 0-1
Direction Control
Disk Drive Select
NAME
Table 16 – Description of Command Symbols
The currently selected address; 0 to 255.
The pattern to be written in each sector data field during formatting.
Designates
Perpendicular Mode Command.
drive.
If this bit is 0, then the head will step out from the spindle during a
relative seek. If set to a 1, the head will step in toward the spindle.
the command. If it is invalid, an interrupt is issued. The user
DS1
0
0
which
38
DS0
0
1
drives
Drive 0
Drive 1
DESCRIPTION
DRIVE
are
A "1" indicates a perpendicular
perpendicular
drives
on
the