LPC47B37X View Datasheet(PDF) - SMSC -> Microchip
Part Name
Description
MFG CO.
LPC47B37X
SMSC -> Microchip
'LPC47B37X' PDF : 254 Pages View PDF
Software and hardware resets have the following effect on the PERPENDICULAR MODE COMMAND:
1. "Software" resets (via the DOR or DSR registers) will only clear GAP and WGATE bits to "0". D0-D3
are unaffected and retain their previous value.
2. "Hardware" resets will clear all bits
(GAP, WGATE and D0-D3) to "0", i.e all conventional mode.
WGATE
0
0
1
1
Table 27 - Effects of WGATE and GAP Bits
PORTION OF
GAP 2
LENGTH OF WRITTEN BY
GAP2 FORMAT WRITE DATA
GAP
MODE
FIELD
OPERATION
0 Conventional
22 Bytes
0 Bytes
1 Perpendicular
22 Bytes
19 Bytes
(500 Kbps)
0 Reserved
22 Bytes
0 Bytes
(Conventional)
1 Perpendicular
41 Bytes
38 Bytes
(1 Mbps)
LOCK
In order to protect systems with long DMA latencies against older application software that can disable the
FIFO the LOCK Command has been added. This command should only be used by the FDC routines,
and application software should refrain from using it. If an application calls for the FIFO to be disabled
then the CONFIGURE command should be used.
The LOCK command defines whether the EFIFO, FIFOTHR, and PRETRK parameters of the
CONFIGURE command can be RESET by the DOR and DSR registers. When the LOCK bit is set to logic
"1" all subsequent "software RESETS by the DOR and DSR registers will not change the previously set
parameters to their default values. All "hardware" RESET from the nPCI_RESET pin will set the LOCK bit
to logic "0" and return the EFIFO, FIFOTHR, and PRETRK to their default values. A status byte is
returned immediately after issuing a LOCK command. This byte reflects the value of the LOCK bit set by
the command byte.
Enhanced DUMPREG
The DUMPREG command is designed to support system run-time diagnostics and application software
development and debug. To accommodate the LOCK command and the enhanced PERPENDICULAR
MODE command the eighth byte of the DUMPREG command has been modified to contain the additional
data from these two commands.
69
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