
SMSC DS – LPC47M192 
Page 42 
Rev. 03/30/05 
DATASHEET 
BIT NO.
4 
SYMBOL
OR 
NAME
DESCRIPTION
Overrun/  
Underrun 
Becomes set if the FDC does not receive CPU or DMA 
service within the required time interval, resulting in data 
overrun or underrun. 
Unused.  This bit is always "0". 
Any one of the following: 
1.  Read Data, Read Deleted Data command - the FDC 
did not find the specified sector. 
2.  Read ID command - the FDC cannot read the ID field 
without an error. 
3.  Read A Track command - the FDC cannot find the 
proper sector sequence. 
Not Writeable WP pin became a "1" while the FDC is executing a Write 
Data, Write Deleted Data, or Format A Track command. 
Missing 
Address Mark 
1. The FDC did not detect an ID address mark at the 
specified track after encountering the index pulse 
from the nINDEX pin twice. 
2.   The FDC cannot detect a data address mark or a 
deleted data address mark on the specified track. 
3 
2 
ND 
No Data 
1 
NW 
0 
MA 
Any one of the following: 
Table 14  – Status Register 2 
BIT NO.
7 
6 
SYMBOL
NAME
DESCRIPTION
CM 
Control Mark 
Unused.  This bit is always "0". 
Any one of the following: 
Read Data command - the FDC encountered a deleted 
data address mark. 
Read Deleted Data command - the FDC encountered a 
data address mark. 
The FDC detected a CRC error in the data field. 
5 
DD 
Data Error in 
Data Field 
Wrong 
Cylinder 
Bad Cylinder 
4 
WC 
The track address from the sector ID field is different 
from the track address maintained inside the FDC. 
Unused.  This bit is always "0". 
Unused.  This bit is always "0". 
The track address from the sector ID field is different 
from the track address maintained inside the FDC and is 
equal to FF hex, which indicates a bad track with a hard 
error according to the IBM soft-sectored format. 
The FDC cannot detect a data address mark or a 
deleted data address mark. 
3 
2 
1 
BC 
0 
MD 
Missing Data 
Address Mark 
Table 15  – Status Register 3 
BIT NO.
7 
6 
SYMBOL
NAME
DESCRIPTION
WP 
Write 
Protected 
Track 0 
Head Address Indicates the status of the HDSEL pin. 
Drive Select 
Indicates the status of the DS1, DS0 pins. 
Unused.  This bit is always "0". 
Indicates the status of the WRTPRT pin. 
5 
4 
3 
2 
1,0 
T0 
HD 
DS1,0 
Unused.  This bit is always "1". 
Indicates the status of the TRK0 pin. 
Unused.  This bit is always "1".