Table 7 − Precompensation Delays
PRECOMP
432
PRECOMPENSATION
DELAY (nsec)
<2Mbps
0.00
2Mbps
0
111
001
010
011
100
101
110
000
41.67
20.8
41.7
62.5
83.3
104.2
125
83.34
125.00
166.67
208.33
250.00
Default
Default
Default: See Table 10
Table 8 − Data Rates
DATA RATE DATA RATE
DRIVE RATE
DENSEL
DRATE(1)
DRT1
DRT0
SEL1
SEL0
MFM
FM
1
0
0
0
0
0
0
0
0
0
1
0
0
1
1
0
1
0
1Meg
500
---
1
1
0
0
1
0
0
1
1
0
1
0
250
150
125
300
250
0
0
0
0
1
1
1
1
1
0
0
1
1
0
1
0
1Meg
500
---
1
1
0
0
1
0
0
1
1
0
1
0
250
250
125
500
250
1
1
1
1
0
0
0
0
1
0
0
1
1
0
1
0
1Meg
500
---
250
---
1
1
0
0
1
0
0
1
1
0
1
0
2Meg
250
125
Drive Rate Table (Recommended) 00 = 360K, 1.2M, 720K, 1.44M and 2.88M Vertical Format
01 = 3-Mode Drive
10 = 2 Meg Tape
Note 1: The DRATE and DENSEL values are mapped onto the DRVDEN pins.
Table 9 − DRVDEN Mapping0
DT1
DT0
DRVDEN1 (1)
DRVDEN0 (1)
DRIVE TYPE
4/2/1 MB 3.5"
2/1 MB 5.25" FDDS
0
0
DRATE0
DENSEL
2/1.6/1 MB 3.5" (3-MODE)
1
0
1
0
1
1
DRATE0
DRATE0
DRATE1
DRATE1
nDENSEL
DRATE0
PS/2
SMSC DS – LPC47S45x
Page 34 of 259
Rev. 07/09/2001
DATASHEET
SMSC [ SMSC CORPORATION ]
