LPC47N227TQFP Standard Microsystems (SMSC), LPC47N227TQFP Datasheet - Page 27

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

Specifications of LPC47N227TQFP

• Lead Free Status / RoHS Status: Not Compliant

Enhanced Floppy Mode 2 (OS2)
Register 3F3 for Enhanced Floppy Mode 2 operation.
Note:
Data Rate Select Register (DSR)
Address 3F4 WRITE ONLY
This register is write only. It is used to program the data rate, amount of write precompensation, power
down status, and software reset. The data rate is programmed using the Configuration Control Register
(CCR) not the DSR, for PC/AT and PS/2 Model 30 applications. Other applications can set the data rate
in the DSR. The data rate of the floppy controller is the most recent write of either the DSR or CCR. The
DSR is unaffected by a software reset. A hardware reset will set the DSR to 02H, which corresponds to
the default precompensation setting and 250 Kbps.
BIT 0 and 1 DATA RATE SELECT
These bits control the data rate of the floppy controller. See Table 8 for the settings corresponding to the
individual data rates. The data rate select bits are unaffected by a software reset, and are set to 250 Kbps
after a hardware reset.
BIT 2 through 4 PRECOMPENSATION SELECT
These three bits select the value of write precompensation that will be applied to the WDATA output
signal. Table 7 shows the precompensation values for the combination of these bits settings. Track 0 is
the default starting track number to start precompensation. This starting track number can be changed by
the configure command.
REG 3F3
REG 3F3 Reserved Reserved
RESET
COND.
CR06-Bx = Configuration Register 06, Bit x.
DIGITAL OUTPUT REGISTER
DB7
DB7
0
Bit 1
RESET
0
0
1
1
S/W
7
0
DB6
DB6
POWER
0
DOWN
6
0
Bit 0
0
1
0
1
DB5
DB5
Drive Type ID
Table 6 – Drive Type ID
0
5
0
0
COMP2
PRE-
DB4
DB4
27
0
4
0
REGISTER 3F3 - DRIVE TYPE ID
CR06 - B1
CR06 - B3
CR06 - B5
CR06 - B7
Bit 5
COMP1
PRE-
Floppy Boot Drive
DB3
DB3
3
0
0
COMP0
PRE-
DB2
DB2
2
0
0
CR06 - B0
CR06 - B2
CR06 - B4
CR06 - B6
Bit 4
DRATE
SEL1
tape sel1
tape sel1
1
1
DB1
DB1
DRATE
SEL0
0
0
tape sel0
tape sel0
DB0
DB0