LPC47N227-MN Ver la hoja de datos (PDF) - SMSC -> Microchip
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LPC47N227-MN Datasheet PDF : 202 Pages
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Normal mode. Register 3F3 contains only bits 0 and 1. When this register is read, bits 2 - 7 are ‘0’.
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
REG 3F3
0
0
0
0
0
0
tape sel1 tape sel0
Enhanced Floppy Mode 2 (OS2)
Register 3F3 for Enhanced Floppy Mode 2 operation.
DB7
DB6
REG 3F3 Reserved Reserved
DB5
DB4
Drive Type ID
DB3
DB2
DB1
DB0
Floppy Boot Drive tape sel1 tape sel0
Table 6 – Drive Type ID
DIGITAL OUTPUT REGISTER
REGISTER 3F3 - DRIVE TYPE ID
Bit 1
Bit 0
Bit 5
Bit 4
0
0
CR06 - B1
CR06 - B0
0
1
CR06 - B3
CR06 - B2
1
0
CR06 - B5
CR06 - B4
1
1
CR06 - B7
CR06 - B6
Note: CR06-Bx = Configuration Register 06, Bit x.
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.
7
6
5
4
3
2
1
0
S/W POWER 0
PRE- PRE- PRE- DRATE DRATE
RESET DOWN
COMP2 COMP1 COMP0 SEL1 SEL0
RESET 0
0
0
0
0
0
1
0
COND.
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.
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