LPC47N227TQFP Standard Microsystems (SMSC), LPC47N227TQFP Datasheet - Page 155

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

Specifications of LPC47N227TQFP

• Lead Free Status / RoHS Status: Not Compliant

CR18 - CR1E registers are reserved. Reserved registers cannot be written and return 0 when read.
The default value of these registers after power up is 00H on VCC POR.
CR1F
CR1F can only be accessed in the configuration state and after the CSR has been initialized to 1FH.
CR1F indicates the floppy disk Drive Type for each of four floppy disk drives. The floppy disk Drive
Type is used to map the three FDC DENSEL, DRATE1 and DRATE0 outputs onto two Super I/O output
pins DRVDEN1 and DRVDEN0 (Table 79).
CR20
CR20 can only be accessed in the configuration state and after the CSR has been initialized to 20H.
CR20 is used to select the base address of the floppy disk controller (FDC). The FDC base address
can be set to 96 locations on 8 byte boundaries from 100H - 3F8H. To disable the FDC set ADR9 and
ADR8 to zero. Set CR20.[1:0] to 00b when writing the FDC Base Address.
FDC Address Decoding: address bits A[15:10] must be ‘000000’ to access the FDC registers. A[3:0]
are decoded as 0XXXb.
DT0
DRIVE TYPE
BIT NO.
0
0
1
1
0
1
2
3
4
5
6
7
DT1
0
1
0
1
DENSEL
DRATE1
nDENSEL
DRATE0
Type: R/W
BIT NAME
FDD0 DT1
FDD0 DT0
FDD1 DT1
FDD1 DT0
FDD2 DT1
FDD2 DT0
FDD3 DT1
FDD3 DT0
DRVDEN0
DRATE0
DRATE0
DRATE0
DRATE1
Table 79 – Drive Type Encoding
DRVDEN1
Drive Type Bit 1 for FDD 0.
Drive Type Bit 0 for FDD 0.
Drive Type Bit 1 for FDD 1.
Drive Type Bit 0 for FDD 1.
Drive Type Bit 1 for FDD 2.
Drive Type Bit 0 for FDD 2.
Drive Type Bit 1 for FDD 3.
Drive Type Bit 0 for FDD 3.
Table 78 – CR1F
Drive Type
155
4/2/1 MB 3.5”
2/1 MB 5.25” FDDS
2/1.6/1 MB 3.5” (3-MODE)
PS/2
DRIVE TYPE DESCRIPTION
DESCRIPTION
Default: 0x00 on VCC POR