PC87373 datasheet(140/174 Pages) NSC

140 / 174 page

140

www.national.com

Revision 1.1

12.0 Legacy Functional Blocks

This chapter briefly describes the following blocks, which provide legacy device functions:

Floppy Disk Controller (FDC)

Parallel Port (PP)

Serial Port1 and 2 (SP1 and SP2)

Keyboard and Mouse Controller (KBC)

For details on the general implementation of each legacy block, see the SuperI/O Legacy Functional Blocks datasheet.

The register maps in this chapter use the following abbreviations for Type:

R/W

= Read/Write.

= Read from register (write to the same address is to a different register).

= Write (see above).

= Read Only.

= Write Only. Reading from the bit returns 0.

R/W1C = Read/Write 1 to Clear. Writing 1 to a bit clears it to 0. Writing 0 has no effect.

R/W1S = Read/Write 1 to Set. Writing 1 to a bit sets its value to 1. Writing 0 has no effect.

12.1 FLOPPY DISK CONTROLLER (FDC)

12.1.1 General Description

The generic FDC is a standard FDC with a digital data separator; it is software compatible with the

µDP8473 and N82077.

The PC87373 FDC supports 14 of the 17 standard FDC signals described in the generic Floppy Disk Controller (FDC) chap-

ter, including:

• FDC supportS FM and MFM modes. To select either mode, set bit 6 of the first command byte when writing to/reading

from a diskette, where:

— 0 = FM mode

— 1 = MFM mode

• A logic 1 is returned during LPC I/O read cycles by all register bits, reflecting the state of floating (TRI-STATE) FDC pins.

Exceptions to standard FDC are:

• Automatic media sense using MSEN0 and MSEN1 signals is not supported.

• DRATE1 is not supported.

• DR1 is not supported.

• MTR1 is not supported.

Table 52 lists the FDC functional block registers. All registers are VDD3 powered.

Table 52. FDC Register Map

Offset1

Mnemonic

Type

00h

SRA

Status A

01h

SRB

Status B

02h

DOR

Digital Output

R/W

03h

TDR

Tape Drive

R/W

04h

MSR

Main Status

DSR

Data Rate Select

05h

FIFO

Data (FIFO)

R/W

PC87373 Folha de dados(PDF) 140 Page - National Semiconductor (TI)

PC87373 Folha de dados(HTML) 140 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Folha de dados Download

Ligação URL