W83977EG-AW Datasheet, PDF (92/142 Pages) Nuvotem Talema – These products are not designed for use in life support appliances

W83977EF-AW/W83977EG-AW
12.2 Logical Device 0 (FDC)
CR30 (Default 0x01 if PNPCSV# = 0 during POR, default 0x00 otherwise)
Bit 7 - 1: Reserved.
Bit 0: = 1 Activates the logical device.
= 0 Logical device is inactive.
CR60, CR 61 (Default 0x03, 0xf0 if PNPCSV# = 0 during POR, default 0x00, 0x00 otherwise)
These two registers select FDC I/O base address [0x100:0xFF8] on 8 byte boundary.
CR70 (Default 0x06 if PNPCSV# = 0 during POR, default 0x00 otherwise)
Bit 7 - 4: Reserved.
Bit 3 - 0: These bits select IRQ resource for FDC.
CR74 (Default 0x02 if PNPCSV# = 0 during POR, default 0x04 otherwise)
Bit 7 - 3: Reserved.
Bit 2 - 0: These bits select DRQ resource for FDC.
= 0x00 DMA0
= 0x01 DMA1
= 0x02 DMA2
= 0x03 DMA3
= 0x04 - 0x07 No DMA active
CRF0 (Default 0x0E)
FDD Mode Register
Bit 7: FIPURDWN
This bit controls the internal pull-up resistors of the FDC input pins RDATA, INDEX, TRAK0,
DSKCHG, and WP.
= 0 The internal pull-up resistors of FDC are turned on.(Default)
= 1 The internal pull-up resistors of FDC are turned off.
Bit 6: INTVERTZ
This bit determines the polarity of all FDD interface signals.
= 0 FDD interface signals are active low.
= 1 FDD interface signals are active high.
Bit 5: DRV2EN (PS2 mode only)
When this bit is a logic 0, this indicates that a second drive is installed and is reflected in status
register A.
Bit 4: Swap Drive 0, 1 Mode
= 0 No Swap (Default)
= 1 Drive and Motor sel 0 and 1 are swapped.
Bit 3 - 2 Interface Mode
= 11 AT Mode (Default)
= 10 (Reserved)
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