W83877ATG Nuvoton Technology Corporation of America, W83877ATG Datasheet - Page 38

• Manufacturer Part Number: W83877ATG
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of W83877ATG

• Lead Free Status / RoHS Status: Supplier Unconfirmed

Media ID1 Media ID0 (Bit 7, 6):
These two bits are read only. These two bits reflect the value of CR8 bit 3, 2.
Drive type ID1 Drive type ID0 (Bit 5, 4):
These two bits reflect two of the bits of CR7. Which two bits are reflected depends on the last drive
selected in the DO REGISTER.
Floppy Boot drive 1, 0 (Bit 3, 2):
These two bits reflect the value of CR8 bit 1, 0.
Tape Sel 1, Tape Sel 0 (Bit 1, 0):
These two bits assign a logical drive number to the tape drive. Drive 0 is not available as a tape drive,
and is reserved as the floppy disk boot drive.
5.2.5
The Main Status Register is used to control the flow of data between the microprocessor and the
controller. The bit definitions for this register are as follows:
5.2.6
The Data Rate Register is used to set the transfer rate and write precompensation. The data rate of
the FDC is programmed by the CC REGISTER for PC-AT and PS/2 Model 30 and PS/2 mode, and
not by the DR REGISTER. The real data rate is determined by the most recent write to either of the
DR REGISTER or CC REGISTER.
7
6
Main Status Register (MS Register) (Read base address + 4)
Data Rate Register (DR Register) (Write base address + 4)
TAPE SEL 1
5
4
0
0
1
1
3
2
1
0
FDD 2 Busy, (D2B = 1), FDD number 2 is in the SEEK mode.
FDD 0 Busy, (D0B = 1), FDD number 0 is in the SEEK mode.
FDD 1 Busy, (D1B = 1), FDD number 1 is in the SEEK mode.
FDD 3 Busy, (D3B = 1), FDD number 3 is in the SEEK mode.
FDC Busy, (CB). A read or write command is in the process when CB = HIGH.
Non-DMA mode, the FDC is in the non-DMA mode, this bit is set only during the
execution phase in non-DMA mode.
Transition to LOW state indicates execution phase has ended.
DATA INPUT/OUTPUT, (DIO). If DIO= HIGH then transfer is from Data Register to the processor.
Request for Master (RQM). A high on this bit indicates Data Register is ready to send or receive data to or from the processor.
If DIO = LOW then transfer is from processor to Data Register.
TAPE SEL 0
0
1
0
1
- 31 -
W83877ATF/W83877ATG
Publication Release Date:November 2006
DRIVE SELECTED
None
1
2
3
Version 1.0