HP Dc7700 HP Compaq dx7300 and dc7700 Business PC Technical Reference Guide, 1 - Page 85

Table 5-5., Diskette Drive Interface Control Registers, Primary, Address, Second., Register

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Input/Output Interfaces Table 5-5. (Continued) Diskette Drive Interface Control Registers Primary Second. Address Address Register 3F4h 374h Main Status Register (MSR): Request for master (host can transfer data) (active high) Transfer direction (0 - write, 1 = read) non-DMA execution (active high) Command busy (active high) Reserved Drive 1, 2 busy (active high) Data Rate Select Register (DRSR): Software reset (active high) Low power mode enable (active high) Reserved (0) Precompensation select (default = 000) Data rate select (00 = 500 Kb/s, 01 = 300 Kb/s, 10 = 250 Kb/s, 11 = 2/1 Mb/s) 3F5h 375h Data Register: Data 3F6h 376h Reserved 3F7h 377h Digital Input Register (DIR): DSK CHG status (records opposite value of pin) Reserved (0's) Configuration Control Register (CCR): Reserved Data rate select (00 = 500 Kb/s, 01 = 300 Kb/s, 10 = 250 Kb/s, 11 = 2/1 Mb/s) R/W R W R/W -R W NOTE: The most recently written data rate value to either DRSR or CCR will be in effect. Technical Reference Guide www.hp.com 5-7

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Technical Reference Guide
www.hp.com
5-7
Input/Output Interfaces
NOTE: The most recently written data rate value to either DRSR or CCR will be in effect.
3F4h
374h
Main Status Register (MSR):
<7> Request for master (host can transfer data) (active high)
<6> Transfer direction (0 – write, 1 = read)
<5> non-DMA execution (active high)
<4> Command busy (active high)
<3,2> Reserved
<1,0> Drive 1, 2 busy (active high)
Data Rate Select Register (DRSR):
<7> Software reset (active high)
<6> Low power mode enable (active high)
<5> Reserved (0)
<4..2> Precompensation select (default = 000)
<1,0> Data rate select (00 = 500 Kb/s, 01 = 300 Kb/s, 10 = 250
Kb/s, 11 = 2/1 Mb/s)
R
W
3F5h
375h
Data Register:
<7..0> Data
R/W
3F6h
376h
Reserved
--
3F7h
377h
Digital Input Register (DIR):
<7> DSK CHG status (records opposite value of pin)
<6..0> Reserved (0’s)
Configuration Control Register (CCR):
<7..2> Reserved
<1,0> Data rate select (00 = 500 Kb/s, 01 = 300 Kb/s, 10 = 250
Kb/s, 11 = 2/1 Mb/s)
R
W
Table 5-5.
(Continued)
Diskette Drive Interface Control Registers
Primary
Address
Second.
Address
Register
R/W