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A-22 HP
9895A
Disc Memory Command Set
Control Commands
Universal or Selected Device Clear
Type:
Purpose:
Description:
HP-IB Sequence:
ATN
Control.
A clear places the 9895A in a known state. Thus, it is useful
when initializing a system on power up or after a host sys-
tem crash. The clear also allows a power up DSJ of 2 to be
cleared by sending a single byte. Since a clear updates the
device's HP-IB address, it is useful if the system is being
re-configured.
Upon reception of either a universal or selected device
Clear command, the 9895A stops handshaking with the
HP-IB, parallel poll response is disabled and the following
are performed:
1. The PHI is reset,
2. HP-IB is updated from the device address on the
controller board,
3. Stat 1 is cleared,
4. Stat 2 is updated appropriately,
5. DSJ set to 0,
6. All drives are re-calibrated to physical track 0,
7. The target address is set to cylinder 0, head 0, sec-
tor 0/1 for HP /IBM format,
8. Disable HP-IB parity checking.
Universal Device Clear
ATN
P P
I POOI0IOO
P P
Universal IDE
Selected Device Clear
ATN
P P
IPOI~DDRSI
Pnmary
I
POOOOIOO
I
~ ~
Selected
Device
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