STATUS REGISTER ENCODING
During the Result Phase of certain commands,
the Data Register contains data bytes that give
the status of the command just executed.
Table 15 - Status Register 0
NAME
Interrupt
BIT NO.
SYMBOL
IC
DESCRIPTION
7,6
00 - Normal termination of command. The specified
command was properly executed and completed
without error.
Code
01 - Abnormal termination of command. Command
execution was started, but was not successfully
completed.
10 - Invalid command. The requested command
could not be executed.
11 - Abnormal termination caused by Polling.
5
4
SE
EC
Seek End
The FDC completed a Seek, Relative Seek or
Recalibrate command (used during a Sense Interrupt
Command).
Equipment
Check
The TRK0 pin failed to become a "1" after:
1. 80 step pulses in the Recalibrate command.
2. The Relative Seek command caused the FDC to
step outward beyond Track 0.
3
2
Unused. This bit is always "0".
The current head address.
H
Head
Address
1,0
DS1,0
Drive Select
The current selected drive.
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