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 14 - Status Register 0
00 - Normal termination of command. The specified
command was properly executed and completed without
01 - Abnormal termination of command. Command
execution was started, but was not successfully
10 - Invalid command. The requested command could
not be executed.
11 - Abnormal termination caused by Polling.
The FDC completed a Seek, Relative Seek or
Recalibrate command (used during a Sense Interrupt
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.
Unused. This bit is always "0".
Head Address The current head address.
Drive Select The current selected drive.