ZiLOG System 8000 Hardware Reference Manual page 136

HRM
2ilog
HRM
Protect function is enabled by a switch on the operator
panel.
SEEKEND - Seek End is
a
combination of On Cylinder or Seek
Error indicating that a seek operation has terminated.
HOLD/PICK - Applying ground to the Pick and Hold lines
enables the first SMD in a Power-Up sequence. Once
up
to
speed, the PICK- signal is transferred to the next active
SMD.
BUSY - If the devicE~ is already reserved and/or selected, a
BUSY is issued to the controller on the SMD A cable and
SELECTED- issued on the SMD B cable.
WRITEDATA (0-3) - This line carries data (NRZ FORM) which is
to be recorded on the disk pack.
READDATA (0-3) - This line transmits the recovered data to
the controller in the NRZ form. SERVOCLK- (0-3) The Servo
Clock is a phased-locked 9.677 MHz clock generated from
dibits on the SMD and used to generate write data. This sig-
nal is available at all times to the controller.
READCLK (0-3) - The Read Clock defines the beginning of
a
data cell. It is an internally derived clock signal and
is
synchronous with the detected data. It is transmitted con-
tinuously to the controller.
WRITECLK (0-3) - The Write Clock signal is synchronized to
the NRZ data. The Write Clock is the received Servo Clock
which is retransmitted by the controller during a write
operation.
4.5.4. Cartridge Tape Controller:
The tape controller is
the intelligent interface between the System 8000 CPU and
the tape drives (also called decks). The controller derives
its intelligence from its on-board Z80B microprocessor.
Figure 4-7 shows the basic relationship between the con-
troller and both the System 8000 bus (ZBI) and the tape
decks. Information flows between the controller and the CPU
over the ZBI (mating connectors P1/J14). The flow of infor-
mation between the controller and a selected tape drive is
through mating connectors P2/J24 of slot 4 only of the sys-
tem backplane. Figure 4-8 shows the allocation of the I/O
space of the controller.
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Zilog
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