Signal Lines - Fujitsu M2301B Manual

4.5.3 Signal Lines
(1) Input Signal
(a) HEAD SELECT 0
~
2
These binary coded signal lines select one of eight data heads positioned
in the disk drive. However, the M2301 has only 4 data heads.
(b) DRIVE SELECT 1
~
4
These signal lines enable the input/output signals of the disk drive having
a matching logical unit number. Each line selects one drive. The signal line
of DRIVE SELECT 4 can be changed to the SEEK COMPLETE signal by
a switch setting on the PCB.
(c) DIRECTION
This indicates the seek direction of the data heads when STEP PULSES
are sent to the disk drive. When this signal is TRUE, it causes a seek in the
inner direction. And if this signal is FALSE, this causes a seek in the outer
direction (Toward track 0).
(d) STEP
This signal triggers the carriage to move the data heads one track in the
direction indicated by the 01 RECTION signal. The following three step
modes are provided.
i) Controlled Step Mode
If the step pulse rate is 1kHz or less, the drive performs a seek one
track in response to one STEP pulse from the controller.
iii Slave Step Mode
If the step pulse rate is more than 3kHz but less than 3MHz the drive
does not perform SEEK individually in response to each STEP signal
from the controller, but rather starts the seek operation after receiving
all STEP pulses from the controller. The drive will then move the
heads at high speed to the desired track according to an ideal velocity
curve stored in ROM.
When the SEEK operation is finished, the drive responds by sending
the SEEK COMPLETE signal.
Note: STEP RATE of 1kHz to 3kHz is prohibited.
iii) Return to Zero Mode
When the drive has received more than 255 step pulses in the slave
step mode, it performs a SEEK at normal speed to TRACK O.
(e) FAULT CLEAR
This signal line resets the write fault latch. The width of the pulse must be
grater than 100ns.
(f) WRITE GATE
This signal line gates write current to the selected data head.
(g) READ GATE
B03p·4605-0003A .... B
This signal line gates read data from the selected data head to the data
separator. Separated READ DATA and READ CLOCK are then provided
to the interface. READ GATE is valid when 10.0J.!s (6-byte) have elapsed
after READ DATE is active.
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