Data Transfer Signals; Data Transfer Line Equivalent Driver/Receiver - Tandon TM362 Manual

INDEX
The Index signal is provided once each revolution,
16.82 milliseconds nominal, to indicate the beginn-
ing of the track. Normally, this signal is false and
makes the transition to true to indicate Index. Only
the transition from logical false to logical true is valid.
READY
When true, the Ready signal, together with Seek Com-
plete, indicates that the drive is ready to read, write,
or seek, and the I/O signals are valid. When this line
is false, all controller-initiated functions are inhibited.
The typical time after power on for Ready to be true
is fifteen seconds. Track 0, Seek Complete, and Ready
come true sequentially during power on.
SELECT STATUS
Select status when true indicates that the drive has been
selected. Select status is dependent on location of the
program jumpers WI through W 4.
NOTE
Select status is the only output control line
on J2.
DATA TRANSFER SIGNALS
All lines associated with the transfer of data between
the drive and the host system are differential in nature
and may not be multiplexed. These lines are provid-
ed at the J2/P2 connector on all drives. Signal levels
are defined by RS-422A. Two pair of balanced lines
are used for the transfer of data: MFM Write Data
and MFM Read Data. Figure 3-12 illustrates the
driver/receiver combination used with the drive for
data transfer signals.
Timing requirements for Write Data and Read Data
signals are shown in Figure 3-13.
r
20 FT. MAXIMUM
l
(6.1 M)
FLAT RIBBON OR
TWISTED PAIR CABLE
HIGH
- - - - I
TRUE
26LS31 OR
EQUIVALENT
+
SIGNAL
- SIGNAL
FIGURE 3-12
26LS32 OR
EQUIVALENT
DATA TRANSFER LINE EQUIVALENT DRIVER/RECEIVER
3-15
>-_ _
HIGH
TRUE