Drive Interface Lines And Pin Assignments - Tandon TM848-1E User Manual

TABLE 3-1
DRIVE INTERFACE LINES AND PIN ASSIGNMENTS
Ground
Pin Signal
1
2 Write Current Switch
3 4 Motor On Control 1
5 6 Motor On Control 2
7
8 True Ready, (Motor On Control 3, Optional)
9 10 Two Sided (Strappable) (TM848-2E only)
11 12 Disk Change (Strappable)
13 14 Side Select (TM848-2E only)
15
16 In Use Indicator (Strappable)
17 18 Head Load Line/Motor Control
19 20 Index
21 22 Ready
23
24 Motor On Control 4
25 26 Drive Select 1 (Side Select Option, TM848- 2E only)
27 28 Drive Select 2 (Side Select Option, TM848-2E only)
29
30 Drive Select 3 (Side Select Option, TM848-2E only)
31 32 Drive Select 4 (Side Select Option, TM848-2E only)
33 34 Direction Select (Side Select Option, TM848-2E only)
35
36 Step
37
38 Write Data
39 40 Write Gate
A'"
An
Track 0
Lt.1. Lt~
43 44 Write Protect
45 46
Read Data
47 48 Alternate I/O
49 50 Alternate I/O
Write commands. When the signal logic level
is false (high), the input control lines and the
output status lines are disabled.
The Drive Select address is determined by a
select shunt on the circuit board. Drive Select
lines 1 through 4 provide a means of daisy
chaining a maximum of four drives to a con-
troller. Only one can be true (low) at a time.
An undefined operation might result if two or
more drives are assigned the same address or
if two or more Drive Select lines are in the
true (low) state simultaneously. A Drive
Select line must remain stable in the true
(low) state until any operation in progress
(Step, Read/Write) is completed.
Using Side Select options 1B through 4B,
Drive Select lines may be used as Side Select
lines for the TM848-2E (see Section 3.6).
3-3
DIRECTION SELECT AND STEP LINES
(TWO LINES)
When the drive is selected, a true (low) pulse
on the Step line, with a time duration greater
than one microsecond, initiates the access
motion. The direction of motion is determined
by the logic state of the Direction Select line
when a step pulse is issued. The motion is
toward the center of the disk if the Direction
Select line is in the true (low) state. The direc-
tion of motion is away from the center of the
disk if the Direction Select line is in the false
(high) state.
To ensure proper positioning, the Direction
Select line should be stable at least 1 micro-
second prior to the corresponding rising edge
of the step pulse, and remain stable 100 nano-
seconds after it.