Data Electronics - Radio Shack TRS-80 Service Manual

INDEX
PULSE
WRITE
PROTECT
TRACK
PULSE SHAPING
NETWORK
SINGLE SIDED
HEAD ASSEMBLY
<Ci------0_0 _ _ _
-I
\,:~1~:C:1-<H~0
1----------------.....J
DRIVE
MOTOR
ENABLE
1------\::-----il
~t'INDLE DRIVE
INTERFACE ONTROL
CONTROL
DIRECTION
STEP
WRITE
DATA
WRITE ENABLE
READ DATA
POSITION ER
CONTROL
WRITE BUSY
WRITE/ERA
CURRENT SOU
AND WAVEF
GENERA TO
REA
FIGURE 4. FUNCTIONAL BLOCK DIAGRAM
DATA ELECTRONICS
Information can be recorded on the diskette using a double-
frequency code. Figcrre 5 illustrates the magnetization pro-
files in each bit cell for the number sequence shown.
The erase gaps provide an erased guard band on either side
of the recorded track. This accommodates the tolerances
in track positioning.
BIT PATTERN
-H
I
I
I
I
I
BIT CELL
~
I
I
I
I
I
All signals required to control the data electronics are pro-
vided by the user system and are shown in the Block Dia-
gram ( Figure 4). These control signals are:
*
SELECT
*
WRITE ENABLE
*
WRITE DATA
The READ DATA composite signal is sent to the user
system via the interface.
FIGURE 5. FM RECORDING
98