Read/Write Operations; Write Operation: Pc Board 20292-Xxx; Mfm Write Data; Figure 19: Data Signal Driver/Receiver Combination - Seagate ST212 Product Manual

1\\'0 pairs of balanced signaIs are employed for data transfer: MFM WRITE
DATA and MFM READ DATA. Data transfer Hnes between the host system
and the drive are differential in nature and may not be multiplexed. Refer to
1àble
2 for data transfer pin assignments and Figure 6 for a host/drive inter-
conection example.
6.0
READ/WRITE
OPERATIONS
20 FT. MAX
HIGH
TRUE
FIGURE 19:
Data Signal
Driver/Receiver
Combination
FLAT CABLE OR TWISTED PAIR
6.1 WRITE OPERATION: PC BOARD 20292-XXX
WRITE
GATE
WRITE DATA PROCESSING
READIWRITE
READIWRITE
HEADS
LSI (IC6H)
MFM
DIFFERENTIAL
WRITE DATA
HEAD
SELECT
FIGURE 20:
FROM INTERFACE
Write Operation
PC Board 20292-XXX
In order to Write, the following conditions must be satisfied:
WRITE FAULT inactive
SEEK COMPLETE active
READY active
DRIVE SELECT active
Write Gate active
6.1.1
MFM WRITE DATA
WRITE DATA is transmitted by a differentiai pair which defines the transitions
to be written on the disco The
+
MFM WRlTE DATA Hne going more positive
than the -MFM WRITE DATA Hne is the active transition. This signal must
be driven to an inactive state when in READ mode.
22
ST212 PRODUCT MANUALIRev. B