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Troubleshooting and Diagnostics
7936 and 7937
Table 8-4. Read/Write System Test Fixture, Mnemonics
(1
of 2)
PIN
NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
8-46
MNEMONIC
BIT 8
FRAME
RDGT-H
DATAEN
AGND
DPIRQ-L
-S.2V
FIL
TRAN+
WGTO-L
RDEN-H
WDATA-H
SOS-L
SIGNAL
Bit 8
Frame
Read Gate
Data
Enable
Analog
Ground
Data Proc
Interrupt
Request
-S.2V
Fault Ignore
Read
Transition
Write
Gate
Output
Read
Enable
Write
Start of
Sector
DESCRIPTION
A count during a sector. A convenient
trigger for viewing other read/write wave
forms.
Bit word in sync field to begin start of
header.
Only looked for approximately
half-way through sync field. Triggered by
sector read.
Internal to read/write controller. Not used.
Frame asserts data enable (header in-
cluded). This is the first sync bit out of the
read/write controller.
Analog ground
Read/write controller has received fault
condition, for example write holdoff. For
development only.
-S.2V
Read/write controller will ignore all fault
conditions. CAUTION: allows writing in
the sampled servo area.
Rises each time a flux reversal is detected
in the read/write path. The toggle switch
on the test PCA must be set to the ON
position to monitor this signal.
Active when a write operation is occurring.
Gates write current to the data heads.
Tells PLL to lock onto data instead of WC.
The actual data being written to the heads.
(Leading edge creates flux reversal.) Signal
is not precompensated.
Alerts the read/write controller to begin a
read or write.
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