NorthStar HORIZON Manual page 62

DISK CONTROLLER STATUS BYTES
There are three status bytes that can be read on the Data Input
Bus.
A-Status
.----7----.----.----.----.----.----.----.
I
SF
I
IX
I
DO
I
MO
I
WI
I
RE
I
SP
I
BD
I
._---~----~----~----~----~----~----~---_.
B-Status
---------------------------------------
.
.
.
.
.
. .
I
SF
I
IX
I
DD
I
MO
I
WR
I
SP
I
WP
I
T0
I
._---~----~----~----~----~----~----~---_.
C-Status
----.----.----.----.----.----.----.----
I
SF
I
IX
I
DD
I
MO
I
SC
._---~----~----~----~----~----~----~---_.
SF Sector Flag: set when sector hole detected, reset by
software.
IX Index Detect: true if index hole detected during previous
sector.
DO Double Density Indicator: true if data being read is encoded
in double density.
MO Motor On: true while motor(s) are on.
WI Window: true during 96-microsecond window at beginning of
sector.
RE Read Enable: true while phase-locked loop is enabled.
BD Body: set when sync character is detected.
WR Write: true during valid write operation.
SP Spare: reserved for future use.
WP write Protect: true while the diskette installed in the
selected drive is write protected.
SC Sector Counter: indicates the current sector position.
T0 Track 0: true
if
selected drive is at track zero.
North Star HORIZON Computer
62