Tandy 1000
Technical Reference Manual
inter
8272A
Table
12.
Status
Registers
MD
SN
executing
the
SCAN
Command.
If
the
FDC
can
no!
lind
a
Sector
on
the
cylinder
which
meets
the
condillon,
then
thiS
flag
is
set
r-
BC
ThiS
bit
IS
related
wilh
the
NO
bit
and
when
the
content
0'
C
on
the
I
medium
IS
different
Irom
that
stored
! In
the
lOR
and
the
conlent
of
C
IS
IFF.
tilen
thiS
flag
is
set
SH
During
execution,
tile
SCAN
Command,
d
the
condl!lon
01
equal"lssatls1Ied.til1sllag
STATUS REGISTER 3
D~1
F~'I'l'----'---I'
-'FT---l~~,s
bit
is
used-~~~-i-~;te
the
, -
..
~t
J~I~~US
of Ihe Fault SIgnal from fhe
0
6
:
~~~:cted
i
WP
;
:~~~u~I~;St~:~r:~ei;~~~:~~e~:ignal
i
~-J---~
-I tram fhe
FDD
---.J
I
Os
I
Ready
:
ROY
ThiS
bit
IS
used
to
Indicate
the
status
I
~
"
..
. ....' jof fhe Ready Slgoal tram-,-he
-"D~~j
o:i
Tra-c;-O- - ------I--
t
TO
1 ThiS
blt~s
usedto
Indicate
the
status
j
t
of
the
Track
0 Signal
from
the
FDO
r 0
3
Two
Side
TS I ThiS
bit
IS
used
to
Indicate
the
slatus
I I I
01
the
Two
Side
slgnallrom
the
FOD
1
_-
j -+-- -
02 I
Head
I
HD
i
This
bit
IS
used
to
Indicate
the
status
I
~
I
Address;
:
of
Side,
Select
signal
to
the
FOO
I
D-;-+-uoifs~,;c:t,
r.
_US11
T
_
hj_~.
bll
'5
used
fo
'ndlcafe
'he
st.tus.
_ + _
__
0_'
the
Unl!
Select
1Signal
tothe
FDD
I-Do U-;;,lSelectO - US 0
:~:~:~~:f~se~~:~;~~~~:~~~~~:~~~s
r---
BIT
--.-----r--~-
--
--_.
__
.---
..
-
I
~o~
,o~··'~~!!m::~~~;;,~:::"
0.,.
, I
Writable
I
WRITE
DELETED
DATA
or
Formal
A
I
I I
Cylinder
Command,
lithe
FDC
.1
'
-.-
__
I I
detects
a
write
protect
Signal.
from
~___
_
__
_ 1
__
---l~he
FDO,
then
thiS
flag
IS
set
I
Do
:
Missing
MA
i II
the
FOe
cannol
detect
the
10
1
Address
I
Address
Mark
alter
encountering
the
I
I
:
Mark
!,
Index
hole
tWIce,
then
thiS
Ilag
IS
set
f----.~------~--1
I I r
the
FOC
cannot
detect
the
Data
Address
Mark
or
Deleted
Data
I I
:tdld::ss:~:rt~~I;,i~~~a~;
(~,~S~~~O
I
..
.l_
_
Add,ess
Mark
In
Dala F,eld) of
I::
i
'",,'0
,::ro,
:::::~~;;o":,""
I
I
Mark
'
SCAN
Command,
II
the
FOC
I
encounters
a
Sector
which
contains
i a
Deleted
Data
Address
Mark,
Ihis
___
~__
flag
'5
se'
I
°5
i
DO
:
~~~h~a~~~e~~\~~l~
~h~RI~a~rlr:~~~
'I-D:-;:~~n:,e'd
we
t Th,s
b'l
'5
rela'ed
w"h
Ihe
"I-Obi"
, I
Cylinder
and
when
the
contents
01
C
on
the
,I
r
:et~I~~~,
~~II~e~~a~
:~os:tthat
stored
i
During
executing
the
READ
10
Com
j
mand,
if
the
FDC
cannot
read
the
I 10
field
WIthout
an
error,
then
this
flag
IS
set
During
the
execution
of
the
READ
A
I
~:~it~~e~a~~~::nl;ui~~~~h:~:~sg
flag
is
set
OR
ND
Not
Ready
Equipment
Check
0
5
Seek
End
D,
0
7
=0
and
0
6
= 1
Abnormal
Termination
01
Com
mand,
(AT).
Execulion
of
Command
i
was
started,
but
was
not
successfully
completed
0
7
=1
and
06=
0
Imalid
Command
issue,
(ICl
Command
which
was
issued
was
never
stat1ed
---Iil-T
---,--
-----
--_._.,
--
-.----,--------1
DESCRIPT.ION...
I
NO
NAME_LS~B~Ll___
__
---J
STATUS REGISTER
0.
~
0
7
Interrupl
Ie
07
==
0
and
0
6
==
0 . I
Normal
Termmatlo.n
01
Command,
I
(Nn.
Command
was
completed
and
properly
executed
:1-
0"".
Run
D
J
..
O
2
No
Data
I
i
D
7
= 1
and
0
6
= 1
Abnormal
Termination
because
l
dunn
g
command
executIon
the
ready
signal
from
FDD
changed
-f
SE
i
~:~n
the
FOe
Co";~I~~
I
I i
SEEK
Command,
lhis
flag
is
set
to
1
!
Ilh'9h)
!
EC
t11-~----;;~;
S"i9~~-li~-r;~-;i-\;~dl~~~the1
I FDD.
or
it
the
Track
a
Signal
fails
to
I
I
occur
after
77
Step
Pulses
(Recali-
I
+~rale
Command)
then
thiS
flag
is
se~J
I
When
the
FDD
is In
the
not-ready
:
!
Slale
and
a
read
or
write
command
IS
:
I
Issued,
this
flag
IS
sel
II a
read
or
\
write
command
is
Issued
to
Side
1
I
of
a
Single
sided
dme,
then
j
Isset
i ThiS
flag
IS
used
to
Indicate
tile
_
--1-
stale
of
the
head
at
Interrupt
f---~~~+---
....
----c+----:-c::-='-
-
~:i::e~~~~~:~bue~e:t
~~tie~~~cp~te
a
6-235
AFN·01259C
To Next Page
Loading...
Need help?
General
