Tandy 1400LT Service Manual page 293

Pin
No. Name Function
Status Register 2
Not used. This bit is always 0 (low).
D6
CM (Control During execution of the Read Data or
Scan command, if the F D C encounters
a sector which contains a deleted data
address mark, this flag is set.
Mark)
~
D, DD (Data
If the F D C detects a CRC error in the
data field then this flag is set. Error in
Data Field)
D, WC (Wrong
This bit is related to the N D bit, and
when the contents of C(3) on the
medium is different from that stored in
the IDR, this flag is set.
Cylinder)
D,
SH (Scan During execution of the Scan
Equal Hit)
command, if the condition of "equal"
is satisfied, this flag is set.
D, SN (Scan During execution of the Scan
Not
Satisfied)
command, if the FDC cannot find a
sector on the cylinder which meets the
condition, then this flag is set.
D , BC (Bad
Cylinder)
This bit is related to the N D bit, and
when the contents of C on the medium
is different from that stored in the
IDR and the contents of C is FFH,
then this flag is set.
Do
M D (Missing When data is read from the medium,
Address
Mark in
Data Field)
if the F D C cannot find a data address
mark or deleted data address mark,
then this flag is set.
Pin
No. Name
Function
Status Register 3
D, FT
This bit is used to indicate the status
(Fault)
of the fault signal from the FDD.
D, WP (Write This bit is used to indicate the status
of the write protected signal from the
FDD.
Protected)
D, RY This bit is used to indicate the status
(Ready)
of the ready signal from the FDD.
D, T O This bit is used to indicate the status
(Track 0)
of the track 0 signal from the FDD.
D, TS This bit is used to indicate the status
of the two-side signal from the FDD.
(Two-Side)
D, H D (Head This bit is used to indicate the status
of the side select signal to the FDD.
This bit is used to indicate the status
of the unit select 1 signal to the FDD.
Address)
D, US, (Unit
Select
1)
Do US, (Unit
This bit is used to indicate the status
of the unit select 0 signal to the FDD.
Select 0)
Notes:
CRC
=
Cyclic Redundancy Check
IDR=Internal Data Register
Cylinder (C) is described more fully in the
Command Symbol Description.
F-24