Commodore 1581 - CMD 6: Query Disk Format; CMD 7: Inquire Status

CMD 6—QUERY DISK FORMAT
BYTE
00
01
02
03
BIT 7
0
0
F
6
1
0
X
5
0
1
T
4
1
1
S
OFFSET
3
0
0
1
2
1
0
0
1
0
0
1
(OPTIONAL F-BIT SET)
0
1
0
N
SWITCHES: F—force flag (F = 1 steps the head with the offset specified in byte 03)
T—sector table (T= 1, send sector table)
N—drive number
X—don't care
S—side select
PROTOCOL: Burst handshake
CONVENTIONS: Determines the diskette format on any particular track. Also logs non-
standard diskettes (i.e. minimum sector addresses other than one).
OUTPUT: *burst status byte (no bytes will follow if there is an error)
**burst status byte (no bytes will follow if there was an error in compiling
MFM format information)
number of sectors (the number of sectors on a particular track)
logical track (the logical track number found in the disk header)
minimum sector (the logical sector with the lowest value address)
maximum sector (the logical sector with the highest value address)
interleave (always returns 1)
sector table (with T bit set, sector table is sent)
*status from track offset zero
**if F bit is set, status is from offset track
CMD 7—INQUIRE STATUS
BYTE
00
01
02
03
04
05
BIT 7
0
0
w
6
1
0
c
5 4 3
0 1 0
1 10
M 0 1
NEW STATUS (W-BIT CLEAR)
NEW ORA MASK (M-BIT SET)
NEW AND MASK (M-BIT SET)
2
1
0
1
1
0
0
0
0
1
0
N
SWITCHES: W—write switch (0 = write)
M—write AND/OR mask (04 new OR mask (M-bit set), 05 new AND mask
(M-bit set))
C—change (C = 1 and W = 0—log in disk C = 1 and W = 1—return
whether disk was logged, i.e. $B error or old status)
N—drive number
X—don't care
94