User Commands - Commodore 1541 User Manual
Hide thumbs
Also See for 1541:
- User manual (81 pages) ,
- Maintenance manual (36 pages) ,
- Technical manual (38 pages)
Table of Contents
Advertisement
ALTERNATE
FORMATS:
PRINT#l5
,"
B-E: ";channel # ;drive #
;track
# ;sector#
PRINT#15,
"
B-E:channel # ,drive #,track #,sector#"
EXAMPLES
:
Assuming you
've
written a machine language program onto Track 1, Sector
8 of a
diskette
,
and would like to run
it
in buffer number 1 in disk memory
(starting at
$0400
hexadecimal
,
you could
do
so
as follows
:
110 OPEN 15,8,15
Open
command channel
120 OPEN
2,8,2,
"#
1"
Open direct access channel to
buffer
I
Load Track
1,
Sector 8 in it &
execute
Tidy up after
130 PRINT#l5,
"
B-E";2;0;1;8
140 CLOSE 2
150 CLOSE 15
160END
USER COMMANDS
Most User
commands
are intended to be used as machine language JMP
or
Basic
SYS
commands
to machine language programs that reside inside the disk
memory.
However,
some
of them have
other
uses
as
well
.
The Userl and User2
commands
are used
to replace the Block-Read
and
Block-Write
commands,
UI
re-starts
the 1541
without
changing
its variables
,
UJ
cold-starts
the 1541 almost as if it had been turned
off
and on
again, and UI- speeds up the 1541 when used with the VIC 20 only
. (Note:
VIC 20
owners
don 't have to use UI-; the 1541 works with the VIC 20, with or without this
command.)
User Command
Ul or UA
U2 orUB
U3
or UC
U4 or UD
US
or UE
U6
or UF
U7
orUG
U8 or UH
U9
or UI
U:
or UJ
Ul+
UI-
replaces Block-Read
replaces Block-Write
Function
JMP $0500
(same
as SYS 5*256
,
but within the 1541
itself.)
JMP $0503
(SYS
5*256
+
3)
JMP $0506
(
"
5*256
+
6)
JMP $0509
( "
5*256
+
9)
JMP $050C
("
5*256+ 12)
JMP $050F (
"5*256+
15)
1541 NM!
(non-maskable
intelTUpt-warm start)
1541 reset
(cold
start, allow 2 seconds before next
command.)
restore 1541 to usual speed
speed 1541 up by 25% when used with VIC 20 only
.
By loading these memory locations with another machine language JMP
command.
such as JMP $0520
,
you can create longer routines
th~t
operate in the disk's
memorY
along with an easy-to-use jump table.
78
fORMAT FOR USER
COMMANDS:
PRINT#l5
, "
Ucharacter"
\Where
"
character" defines
one
of the preset user commands listed
above.
E)(AMPLES
:
PRINT#l5,
"
U:"
PRINT#15 ,"U3"
79
Preferred form of DOS RESET
command
Execute program at
start of
buffer
2
Advertisement
Table of Contents
