Commodore Plus 4 - Page 372

360 Using Peripheral Devices
2058
205A
205C
205E
2061
2063
2066
2068
206B
206E
206F
2071
2074
2076
2079
207B
207E
2081
2083
2086
2088
208B
208E
C9
D0
A9
20
A9
20
A2
20
9D
E8
D0
20
A9
20
A9
20
20
A9
20
A9
20
20
00
30
18
08
B4
62
96
00
A5
00
F7
AB
08
Bl
E2
93
AE
08
Bl
EF
93
AE
FF
FF
FF
22
FF
FF
FF
FF
FF
FF
FF
CMP
BNE
LDA
JSR
LDA
JSR
LDX
JSR
STA
INX
BNE
JSR
LDA
JSR
LDA
JSR
JSR
LDA
JSR
LDA
JSR
JSR
BRK
#$30
$2074
#$08
$FFB4
#$62
$FF96
#$00
$FFA5
$2200,X
$2068
$FFAB
#$08
$FFB1
#$E2
$FF93
$FFAE
#$08
$FFB1
#$EF
$FF93
$FFAE
If no error, the result will be $30.
If not, error has been detected so quit.
Disk drive device number.
Tell drive to talk.
Access data channel (to get results of
Ul).
Send as- secondary address to drive.
.X counts the bytes received.
Receive a byte from the drive.
Store in directory buffer.
Increment byte count.
Get one whole sector.
Tell drive to stop talking.
Disk drive device number.
Ttell drive to listen.
Close command for channel 2.
Send as secondary address to drive.
Tell drive to stop listening.
Disk drive device number.
Tell drive to listen.
Close command for channel 15.
Send as secondary address to drive.
Tell drive to stop listening.
Stop processing.
The Ul command is stored as data.
>2100
>2108
55 31 3A 32 2C 30 20 31 : |U1:2,O,1|
38 2C 31 00 00 00 00 00 :18,1 |
The Datassette Tape Recorder
The Datassette is a specialized tape recorder for use with Commodore computers
only. The Datassette designed for use with the Plus/4 is called the 1531. A
Datassette can be used to store and retrieve programs and data. Working with
tape is slow, and the capacity of even the longest recommended tape (30 minutes)
is limited. However, cassette tapes are not as easily destroyed as diskettes (in the
mail or in the hands of young children). The Datassette is also much less
expensive than a disk drive, and cassette tapes are cheaper than diskettes. For the
lower-budget computer user, or a beginner just starting to program, a Datassette
may be a good investment.
Files on tape can, but need not, be identified with names. It is generally a good
idea to give every file on a tape a name unless only one file is to be stored on the
tape. When you access a tape file, the computer begins searching the tape from
wherever it is sitting. In other words, the computer does not rewind the tape, so
you must be careful to position the tape before you ask the computer to access a
file.