Commodore Plus 4 - Page 383

The Printer
371
2015
2017
2019
201C
201E
2021
2023
2026
2029
202C
202E
2030
2032
2035
2037
203A
203C
B0
A9
20
A2
20
B0
20
20
20
F0
C9
D0
20
A9
20
B0
00
69
0D
D2
02
C6
5D
CF
D2
B7
F5
40
4E
CC
02
C3
44
FF
FF
FF
FF
FF
FF
FF
BCS
LDA
JSR
LDX
JSR
BCS
JSR
JSR
JSR
BEQ
CMP
BNE
JSR
LDA
JSR
BCS
BRK
$2080
#$0D
$FFD2
#$02
$FFC6
$2080
$FFCF
$FFD2
$FFB7
$2023
#$40
$2080
$FFOC
#$02
$FFC3
$2080
If error, go to error message routine.
Carriage return character.
Send to screen.
Logical file number of file.
Set to input channel.
If error, go to error message routine.
Get a character from the file.
Send to the screen.
Kheck the status byte.
If zero, continue.
Conpare to end-of-file.
If not, go to error message routine.
Reset I/O channels.
Logical file number of file.
CLOSE.
If error, go to error message routine.
Stop processing.
This routine sends the message ERROR to the screen:
2080 20 E7 FF JSR $FFE7
2083 A2 05 LDX #$05
2085 BD F8 20 LDA $20F8,X
2088 20 D2 FF JSR $FFD2
208B CA DEX
208C 10 F7 BPL $2085
208E 00 BRK
These data are needed:
Close all the files and reset I/O
channels.
Length of message.
Get a character of message.
Send to the screen.
Decrement the pointer.
If not done, go on.
Stop processing.
>20F8 52 4F 52 52 45 OD 00 00
>2100 44 41 54 46 49 4C 00 00
The Printer
Numerous printers are available for use with the Plus/4. Commodore manufac
tures a number of them, but other vendors' printers can also be used. All of
Commodore's printers are intelligent and are connected directly to the serial port.
They can be daisy-chained with other serial devices (e.g., a disk drive). Most
other vendors offer an interface cable that connects their printer to the serial port
and emulates a Commodore printer. Commercial software (e.g., word proces
sors) generally assumes that the printer is configured in this way.
Some vendors may interface through an RS232 connection. Programming for
such printers requires using the RS232 port described in another section of this