Commodore Plus 4 - Page 392

380 Using Peripheral Devices
. sooo
. 2002
. 2005
. 2007
. 2009
. 200B
. 200D
. 2010
. 2013
. 2015
. 2017
. 201A
. 201D
. 2020
. 2022
. 2024
. 2027
. 202A
. 202C
A9
20
A9
85
A9
85
20
20
DO
A9
20
20
20
C9
DO
20
20
DO
00
OD
D2
00
90
04
AE
Bl
B7
6B
67
93
CP
A8
OD
P6
AE
B7
54
FF
FF
FF
FF
FF
FF
FF
FF
This routine sends i
. 2080
. 2083
. 2085
. 2088
. 208B
. 208C
. 208E
20
A2
BD
20
CA
10
00
AE
05
P8
D2
P7
FF
20
FF
LDA
JSR
LDA
STA
LDA
STA
JSR
JSR
BME
LDA
JSR
JSR
JSR
CMP
BNE
JSR
JSR
BNE
BRK
#$0D
IFPD2
#$oo
$90
#$04
$AE
$FFB1
IPPB7
$2080
#$67
$PP93
$FFCF
$FFA8
#$0D
$201A
$FFAE
$PFB7
$2080
Carriage return character.
Send to the screen.
Load .A with zero.
Store in the status register.
Device number of printer.
Store in the current device number.
LISTN.
Read the status register.
If not zero, error.
Secondary address (7 ORed with $60)
SECND.
Read a keypress from the keyboard.
Send to the serial bus.
Compare with a carriage return.
If not equal, continue.
UNLSN.
Read the status register.
If not zero, error.
Stop processing.
in unlisten and prints out the error message:
JSR
LDX
LDA
JSR
DEX
BPL
BRK
IFFAE
#$05
$20F8,X
$FFD2
$2085
UNLSN.
Length of message.
Get a character of message.
Send to the screen.
Decrement the pointer.
If not done, continue.
Stop processing.
These data are the error message:
>20F8 52 4P 52 52 45 *0D 00 00 :|R0RKE...
The Modem and Other RS232 Devices
The RS232 port on the Plus/4 is not identical with that of the Commodore 64 and
VIC-20. As a result, RS232 interfaces that work with those computers may or
may not work with the Plus/4. In particular, the VIC modem and automodems
sold for use with the VIC and 64 do not work with the Plus/ 4. Commodore's new
1660 MODEM/300 is compatible with the Plus/4 as well as the Commodore 64
and VIC-20.
The commands described in this section have been verified with a 1660. The use
of other RS232 devices should be similar. Please refer to the documentation