Commodore Plus 4 - Page 219

Getting
Data
From
An
RS-232
Channel
When receiving data, the Commodore Plus/4 receiver buffer holds 127
characters before the buffer overflows. This is indicated by the RS-232
status word (ST from BASIC). All characters received when the buffer is
full
are lost. Obviously, it pays to keep the buffer as empty as possible.
Receiving RS-232 data at high speeds calls for use of machine lan
guage, since the speed of BASIC is a limitation.
CONTROL REG . (E =
CONTHOL REGISTER
Trie Control Register is used to select [he desired mode lor
itie 6551 The word length, number ot stop Oils, and clock
conuolsare all aalHrrnined by Ida Control Register, wmch is
aepicied in Figure l
STOP BITS -
■ =■;
1 =2&e
1SW
-8
11*1
= 5
.-■■■■
pBits
ptM
us*
obE
■■. ■
Word Lengm
a Psniy*
s d Wora Longtn
a mo P»ay
WORD LENGTH
Bil
.
;
■
■
.
i
0
1
DATA WORD
LENGTH
a
e
5
KECEIVEH CLOCK SOURCE
E-iemai Receiver Clock
< ETERNAL O.0CK
h-APOWARE RESET
PROGRAM RESET
-
0
£ ; s 3 0
Figure 1. Control Register Format
Basic Syntax:
Recommended: GET# If, <string variable>
NOT Recommended; INPUT# IS, <variable list>
210