Page 60 of 62
SBasic User's Manual SBasic Version 2.7 Page 60
Printed: December 5, 1999
Character I/O on the 68hc11
The PRINT and OUTCH statements generate code for sending characters
and text to some type of host, using library routines. For the
68hc11, this defaults to routines that use the SCI.
Note, however, that SBasic does not actually set up the SCI for serial
transfers. Thus, it is not usually enough to simply PRINT a string;
your code must first (as a minimum) enable the SCI transmitter and set
the SCI baud rate.
This same requirement exists for the INKEY() function. Before your
code can successfully invoke the INKEY() function, it must first
enable the SCI receiver and set the SCI baud rate.
Fortunately, this is a simple task. Assuming the 68hc11 target system
uses an 8.0 MHz crystal, the following statements will set up the SCI
for 9600 baud and enable the SCI receiver and transmitter:
include "regs11.lib"
main:
pokeb baud, $30 ' 9600 baud
pokeb sccr2, $0c ' enable rcvr and xmtr
print "Hello, world!" ' now say something
If your 68hc11 target system uses a crystal frequency other than 8.0
MHz, consult the Motorola technical literature for the proper data
value to POKEB into the BAUD register.