SAVING PROGRAMS
SECTION 3
Page 3-1 RPC -320
Figure 3-1 W3 autorun jumper
INTRODUCTION
Program s are stored in an EPRO M in socket U6. You
can store one or mor e program s, depending upon
EPROM size. A BASIC program can call another when
a 512K byte EPROM is used.
M a x im u m p ro g r am s iz e th a t c a n b e r un a t a n y o n e t im e
is about 62K, not including space for variables. 32K
bytes is the maximum program size when a 29C256 IC
t yp e is u se d to s av e a p r o gr a m .
A conservative rule to determine program memory
requirements is one line requires 40 bytes. 32K bytes
would stor e 800 lines of co de. Your application cou ld
be significantly more or less, depending upon the
number of comm ands/line, com ments, and pr int
statements.
Despite the fact you may have a 128K or 512K RAM
installed, the maximum progr am size RPBASIC-52 can
r u n at on e ti m e i s a b ou t 6 0 K ( in c lu d in g r oo m f or s om e
variable storage). T he table below shows the maximum
capacity, maximum number of program lines, program
size at one time, and number of program s for an
EPROM type.
EPROM
Max
Prog
Max
No.
type
Cap.
lines
Bytes
Progs
29C256
30K
400
32K
1
29C040
509K
12400
62K
8
One program can call another using the EXECUTE
n
command.
n
is from 0 to 7, depending upon the
EPROM type.
NOTE:
When a program calls another, the old program
is completely replaced. All variables and
arrays are clear ed (set to 0).
To keep variables, you m ust save them before calling the
new progr am. When the new program is running, these
variables are restored. Use PEEK and P OKE to read
and save numbers and strings. See
Chapter 5, STORING
VARIABLES IN RAM
for more inform ation.
Binary data is saved and read from the EPR OM using
BSAVE a nd BLOA D com mands. The EP ROM has a
limited number of write cycles (about 1000), so wr iting
i nf o rm a ti on s ho u ld b e k e pt to a m in im u m .
A flash EPROM is non-volatile (retaining data even
when power is disconnected), having an unlimited
numbe r of re ad cycles an d a limited nu mber of write
cycles (about 1,000). A program is not run fr om
EPROM . It is transferred to RAM and run from there.
Prog ram s in RAM can be m odified. They ar e saved to
EPROM for execution later.
The RPC -320 can autorun on power up or r eset by
removing jumper (W9). W hen autorun is on, the
program in EPROM segment 0 is loaded into RAM and
begins to execute immediately.
This chapter discusses saving programs to EPR OM (U 6)
and program autoexecution.
SAVING A PROGRAM
For this example, assume you wanted to save the
f o ll ow i ng p r og r a m :
20 FOR N= 0 TO 2
3 0 PR I N T " H e ll o " ,
40 NEXT
5 0 P RI N T
If this progr am is not alr eady in, type it in now (or , if
you prefer, use your own progr am).
Type in the following command:
SAVE
RPBASIC-52 r esponds with:
Saving 35 bytes
Verifying --- OK