Commodore 128D - C64 Mode

Programming
Function Keys In
C64 Mode
The four keys to the right side of the keyboard, just above the
numeric keypad, are called function keys. The keys are marked F1,
F3, F5 and F7 on the tops and F2, F4, F6 and F8 on the fronts. These
keys can be programmed—that is, they can be instructed to per
form a specific task or function. For this reason, these keys are
often called programmable function keys.
You must hold down the SHIFT key to perform the functions associ
ated with the markings on the front of the keys—that is, F2, F4, F6
and F8. Therefore, these keys are sometimes called the SHIFTed
programmable function keys.
The function keys in C64 mode do not have a printed character
assigned to them. They do, however, have CHR$ codes assigned. In
fact, each of them has two CHR$ codes—one for when you press
the key by itself, and one for wben you press the key while holding
down the SHIFT key To get the even-numbered function keys, hold
down the SHIFT key while.pressing the function key. For example, to
get F2, hold down SHIFT and press F1.
The CHR$ codes for the F1-F8 keys range from 133 to 140. However,
the codes are not assigned to the keys in numerical order. The keys
and their corresponding CHR$ codes are as follows:
F1 CHR$(133)
F2 CHR$(137)
F3 CHR$(134)
F4 CHR$(138)
F5 CHR$(135)
F6 CHR$(139)
F7 CHR$(136)
F8 CHR$(140)
You can use the function keys in your program in several ways. To do
this, you'll need to use the GET statement. (See Section 4 for a
description of the GET statement.) As an example, the program
below prepares the Fi key to print a message on the screen.
10 ? "PRESS F1 TO CONTINUE"
20 GETAS
30 (FA$OCHR$(133)THEN20
40 ? "YOU HAVE PRESSED F1"
172
USING C64 MODE—Using the Keyboard in C64 Mode