Manual Number: 00650-014-4
Page 2-6
AD12-8 Manual
OutPort
Function:
Writes all 16 bits of
value
to the hardware port at
address
. This function
returns the value output.
Declaration:
function OutPort(byval
address as integer, byval value as
integer) as integer
Peek
Function:
Reads a byte from main memory (DRAM).
Declaration:
function Peek(byval segment as integer, byval offset as integer)
as integer
Poke
Function:
Writes the lower eight bits of
value
to
segment
:
offset.
Declaration:
function Poke(byval segment as integer, byval offset as integer,
byval value as integer) as integer
Note that in all of the above functions, an inherent limitation of BASIC in general and VisualBASIC
in particular makes the values sent less intuitive. All integers in BASIC are signed numbers,
wherein data are stored in twos complement form. All bit patterns must be converted to-and-from
this twos complement form if meaningful display is required. Otherwise, values returned from the
InPortb function will be -128 to 127, rather than 0 to 255. An alternative is to perform all assign-
ments in hexadecimal, rather then decimal form.
Before the program will execute, the .GBL file must be modified to include the path to the
VBACCES.DLL as appropriate for your system. Merely replace the statement VBACCES.DLL
with
drive:path
\VBACCES.DLL.
As an alternative to changing the source code, you can copy the VBACCES.DLL file into your
Windows directory. This will allow multiple programs to find the same .DLL without having to
know where it is located. Just leave off all references to a path in the .GBL file as shown in the
sample.
