VB: I/O HARDWARE INTERFACING

a Microsoft Visual Basic 6.0 program for input-output hardware interfacing in DB25

► reference:
lvr.com
logix4u.net


► DB25 pin configuration (computer side)
...........\ o o o o o o o o o o o o o /
............\ o o o o o o o o o o o o /

s4 s5 s'7 s6 d7 d6 d5 d4 d3 d2 d1 d0 c'0
GND GND GND GND GND GND GND GND c'3 c2 s3 c'1

► pins

data (d)
- address: 378
- input and output

control (c) pins
- address: 37A
- output only

status (s)
- address: 379
- input only

ground (GND) = n/a
- ground

► usage:

- data
output:
x = woutput Val(&H378), n
input:
x = woutput Val(&H37A), 32
y = winput(&H378)

- status
x = winput(&H379)

- control
x = out (37A,n)

► note:
if a pin has an apostrophe, it means that it will transmit a reverse output or receive a reverse input

► steps:
1. create the hardware

2. download the inpout32.dll file

3. create a inpout32.bas file

Attribute VB_Name = "inpout"

Public Declare Function winput Lib "inpout32.dll" _
Alias "Inp32" (ByVal PortAddress As Integer) As Integer

Public Declare Sub woutput Lib "inpout32.dll" _
Alias "Out32" (ByVal PortAddress As Integer, ByVal Value As Integer)

4. place the inpout32.dll and the inpout32.bas file inside the project folder

5. create the code


► sample code:

Option Explicit
Dim readdata As Integer
Dim readstatus As Integer
Dim ndata As Integer
Dim ncontrol As Integer

Private Sub cmdreaddata_Click()
woutput Val(&H37A), 32
readdata = winput(&H378)
lblreaddata.Caption = readdata
End Sub

Private Sub cmdwritedata_Click()
ndata = Val(txtwritedata.Text)
woutput Val(&H378), ndata
End Sub

Private Sub cmdreadstatus_Click()
readstatus = winput(&H379)
lblreadstatus.Caption = readstatus
End Sub

Private Sub cmdwitecontrol_Click()
ncontrol = Val(txtwritedata.Text)
woutput Val(&H37A), ncontrol
End Sub