Hardware Level Communications For Pci - Galil Motion Control DMC-18 2 Series User Manual

Servicing Interrupts
Once an interrupt occurs, the host computer sends an associated Status Byte along with the interrupt
vector. The Status Byte returned denotes what condition has occurred, as described in the table below.
Status Byte (hex)
00
D9
DA
DB
F0 thru FF
E1 thru E8
C0
C8
D8
D7
D6
D5
D4
D3
D2
D1
D0
The recommended method to utilize the interrupts in a host application is to use a pre-defined interrupt
service routine. Where the event routine, on interrupt, will automatically execute and return the Status
Byte. For example, when using the ActiveX toolkit DMCShell control with VB, the
DMCShell1_DMCInterrupt() event procedure (shown below) will automatically execute and return the
StatusByte in the argument. This StausByte can then be used in a case structure as the key to notify the
host application of a specific event or condition.
In this VB example below, the event procedure will display a message box every time the X-axis
motion is complete, assuming the command EI1 was sent to the controller. Note: the argument is
returned as 208 since the status byte is returned as an integer (i.e. D0 hex = 208 decimal).
Private Sub DMCShell1_DMCInterrupt(StatusByte As Integer)
End Sub

Hardware Level Communications for PCI

This section of the chapter describes in detail the structures used to communicate with the DMC-18x2
controller at the register interface level. The information in this section is intended for advanced
programmers with extensive knowledge of PCI bus operation.
DMC-18x2
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Condition
No interrupt
Watchdog timer activated
Command done
Application program done
User interrupt
Input interrupt
Limit switch occurred
Excess position error
All axis motion complete
H axis motion complete
G axis motion complete
F axis motion complete
E axis motion complete
W axis motion complete
Z axis motion complete
Y axis motion complete
X axis motion complete
If StatusByte = 208 Then
MsgBox "X axis complete"
End If
Chapter 4 - Software Tools and Communications • 53