Siemens PANEL PC 877 User Manual

Page of 288
Detailed descriptions 
 
17.2 Bus board 
 
SIMATIC Panel PC 877 
17-26
 
Operating instructions, Release 07/2006, A5E00877780-01 
17.2.3 
Exclusive PCI hardware interrupt 
Applications demanding a high-performance interrupt require a high-speed hardware 
interrupt reaction. The PCI hardware interrupt should be used only by one resource in order 
to ensure high-speed reaction of the hardware. This can be forced by appropriate setting in 
the system BIOS.  
Setting up a reserved interrupt on the device  
A reserved interrupt can only be set and used for PCI slots 2 and 4. Further reserved 
interrupts for use on the slots are not available. 
A reserved interrupt cannot be used on any of the PCI slots in the basic configuration. In 
order to set up a reserved interrupt, you first need to disable the functions on the 
motherboard
1)
. This is possible for PCI slots 2 and 4. 
In order to set up a reserved interrupt on PCI slot 2, you need to disable USB Controller B 
(this is the external USB port at the top) in the BIOS.  
In order to set up a reserved interrupt on PCI slot 4, you need to disable USB 2.0 Controller 
in the BIOS (all USB ports are now operating in USB 1.1 mode) and (if installed in the 
device) the PROFIBUS. 
1) 
For information on how to disable motherboard functions, refer to the chapter dealing with 
the BIOS setup. 
Assigning a reserved interrupt in the BIOS Setup 
With the factory setting of the system BIOS, the interrupts are automatically assigned to the 
slots. 
Depending on the system configuration, several slots may be assigned the same interrupt. 
Here we refer to interrupt sharing. 
The special feature of the BIOS of the device is that interrupts can be set selectively and 
assigned to the interrupt channels of the slots. Here we refer to a reserved interrupt. 
Specific interrupts can be assigned to slots in the  Advanced menu of the BIOS setup. 
To do so: 
To enable the use of a reserved interrupt at PCI slot 2, assign PCI IRQ Line 2 the required 
free interrupt, and all other PCI interrupt channels (channels 1, 3, 4) another interrupt.  
To enable the use of a reserved interrupt at PCI slot 4, assign PCI IRQ Line 4 the required 
free interrupt, and all other PCI interrupt channels (channels 1, 2, 3) another interrupt. 
To do this, open the Advanced menu of the BIOS setup and then  PCI Configuration. In this 
menu you can assign the specific PCI IRQ channels to the respective interrupts. 
You cannot assign interrupts that are already used by the system.  
If you assign an interrupt which is already in use by the system or is reserved, the system 
marks it with a yellow star.  
➜ May not be used.  
Interrupts not reserved by the system can be assigned twice.