CHAPTER 7 PCI CONTROLLER
408 Preliminary User’s Manual S15543EJ1V0UM
7.5.19.14 Subsystem ID register
This register is used to uniquely identify the expansion board or subsystem where the PCI device resides.
R/WBits Field
Internal
bus
PCI
Default Description
15:0 Subsystem ID R/W R 0 The VR4120A should set the identifier to this register.
7.5.19.15 Cap_Ptr register
This register is used to show a linked list of new capabilities implemented by The PCI Controller. The PCI
Controller has PPMI function as a new capability. Its data structure starts from ‘40H’ in the configuration register.
R/WBits Field
Internal
bus
PCI
Default Description
7:0 Capabilities
Pointer
R R 40H Hardwired to ‘40H’, where is the first term of the new capabilities
list.
7.5.19.16 Interrupt line register
The Interrupt Line register is used to communicate interrupt line routing information.
R/WBits Field
Internal
bus
PCI
Default Description
7:0 Interrupt Line R/W R/W 0 The value in this register shows the input of the system interrupt
controller that the interrupt pin is connected.
7.5.19.17 Interrupt pin register
This register tells which interrupt pin the PCI Controller uses.
R/WBits Field
Internal
bus
PCI
Default Description
7:0 Interrupt Pin R R 01H Hardwired to ‘01H’, which means the PCI Controller uses INTA_B
pin.
7.5.19.18 Min_Gnt register
This register specifies how long a burst period the PCI Controller needs assuming a clock rate of 33MHz.
R/WBits Field
Internal
bus
PCI
Default Description
7:0 Min_Gnt R/W R 0 The user of the PCI Controller must prepare the value to this
register. The value should be set by the VR4120A.