hp workstations zx6000, hp server rx2600 - operation and maintenance guide

System Board
System Board Components
Appendix B
184
I/O Bus Interface
The I/O bus interface provides these features:
• Provides industry standard AGP 1× and 2× support for legacy graphics, and AGP 4×
for current high performance graphics.
• Provides features to enable use in HP-UX systems.
• Provides a 64-bit data width.
• Uses 3.3V PCI only, and it does not support 5V PCI.
• Optimizes for DMA performance.
• Supports AGP fast writes (only to addresses less than 4GB).
• Uses peer-to-peer (P2P) subset that is required by the AGP specification (write-only,
PCI cycles).
• Supports up to six PCI slots and 10 wire interrupts.
Processor Dependent Hardware Controller
The processor dependent hardware controller (PDH) provides these features:
• Simple seven-bit, point-to-point bus interface
• 16-bit PDH bus with reserved address space for:
— Flash memory
— Non-volatile memory
— Scratch RAM
— Real Time Clock
— UARTs
— External Registers
— Firmware read/writable registers
— Two general purpose 32-bit registers
— Semaphore registers
— Monarch selection registers
— Test and Reset register
• Reset and INIT generation