PA-RISC Chipsets
zx1 chipset
The zx1 chipset was a HP Itanium chipset bus used in later HP 9000 and Integrity PA-RISC servers as well. It consists of two purpose-built main parts that connect the processor, memory and I/O to the Itanium system main buses: Pluto and Mercury.
- Pluto zx1 memory and I/O controller (MIO) is the main chipset controller
- Processor bus
- Two independent memory buses
- I/O channels (I/O ropes)
- Mercury zx1 I/O adapters IOAs connect PCI-X/AGP slots and I/O devices to Pluto
The rest of the I/O chipset is made up of standard third-party, such as SCSI controllers, Ethernet.
Pluto
Many of the Itanium-based HP workstations and servers use the Pluto I/O and memory controller as part of the zx1 chipset. Pluto is based on the Astro IOMMU, extending it for Itanium-2 processors and bus interfaces, DDR memory and faster I/O links.
- Processor bus: Itanium-2 processor bus for up to four CPUs, maximum of 200 MHz bus with 128-bits for up to 6.4 GB/s data rate.
- Two memory buses with peak 8.0 GB/s at maximum clock of 266 MHz DDR.
- I/O system based on eight separate 500 MB/s I/O links for individual PCI, PCI-X or AGP bridges. Peak aggregate I/O bandwidth is 3.2 GB/s
- Support for DDR SDRAMs
- Maximum supported memory of 16 GB to 64 GB with SME memory extender
- 16-entry I/O TLB
- 16-entry coherent I/O cache
Mercury
Mercury is a PCI/AGP bridge for systems based on I/O ropes. It is part of the zx1 chipset used on Itanium systems (alled zx1 I/O adapter, and based on the Elroy PCI bridge, extending it for AGP devices and faster I/O ropes. Most systems use several Mercury chips to attach PCI/AGP buses to the multiple I/O ropes. Each Mercury attaches one PCI or AGP bus to up to four 500 MB/s I/O ropes.
Mercury is most often used together with the Pluto I/O and memory controller of the zx1 chipset.
- Attaches to one to four (bundled) I/O ropes
- Provides one PCI, PCI-X or AGP 2.0 bus
- Multiple Mercurys can be used in a single system
- Support for PCI 2.1, also some support for PCI 2.2
- Support for PCI-X
- Support for AGP 1X, 4X and 4X
- PCI data width of 32 or 64 bit
- PCI clock of 33 or 66 MHz
- PCI-X clock of up to 133 MHz
- Up to six PCI slots
- No support for 5 V PCI
Used in
- rp3410, rp3440, rp4410, rp4440, rp7420
- rx1600, rx1620, rx2600, rx2620, rx2660 rx3600, rx5670, rx6600, rx7620, rx7640, rx8620, rx8640
- Superdome
- zx2000, zx6000
References
- zx1 mio (Memory and I/O) External Reference Specification Hewlett-Packard Company (March 2003, Revision 1.0)
- HP zx1 ioa ERS External Reference Specification Ropes to AGP/PCI/PCI-X Bridge (.pdf) Hewlett-Packard Company (April 2003, Revision 3.2)