PA-7300LC (PCX-L2) processor
The PA-7300LC is an integrated,
low-cost PA-RISC 32-bit processor, released in mid-1996.
While being a close successor to the earlier PA-7100LC,
it has several enhancements:
- Large on-chip L1 caches, in contrast to the small
assistcaches of the PA-7100LC and PA-7200.
- Integrated L2 cache controller in the MIOC.
- Improved bus interface with faster GSC bus variant.
- Faster memory interface.
The then current process technologies made it possible to include a large L1 cache on the CPU die, breaking a long-standing HP tradition of large off-chip L1 caches. The PA-7300LC was the final 32-bit, PA-RISC version 1.1 CPU, later workstations and servers used 64-bit PA-RISC 2.0 processors, such as the PA-8000, being introduced in the same timeframe.
- PA-RISC version 1.1e 32-bit
- Three functional units: 2 integer ALUs, 1 Floating Point unit
- 2-way superscalar
- MAX-1 multimedia extensions for multimedia applications
- 64 KB/64 KB I/D on-chip L1 caches, each two-way set associative, virtually indexed
- Cache line size of 32 Byte
- Caches have a 64-bit datapath to the execution units, 256-bit datapath to main memory
- Optional unified I/D L2 off-chip cache, up to 8192 KB
- No hashing for both I and D caches
- L2 cache is write-through, direct mapped, physically indexed and physically tagged
- Instruction prefetch buffer moved from memory controller to L1 instruction cache, thus allowing prefetch hits without penalty
- On-chip MIOC memory controller
- 96-entry unified I/D TLB
- 8-entry BTLB
- 4-entry ILAB
- GSC system interface implements GSC+ features, maximum clock frequency of 40 MHz — actual system implement from 33 MHz and 132 MB/s up to 40 MHz and 160 MB/s
- Either 64-bit or 128-bit datapath from execution units to the memory
- Up to 180 MHz frequency with 3.3 V core voltage
- 15.3×17.0 mm2 die, 9,200,000 FETs, 0.5µ, 4-layer metal CMOS14C process in a 464-pin ceramic PGA package
Only one of the two integer ALUs is able to handle loads, stores and shifts, these operations can only be paired with simple math operations, like integer addition o multiplication. Both units can handle branch operations.
- HP 9000 744, 745, 748 VME workstations
- HP 9000 A180, A180C servers
- HP 9000 B132L, B132L+, B160L, B180L+ workstations
- HP 9000 C132L, C160L workstations
- HP 9000 D220, D230, D320, D330 servers
- RDI PrecisionBook laptop
- Hitachi 3050RX 255, 355E, 365 workstations
- HP Agilent 16600A, 16700A, 16700B, 16702A and 16702B series logic analyzers
- PA7300LC ERS (External Reference Specification) (PDF, 716 KB) Hewlett-Packard Company (1996)
The PA-7300LC: the first
System on a Chip(archive.org mirror) Tom Meyer (1996: Presentation for Microprocessor Forum 1995)
- The PA 7300LC Microprocessor: A Highly Integrated System on a Chip (PDF, 50 KB) Terry W. Blanchard and Paul G. Tobin (June 1997: Hewlett-Packard Journal)