Chapter 4 PA-RISC Computer Systems - OpenPA.net

PA-RISC SCSI SCSI chipsets
� J200, J210, J210XC, J280, J282
� K-Class
� RDI PrecisionBook 132, 160, 180
� R380, R390
� SAIC Galaxy 1100
53C720
The NCR 53C720 was the secondary SCSI controller used in the early HP 9000s for the attachment
of an Fast-Wide (16-bit) SCSI-2 bus, utilizing HVD signalling. It was either controlled by the ASP2
chipset or interfaced to the GSC bus through a chip named Zalon.
Features
� One Fast-Wide SCSI channel
� Chip support for SE and HVD transfer modes (in the HP 9000s only HVD logic is used)
� Synchronous SCSI transfer rate of 20 MB/s
� Asynchronous SCSI transfer rate of 10 MB/s
� 64-Byte DMA FIFO
� 16- or 32-bit bus master DMA device
� Attaches to host bus interface, can either be Motorola 68030 (bus up to 25 MHz async) or 68040
(bus up to 33 MHz sync) or Intel 80386SX or 80386DX compatible
� Support both big or little endian
� Sustained host bus bandwitdh of more than 100 MB/s
� 208-pin QFP package
Used in
� 735, 755 (ASP2)
� B132L, B160L
� C100, C110, C132L, C160L, C160, C180
� D-Class
� J200, J210, J210XC, J280, J282
� K-Class
� R380, R390
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