1.3.3 Ultra2 SCSI Technology
The SYM8953U fully supports Ultra2 SCSI. Ultra2 SCSI is an extension of the SCSI Parallel Interface 2 and 3
For the internal bus, special impedance SCSI ribbon cables are specified for operation with Ultra and Ultra2 SCSI devices. You must consider the total length of the bus cables and the number of devices on the SCSI bus when setting up your system. Make sure that your SCSI cables are rated for standard SCSI (Fast, Ultra, and Ultra2) environments. Chapter 2, “Installing the SYM8953U Host Adapter”has a detailed explanation of SCSI bus connections.
1.3.4 LVD Link Technology
To support greater device connectivity and a longer SCSI cable, the SYM8953U features LVD Link technology, the LSI Logic implementation of Universal LVD SCSI. LVD Link transceivers provide the inherent reliability of differential SCSI, and a
The LVD Link transceivers reduce the power needed to drive the SCSI bus, so that the I/O drivers can be integrated directly into the chip. LVD Link technology lowers the amplitude of noise reflections and allows higher transmission frequencies.
The LVD Link transceivers operate in LVD and SE modes. They also allow the chip to detect a High Voltage Differential (HVD) signal when the chip is mistakenly connected to external HVD transceivers. When connected, the SYM53C895A chip automatically detects signal type, based on the voltage detected. It automatically switches to the SE or LVD mode, as appropriate. All bus devices must be LVD or SE. If a HVD device is detected, the board puts the SCSI bus in the high impedance state and shuts down.
1.3.4.1 Benefits of LVD Link
LVD Link, supported by the SYM53C895A, is a signaling technology that increases the reliability of SCSI data transfers over longer distances than supported by SE SCSI. The low current requirements of LVD allow direct
Interface Descriptions |
