AXPvme Single-Board Computer

This document, the "AXPvme Single-Board Computer Release Notes," outlines several important issues and recommendations for the AXPvme single-board computers.

Key points include:

• VIC64 Write Posting: Users should NOT enable Write Posting in the VIC64 to prevent potential deadlocks and system hangs caused by cycle collisions.
• Front Panel Installation: To avoid damage, captive screws on AXPvme modules must be fully retracted before attempting final seating during installation.
• D64 Usage: Two critical situations exist with D64 transfers: illegal memory access operations (e.g., writing to nonexistent or protected memory) can cause system crashes, and D64 transfers can return incorrect VME vectors if the AXPvme is a VME interrupter. These conditions are expected to be corrected in the future.
• AXPvme 64LC Firmware: On the AXPvme 64LC model (without external backup cache or SCSI), bad memory modules are not properly detected during the initial startup phase, though they still prevent console startup.
• -12 V Power: The AXPvme requires a maximum of 100 mA at -12 V, used exclusively for the console and auxiliary serial-line drivers.
• PCI Mezzanine Card Keepout: AXPvme modules are not fully compliant with the PCI Mezzanine Card Standard, featuring an 18.5 mm keepout area instead of the specified 30.5 mm. Compatible PCI Mezzanine cards must adhere to the 18.5 mm restriction.
• SCSI Cables: Recommendations are provided for properly terminated 50-pin IDC SCSI cables for connecting local disks, including specific Digital part numbers for various lengths and connector configurations for internal and external drives.