Switch S4 is similar in function to the general-purpose readable jumper headers found on earlier MVME162/172 series boards. S4 provides eight software-readable switch segments.
These switches can be read as bits in a register (at address $FFF4202C) in the MC2 General-Purpose Inputs register in the Petra ASIC (refer to the Programmer’s Reference Guide for details).
Bit GPI7 is associated with switch segment 1; bit GPI0 is associated with switch segment 8. The bit values are read as a 0 when the switch is on, and as a 1 when the switch is off. The MVME162P4 is shipped from the factory with S4 set to all 0s (all switches set to ON), as diagrammed below.
If the MVME162Bug firmware is installed, four bits are user-definable (i.e., switch segments 1-4). If the MVME162Bug firmware is not installed, seven bits are user-definable (i.e., segments 1-4 and segments 6-8).
Note: Switch segment 5 (GPI3) is reserved to select either the Flash memory map (switch set to ON) or the EPROM memory map (switch set to OFF). GPI3 is not user-definable.
Note: Model Number: MVME162P-344SE, Characteristics: 32MHz 68040, 16MB SDRAM, 2 SIO, 4 DMA IP, SCSI/Ethernet is used on Universal UIC HSP4797L Hitachi Sanyo TCM-X100 P.C.B. Mount 6300901030