SBS Technologies 466-1, Hardware Manual

Page: 31 / 110

Model 466-1 Adapter
SBus Adapter Card Configuration 21
3.5.1 D16/D32 Data Transfer Size Jumper (Jumper 1)
Jumper 1 configures the SBus adapter card to correspond to the data transfer
size used by the VMEbus adapter card. The VMEbus adapter card supports a
32-bit data transfer size; consequently,
Jumper 1 should not be installed (no
modification to factory setting required).
3.5.2 Address Map Disable Jumper (Jumper 2)
Installing Jumper 2 disables remote bus access to control SPARCstation
access to VMEbus resources. Areas that can be disabled are VMEbus
decodings, including VMEbus RAM and VMEbus I/O.
Example: An application that allows the SBus system to access only remote
Dual Port RAM and that should never access the VMEbus
backplane (remote bus), benefits by using
Jumper 2 to disable
access to the VMEbus. If Jumper 2 is installed, an inadvertent
attempt by the SBus to access the VMEbus results in a SBus
timeout. Consequently, isolation is ensured.
After an address map area is disabled, it no longer exists for the SBus
adapter card. Any access to that area results in a SBus timeout and
requires an error handler routine to recover.
3.5.3 Remote Address A24/A32 Select Jumper (Jumper 3)
This feature is supported only on Model 466-1 adapters with the SBS
SBus adapter card Part Number 84202322. The part number is identified
on the card's SBus connector.
Jumper 3 determines the address modifier code to be sent to the VMEbus
when the remote A24/A32 RAM window is selected. The remote A24/A32
RAM window is defined in section 3.3.
If VMEbus A32 space is to be addressed, Jumper 3 should not be installed.
Otherwise, Jumper 3 should be installed.