Model 466-1 Adapter
Common Problems And Solutions 77
9.5 Using The VMEbus Adapter Card LEDs As Diagnostic Tools
Use the REMOTE and LOCAL LEDs in conjunction with the Remote and
Local Status Registers to track down the cause of a problem.
READY
: Immediately after power-up, the
READY
LED should be
illuminated indicating that the on-board programmable gate arrays have
been successfully loaded. If this LED is not lit, any access to the adapter
card will result in an interface time out or BERR. If the VMEbus adapter
card is system controller, accesses by a VMEbus CPU will "hang" the
VMEbus system and will require a system reset or power cycle to recover.
If the
READY
LED is not lit, it could be caused by a VMEbus power
supply that may be slow ramping, or does not have a uniform voltage
ramp-up.
REMOTE:
When the VMEbus adapter card is processing a command
from the SBus adapter card, the
REMOTE
LED on the VMEbus adapter
card will be illuminated. After the command is processed, the LED will
switch off. Therefore, for a single read or write, the length of time the
LED will be lit is too short to perceive with the naked eye. If the SBus
system is placed in a software loop to repeatedly access the VMEbus
adapter card, the LED will appear to be lit continuously. Varying degrees
of brightness indicate a corresponding amount of activity.
If the
Remote
LED is always on, an operation across the cable did not
complete normally. This may be caused by the VMEbus adapter card not
gaining VMEbus mastership. See also section 9.2.3.
LOCAL:
When a CPU in the local VMEbus chassis accesses the
VMEbus adapter card, the
LOCAL
LED is illuminated. This LED
remains lit as long as the address being generated is recognized by either
the adapter's Dual Port window or the I/O Register window. This LED
may be lit even though there is no VMEbus activity because the CPU
continues to drive the VMEbus address lines after the cycle has
completed. When a bus cycle to a different device takes place, the
LOCAL
LED will switch off.
Summary of Contents for 466-1
Page 1: ...Model 466 1 Adapter Hardware Manual Connects a SBus Computer to a VMEbus System...
Page 2: ...Model 466 1 Adapter ii...
Page 24: ...Model 466 1 Adapter 14 Adapter Functions...
Page 52: ...Model 466 1 Adapter 42 VMEbus Adapter Card Configuration...
Page 70: ...Model 466 1 Adapter 60 CSR Accessed From The SBus...
Page 88: ...Model 466 1 Adapter 78 Common Problems And Solutions...
Page 106: ...Model 466 1 Adapter 96 Jumper Configuration Worksheets...
Page 107: ...Model 466 1 Adapter Jumper Configuration Worksheets 97 D 1 SBus Adapter Card Worksheet J1...
Page 108: ...Model 466 1 Adapter 98 Jumper Configuration Worksheets...
Page 110: ...Model 466 1 Adapter 100 Jumper Configuration Worksheets...
