User guide

10.3.3.2 VMEbus Transfer Timers
When enabled, the VME interface starts the transfer timer whenever the data
phase of a cycle is signaled (DSx* asserting). If the timer expires before the data
cycle is acknowledged or completes in error, the VME interface, as the system
controller, flags a VMEbus error (asserting BERR*). This condition sets a status
bit in the VMEbus error status register (VIC_BESR).
The transfer timeout is configured in the VMEbus transfer timeout register (VIC_
TTR, offset 0xA0), shown in Figure 10–13.
Figure 10–13 VMEbus Transfer Timeout Register
31 07 05 04 02 01 00
ML013344
VMEbus Timeout
Local bus Timeout
Don't Care
VME_IF_BASE+A0 :
Arb. Timeout Status
Include VME Time Acquisition
VIC_TTR
08
Table 10–9 VMEbus Transfer Timeout Register
Field Name Description
<0> When set, the local bus timer includes the time for VMEbus
acquisition
<1> Arbitration
timeout status
This bit is set when the arbitration timer expires.
<4:2> Local bus
timeout
Specifies the timeout, according to the following values:
000 4 microseconds
001 16 microseconds
010 32 microseconds
011 128 microseconds
100 256 microseconds
101 512 microseconds
111 Disabled
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10–22 VME Interface