Themis TA64, Руководство по оборудованию

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4-6
Themis Computer
TA64 Hardware Manual
When the Universe II is configured as the System Controller, it provides the follow-
ing functions on the VMEbus:
— A 16MHz Clock Driver
— An Arbitration Module
— A bus timer
— An IACK Daisy Chain Driver (DCD).
The TA64 supports Round-Robin arbitration. The VMEbus arbitrator time out is also
controlled by the MISC_CNT register described above. The timer may be set to
either 16
μ
s
, 256
μ
s
, or disabled. The default setting is 16
μ
s
. The arbitration timer
has a granularity of 8
μ
s
; setting the timer to 16
μ
s
means the timer may expire in as
little as 8
μ
s
or as much as 24
μ
s
. It should also be noted that disabling the arbitration
timer implies that the Universe II will not recover from an access error. Disabling the
arbitration timer is not recommended.
4.2.4.1 Automatic Slot Identification
The Universe II supports two types of Auto ID functionality:
• Auto Slot ID as described by the VME64 specification
• Proprietary Method which is developed by Tundra
Refer to “Auto Slot ID: VME64 Specified”, page 2-24, and “Auto-ID: A Proprietary
Tundra Method”, on page 2-25 of the Universe II Manual for more information.
17 SYSCON
SYSCON:
0 = Universe II is not a VMEbus System Controller;
1 = Universe II is a VMEbus System Contoller
Power-up
Option
R/W
16 V64AUTO
VME64 Auto ID:
Write: 0 = no effect; 1 = Initiate sequence
This bit initiates the Universe II VME64 Auto ID Slave
participation.
Power-up
Option
R/W
a—All unspecified bits in this table are RESERVED for the Universe II. Reading the bits results in an undefined state; writing to
these bits should be 0.
Table 4-1. Universe II Miscellaneous Control Register (MISC_CTL)
a
(Continued)
BIts Name Description
Reset
State
Access