Themis USPIIi-1v, Hardware Manual

Page: 45 / 128

Themis Computer
5-5
5. Universe-IIB Description
When the Universe IIB is configured as the System Controller, it provides the following functions on the
VMEbus:
– A 16MHz Clock Driver
– An Arbitration Module
– A bus timer
– An IACK Daisy Chain Driver (DCD).
The USPIIi-1v 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 IIB will not recover from an access error. Disabling the arbitration timer is not
recommended.
5.3.4.1 Automatic Slot Identification
The Universe IIB supports two types of Auto ID functionality:
• Auto Slot ID as described by the VME64 specification
• Proprietary Method which is developed by Tundra
[25:24] VARBTO VMEbus Arbitration Time-out
00 = Disable Timer; 01 = 16
µ
s (minimum value of 8
µ
s,
due to the 8
µ
s clock granularity); 10 = 256
µ
s;
others - RESERVED
01 R/W
23 SW_LST PCI Reset: 0 = no effect; 1 = initiate PCI bus LRST# 0 W
22 SW_SYSRST Software VMEbus SYSRESET: 0 = no effect; 1 = Initiate
VMEbus SYSRST 0 W
20 BI BI- Mode: 0 = Universe IIB is in BI-mode;
1 = Universe IIB is not in BI mode Power-up
Option R/W
19 ENGBI Enable Global BI-mode Initiator:
0 = Assertion of VIRQ1 ignored; 1 = Assertion of VIRQ1
puts the Universe IIB in BI-mode 0 R/W
18 RESCIND Unused on the Universe IIB 1 R/W
17 SYSCON SYSCON:
0 = Universe IIB is not a VMEbus System Controller;
1 = Universe IIB 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 IIB VME64 Auto ID Slave par-
ticipation. Power-up
Option R/W
a. All unspecified bits in this table are RESERVED for the Universe IIB and should not be accessed by the user.
Table 5-2. Universe IIB Miscellaneous Control Register (MISC_CTL)
a
BIts Name Description Reset
State
Access