Motorola MVME2300 Series - Manual (Page 66)

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Board Description and Memory Maps
1
Semaphore Register 1
Semaphore Register 1 is an 8-bit register located at ISA I/O address x1004.
The Universe ASIC is programmed so that this register can be accessible
from the VMEbus. This register can only be updated if bit 7 is low or if the
new value has the most significant bit cleared. When bit 7 is high, this
register will not latch in the new value if the new value has the most
significant bit set.
Semaphore Register 2
Semaphore Register 2 is an 8-bit register located at ISA I/O address x1005.
The Universe ASIC is programmed so that this register can be accessible
from the VMEbus. This register can only be updated if bit 7 is low or if the
new value has the most significant bit cleared. When bit 7 is high, this
register will not latch in the new value if the new value has the most
significant bit set.
REG Semaphore Register 1 - Offset $1004
BIT SD7 SD6 SD5 SD4 SD3 SD2 SD1 SD0
FIELD SEM1
OPER R/W
RESET 0 0 0 0 0 0 0 0
REG Semaphore Register 2 - Offset $1005
BIT SD7 SD6 SD5 SD4 SD3 SD2 SD1 SD0
FIELD SEM2
OPER R/W
RESET 0 0 0 0 0 0 0 0