1

Board Description and Memory Maps

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.

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

 

 

 

 

 

 

 

 

 

 

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 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

 

 

 

 

 

 

 

 

 

 

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Computer Group Literature Center Web Site

Page 66
Image 66
Motorola MVME2300 Series manual Semaphore Register 1 Offset $1004, SEM1, Semaphore Register 2 Offset $1005, SEM2