12. Register Descriptions
351
PowerSpan II User Manual
80A1010_MA001_09
Integrated Device Technology
www.idt.com
12.5.61
Semaphore 1 Register
If a SEMx is 0, this semaphore can be obtained by writing a 1 to the SEMx bit with a unique tag TAGx.
If on a subsequent read, the SEMx bit is set and the TAGx field contains the same unique tag, then the
semaphore has been obtained successfully.
To release a semaphore, write a 0 to the SEMx bit and the same tag that was used to obtain the
semaphore. If the tag is different from the tag that is in the register, then the write will have no effect.
Access to a single semaphore in this register requires a byte-wide transaction.
Register Name: SEMA1
Register Offset: 0x474
PCI
Bits
Function
PB
Bits
31-24
SEM7
TAG7
0-7
23-16
SEM6
TAG6
8-15
15-08
SEM5
TAG5
16-23
07-00
SEM4
TAG4
24-31
Name
Type
Reset
By
Reset
State
Function
SEM7
R/W
G_RST
0
Semaphore 7
TAG7[6:0]
R/W
G_RST
0
Tag 7
SEM6
R/W
G_RST
0
Semaphore 6
TAG6[6:0]
R/W
G_RST
0
Tag 6
SEM5
R/W
G_RST
0
Semaphore 5
TAG5[6:0]
R/W
G_RST
0
Tag 5
SEM4
R/W
G_RST
0
Semaphore 4
TAG4[6:0]
R/W
G_RST
0
Tag 4