PXS20RM Datasheet, PDF (1286/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Semaphore Unit (SEMA4)
Table 43-1. SEMA4 memory map (continued)
Address offset
Register
0x000D
SEMA4_Gate13—Semaphores gate 13
0x000E
SEMA4_Gate14—Semaphores gate 14
0x000F
SEMA4_Gate15—Semaphores gate 15
0x0010–0x003F Reserved
00x040
SEMA4_CP0INE—Semaphores CP0 IRQ notification enable
0x0042–0x0047 Reserved
0x0048
SEMA4_CP1INE—Semaphores CP1 IRQ notification enable
0x004A–0x07F Reserved
0x0080
SEMA4_CP0NTF—Semaphores CP0 IRQ notification
0x008 2–00x087 Reserved
0x0088
SEMA4_CP1NTF—Semaphores CP1 IRQ notification
0x008A–0x00FF Reserved
0x0100
SEMA4_RSTGT—Semaphores reset gate
0x0102
Reserved
0x0104
SEMA4_RSTNTF—Semaphores reset IRQ notification
0x0106–0x3FFF Reserved
Location
on page 43-4
on page 43-4
on page 43-4
on page 43-5
on page 43-5
on page 43-5
on page 43-5
on page 43-6
on page 43-8
43.3.1 Semaphores gate n register (SEMA4_GATEn)
Each semaphore gate is implemented in a 2-bit finite state machine, right-justified in a byte data structure.
The hardware uses the bus master number in conjunction with the data patterns to validate all attempted
write operations. Only processor bus masters can modify the gate registers. After it is locked, a gate must
be opened (unlocked) by the locking processor core.
Multiple gate values can be read in a single access, but only a single gate at a time can be updated via a
write operation. 16- and 32-bit writes to multiple gates are allowed, but the write data operand must update
the state of a single gate only. A byte write data value of 0x03 is defined as no operation and does not affect
the state of the corresponding gate register. Attempts to write multiple gates in a single-aligned access with
a size larger than an 8-bit (byte) reference generate an error termination and do not allow any gate state
changes.
Offset: n (n = 0x0, 0x1,0x2,..., 0xF)
Access: User read/write
0
1
2
3
4
5
6
7
R
0
0
0
0
0
0
W
GTFSM
Reset
0
0
0
0
0
0
0
0
Figure 43-2. SEMA4 gate n register (SEMA4_GATEn)
43-4
PXS20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor