Semaphores
PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor 15-3
if gate = 0b01, then state = locked by e200z6 (master ID = 0)
if gate = 0b10, then state = locked by e200z0 (master ID = 1)
– Uses the bus master ID number as a reference attribute plus the specified data patterns to
validate all write operations
– After it is locked, the gate must be unlocked by a write of zeroes from the locking processor
— Optionally enabled interrupt notification after a failed lock write provides a mechanism to
indicate the gate is unlocked
— Secure reset mechanisms are supported to clear the contents of individual semaphore gates or
notification logic, and clear_all capability
NOTE
Semaphore gates that are locked when entering sleep mode are cleared by
the internal reset generated when exiting sleep mode.
15.1.3 Modes of Operation
The semaphores module does not support any special modes of operation.
15.2 Signal Description
The semaphores module does not include any external signals.
15.3 Memory Map and Registers
This section provides a detailed description of all semaphores registers.
15.3.1 Module Memory Map
The semaphores programming model map is shown in Table 15-1. The address of each register is given as
an offset to the semaphore base address. Registers are listed in address order, identified by complete name
and mnemonic, and list the type of accesses allowed.
Table 15-1. Semaphores Memory Map
Offset from
SEMA4_BASE
(0xFFF1_0000)
Register Access Reset Value
Section/
Page
0x0000 SEMA4_Gate00—Semaphores gate 0 R/W 0x00 15.3.2.1/15-4
0x0001 SEMA4_Gate01—Semaphores gate 1 R/W 0x00 15.3.2.1/15-4
0x0002 SEMA4_Gate02—Semaphores gate 2 R/W 0x00 15.3.2.1/15-4
0x0003 SEMA4_Gate03—Semaphores gate 3 R/W 0x00 15.3.2.1/15-4
0x0004 SEMA4_Gate04—Semaphores gate 4 R/W 0x00 15.3.2.1/15-4
0x0005 SEMA4_Gate05—Semaphores gate 5 R/W 0x00 15.3.2.1/15-4
0x0006 SEMA4_Gate06—Semaphores gate 6 R/W 0x00 15.3.2.1/15-4
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