CSM9S12XDT512SLK Freescale Semiconductor, CSM9S12XDT512SLK Datasheet - Page 204

Manufacturer Part Number

CSM9S12XDT512SLK

KIT STUDENT LEARNING 16BIT

Manufacturer

Freescale Semiconductor

Lead Free Status / RoHS Status

Lead free / RoHS Compliant

Chapter 6 XGATE (S12XGATEV2)

The XGATE module offers a set of eight hardware semaphores. These semaphores provide a mechanism

to protect system resources that are shared between two concurrent threads of program execution; one

thread running on the S12X_CPU and one running on the XGATE RISC core.

Each semaphore can only be in one of the three states: “Unlocked”, “Locked by S12X_CPU”, and “Locked

by XGATE”. The S12X_CPU can check and change a semaphore’s state through the XGATE semaphore

this through its SSEM and CSEM instructions.

illustrates the valid state transitions.

Section 6.3.1.6, “XGATE Semaphore Register

SSEM Instruction

CSEM Instruction

Figure 6-21. Semaphore State Transitions

MC9S12XDP512 Data Sheet, Rev. 2.21

CSEM Instruction

SSEM Instruction

(XGSEM)”). The RISC core does

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