Functions
void	SMPHAcquire (uint32_t ui32Semaphore)
	Acquire a semaphore. More...

static bool	SMPHTryAcquire (uint32_t ui32Semaphore)
	Try to Acquire a semaphore. More...

static void	SMPHRelease (uint32_t ui32Semaphore)
	Release a semaphore. More...

Detailed Description

Introduction

The MCU Semaphore offers 32 semaphores that each can be claimed and released in an atomic operation. One and only one semaphore can be handled during a transaction.

Claiming a semaphore causes subsequent claims/reads to return '0' (i.e. "not available"). How the semaphores are used and respected is decided by software.

API

The API functions can be grouped like this:

Semaphore acquire:

Semaphore release:

SMPHRelease()

Function Documentation

§ SMPHAcquire()

void SMPHAcquire ( uint32_t ui32Semaphore )

Acquire a semaphore.

This function acquires the given semaphore, blocking the call until the semaphore is available.

Parameters

ui32Semaphore

is the semaphore number.

Returns: None

 {
     // Check the arguments.
     ASSERT((ui32Semaphore == SMPH_0) ||
            (ui32Semaphore == SMPH_1) ||
            (ui32Semaphore == SMPH_2) ||
            (ui32Semaphore == SMPH_3) ||
            (ui32Semaphore == SMPH_4) ||
            (ui32Semaphore == SMPH_5) ||
            (ui32Semaphore == SMPH_6) ||
            (ui32Semaphore == SMPH_7) ||
            (ui32Semaphore == SMPH_8) ||
            (ui32Semaphore == SMPH_9) ||
            (ui32Semaphore == SMPH_10) ||
            (ui32Semaphore == SMPH_11) ||
            (ui32Semaphore == SMPH_12) ||
            (ui32Semaphore == SMPH_13) ||
            (ui32Semaphore == SMPH_14) ||
            (ui32Semaphore == SMPH_15) ||
            (ui32Semaphore == SMPH_16) ||
            (ui32Semaphore == SMPH_17) ||
            (ui32Semaphore == SMPH_18) ||
            (ui32Semaphore == SMPH_19) ||
            (ui32Semaphore == SMPH_20) ||
            (ui32Semaphore == SMPH_21) ||
            (ui32Semaphore == SMPH_22) ||
            (ui32Semaphore == SMPH_23) ||
            (ui32Semaphore == SMPH_24) ||
            (ui32Semaphore == SMPH_25) ||
            (ui32Semaphore == SMPH_26) ||
            (ui32Semaphore == SMPH_27) ||
            (ui32Semaphore == SMPH_28) ||
            (ui32Semaphore == SMPH_29) ||
            (ui32Semaphore == SMPH_30) ||
            (ui32Semaphore == SMPH_31));
 
     // Wait for semaphore to be release such that it can be claimed
     // Semaphore register reads 1 when lock was acquired otherwise 0
     // (i.e. SMPH_CLAIMED).
     while(HWREG(SMPH_BASE + SMPH_O_SMPH0 + 4 * ui32Semaphore) ==
             SMPH_CLAIMED)
     {
     }
 }

§ SMPHRelease()

static void SMPHRelease ( uint32_t ui32Semaphore )

inlinestatic

Release a semaphore.

This function releases the given semaphore.

Note: It is up to the application to provide the convention for clearing semaphore.

Parameters

ui32Semaphore

is the semaphore number.

Returns: None

 {
     // Check the arguments.
     ASSERT((ui32Semaphore == SMPH_0) ||
            (ui32Semaphore == SMPH_1) ||
            (ui32Semaphore == SMPH_2) ||
            (ui32Semaphore == SMPH_3) ||
            (ui32Semaphore == SMPH_4) ||
            (ui32Semaphore == SMPH_5) ||
            (ui32Semaphore == SMPH_6) ||
            (ui32Semaphore == SMPH_7) ||
            (ui32Semaphore == SMPH_8) ||
            (ui32Semaphore == SMPH_9) ||
            (ui32Semaphore == SMPH_10) ||
            (ui32Semaphore == SMPH_11) ||
            (ui32Semaphore == SMPH_12) ||
            (ui32Semaphore == SMPH_13) ||
            (ui32Semaphore == SMPH_14) ||
            (ui32Semaphore == SMPH_15) ||
            (ui32Semaphore == SMPH_16) ||
            (ui32Semaphore == SMPH_17) ||
            (ui32Semaphore == SMPH_18) ||
            (ui32Semaphore == SMPH_19) ||
            (ui32Semaphore == SMPH_20) ||
            (ui32Semaphore == SMPH_21) ||
            (ui32Semaphore == SMPH_22) ||
            (ui32Semaphore == SMPH_23) ||
            (ui32Semaphore == SMPH_24) ||
            (ui32Semaphore == SMPH_25) ||
            (ui32Semaphore == SMPH_26) ||
            (ui32Semaphore == SMPH_27) ||
            (ui32Semaphore == SMPH_28) ||
            (ui32Semaphore == SMPH_29) ||
            (ui32Semaphore == SMPH_30) ||
            (ui32Semaphore == SMPH_31));
 
     // No check before release, it is up to the application to provide the
     // conventions for who and when a semaphore can be released.
     HWREG(SMPH_BASE + SMPH_O_SMPH0 + 4 * ui32Semaphore) = SMPH_FREE;
 }

§ SMPHTryAcquire()

static bool SMPHTryAcquire ( uint32_t ui32Semaphore )

inlinestatic

Try to Acquire a semaphore.

This function tries to acquire the given semaphore, if the semaphore could not be claimed the function returns false.

Parameters

ui32Semaphore

is the semaphore number.

Returns

Returns if a semaphore was acquired

true : Semaphore acquired.
false : Semaphore not acquired.

 {
     uint32_t ui32SemaReg;
 
     // Check the arguments.
     ASSERT((ui32Semaphore == SMPH_0) ||
            (ui32Semaphore == SMPH_1) ||
            (ui32Semaphore == SMPH_2) ||
            (ui32Semaphore == SMPH_3) ||
            (ui32Semaphore == SMPH_4) ||
            (ui32Semaphore == SMPH_5) ||
            (ui32Semaphore == SMPH_6) ||
            (ui32Semaphore == SMPH_7) ||
            (ui32Semaphore == SMPH_8) ||
            (ui32Semaphore == SMPH_9) ||
            (ui32Semaphore == SMPH_10) ||
            (ui32Semaphore == SMPH_11) ||
            (ui32Semaphore == SMPH_12) ||
            (ui32Semaphore == SMPH_13) ||
            (ui32Semaphore == SMPH_14) ||
            (ui32Semaphore == SMPH_15) ||
            (ui32Semaphore == SMPH_16) ||
            (ui32Semaphore == SMPH_17) ||
            (ui32Semaphore == SMPH_18) ||
            (ui32Semaphore == SMPH_19) ||
            (ui32Semaphore == SMPH_20) ||
            (ui32Semaphore == SMPH_21) ||
            (ui32Semaphore == SMPH_22) ||
            (ui32Semaphore == SMPH_23) ||
            (ui32Semaphore == SMPH_24) ||
            (ui32Semaphore == SMPH_25) ||
            (ui32Semaphore == SMPH_26) ||
            (ui32Semaphore == SMPH_27) ||
            (ui32Semaphore == SMPH_28) ||
            (ui32Semaphore == SMPH_29) ||
            (ui32Semaphore == SMPH_30) ||
            (ui32Semaphore == SMPH_31));
 
     // Semaphore register reads 1 if lock was acquired
     // (i.e. SMPH_FREE).
     ui32SemaReg = HWREG(SMPH_BASE + SMPH_O_SMPH0 + 4 * ui32Semaphore);
 
     return (ui32SemaReg == SMPH_FREE);
 }