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/*
* I2C.cpp
*
* Created on: 13 May 2019
* Author: David
*/
#include "I2C.h"
#include <Platform/Tasks.h>
#if defined(I2C_IFACE)
static bool i2cInitialised = false;
#endif
// Initialise the I2C interface, if not already done
void I2C::Init() noexcept
{
#if defined(I2C_IFACE)
if (!i2cInitialised)
{
MutexLocker lock(Tasks::GetI2CMutex());
if (!i2cInitialised) // test it again, now that we own the mutex
{
NVIC_SetPriority(I2C_IRQn, NvicPriorityTwi); // we use I2C to talk to the DueX before Platform::InitialiseInterrupts is called, so need to do this here
I2C_IFACE.BeginMaster(I2cClockFreq);
i2cInitialised = true;
}
}
#endif
}
#if defined(I2C_IFACE)
#include "RTOSIface/RTOSIface.h"
static TaskHandle twiTask = nullptr; // the task that is waiting for a TWI command to complete
extern "C" void WIRE_ISR_HANDLER() noexcept
{
WIRE_INTERFACE->TWI_IDR = 0xFFFFFFFF;
TaskBase::GiveFromISR(twiTask); // wake up the task
twiTask = nullptr;
}
uint32_t I2C::statusWaitFunc(Twi *twi, uint32_t bitsToWaitFor) noexcept
{
bool ok = true;
uint32_t sr = twi->TWI_SR;
while (ok && (sr & bitsToWaitFor) == 0)
{
// Suspend this task until we get an interrupt indicating that a status bit that we are interested in has been set
twiTask = TaskBase::GetCallerTaskHandle();
twi->TWI_IDR = 0xFFFFFFFF;
twi->TWI_IER = bitsToWaitFor;
NVIC_EnableIRQ(I2C_IRQn);
ok = TaskBase::Take(2);
twiTask = nullptr;
twi->TWI_IDR = 0xFFFFFFFF;
sr = twi->TWI_SR;
}
return sr;
}
#endif
// End
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