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[Core] Fixes I2C slave
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@avtolstoy @m-mcgowan
avtolstoy authored and m-mcgowan committed Jan 23, 2018
1 parent 7a5fda4 commit 5cee525
Showing 1 changed file with 68 additions and 20 deletions.
88 changes: 68 additions & 20 deletions hal/src/core/i2c_hal.c
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Expand Up @@ -83,6 +83,8 @@ typedef struct STM32_I2C_Info {
void (*callback_onReceive)(int);

I2C_Mode mode;

uint8_t clkStretchingEnabled;
} STM32_I2C_Info;

/*
Expand All @@ -108,6 +110,17 @@ static void HAL_I2C_SoftwareReset(HAL_I2C_Interface i2c)
I2C_SoftwareResetCmd(i2cMap[i2c]->I2C_Peripheral, ENABLE);
I2C_SoftwareResetCmd(i2cMap[i2c]->I2C_Peripheral, DISABLE);

/* Clear all I2C interrupt error flags, and re-enable them */
I2C_ClearITPendingBit(i2cMap[i2c]->I2C_Peripheral, I2C_IT_SMBALERT | I2C_IT_PECERR |
I2C_IT_TIMEOUT | I2C_IT_ARLO | I2C_IT_OVR | I2C_IT_BERR | I2C_IT_AF);
I2C_ITConfig(i2cMap[i2c]->I2C_Peripheral, I2C_IT_ERR, ENABLE);

/* Re-enable Event and Buffer interrupts in Slave mode */
if(i2cMap[i2c]->mode == I2C_MODE_SLAVE)
{
I2C_ITConfig(i2cMap[i2c]->I2C_Peripheral, I2C_IT_EVT | I2C_IT_BUF, ENABLE);
}

/* Enable the I2C peripheral */
I2C_Cmd(i2cMap[i2c]->I2C_Peripheral, ENABLE);

Expand All @@ -133,6 +146,8 @@ void HAL_I2C_Init(HAL_I2C_Interface i2c, void* reserved)
i2cMap[i2c]->txBufferLength = 0;

i2cMap[i2c]->transmitting = 0;

i2cMap[i2c]->clkStretchingEnabled = 1;
}

void HAL_I2C_Set_Speed(HAL_I2C_Interface i2c, uint32_t speed, void* reserved)
Expand All @@ -155,6 +170,8 @@ void HAL_I2C_Stretch_Clock(HAL_I2C_Interface i2c, bool stretch, void* reserved)
{
I2C_StretchClockCmd(i2cMap[i2c]->I2C_Peripheral, DISABLE);
}

i2cMap[i2c]->clkStretchingEnabled = stretch;
}

void HAL_I2C_Begin(HAL_I2C_Interface i2c, I2C_Mode mode, uint8_t address, void* reserved)
Expand All @@ -166,6 +183,8 @@ void HAL_I2C_Begin(HAL_I2C_Interface i2c, I2C_Mode mode, uint8_t address, void*
i2cMap[i2c]->txBufferLength = 0;
i2cMap[i2c]->mode = mode;

i2cMap[i2c]->mode = mode;

/* Enable I2C clock */
*i2cMap[i2c]->I2C_RCC_APBRegister |= i2cMap[i2c]->I2C_RCC_APBClockEnable;

Expand Down Expand Up @@ -601,15 +620,48 @@ static void HAL_I2C_ER_InterruptHandler(HAL_I2C_Interface i2c)
* @param None
* @retval None
*/
void I2C1_ER_irq(void)
void HAL_I2C1_ER_Handler(void)
{
HAL_I2C_ER_InterruptHandler(HAL_I2C_INTERFACE1);
}

static void HAL_I2C_EV_InterruptHandler(HAL_I2C_Interface i2c)
{
/* According to reference manual Figure 219 (http://www.st.com/web/en/resource/technical/document/reference_manual/CD00225773.pdf):
* 3. After checking the SR1 register content, the user should perform the complete clearing sequence for each
* flag found set.
* Thus, for ADDR and STOPF flags, the following sequence is required inside the I2C interrupt routine:
* READ SR1
* if (ADDR == 1) {READ SR1; READ SR2}
* if (STOPF == 1) {READ SR1; WRITE CR1}
* The purpose is to make sure that both ADDR and STOPF flags are cleared if both are found set
*/
uint32_t sr1 = I2C_ReadRegister(i2cMap[i2c]->I2C_Peripheral, I2C_Register_SR1);

/* EV4 */
if (sr1 & I2C_EVENT_SLAVE_STOP_DETECTED)
{
/* software sequence to clear STOPF */
I2C_GetFlagStatus(i2cMap[i2c]->I2C_Peripheral, I2C_FLAG_STOPF);
// Restore clock stretching settings
// This will also clear EV4
I2C_StretchClockCmd(i2cMap[i2c]->I2C_Peripheral, i2cMap[i2c]->clkStretchingEnabled ? ENABLE : DISABLE);
//I2C_Cmd(i2cMap[i2c]->I2C_Peripheral, ENABLE);

i2cMap[i2c]->rxBufferLength = i2cMap[i2c]->rxBufferIndex;
i2cMap[i2c]->rxBufferIndex = 0;

if(NULL != i2cMap[i2c]->callback_onReceive)
{
// alert user program
i2cMap[i2c]->callback_onReceive(i2cMap[i2c]->rxBufferLength);
}
}

uint32_t st = I2C_GetLastEvent(i2cMap[i2c]->I2C_Peripheral);

/* Process Last I2C Event */
switch (I2C_GetLastEvent(i2cMap[i2c]->I2C_Peripheral))
switch (st)
{
/********** Slave Transmitter Events ************/

Expand All @@ -626,6 +678,7 @@ static void HAL_I2C_EV_InterruptHandler(HAL_I2C_Interface i2c)
}

i2cMap[i2c]->txBufferIndex = 0;

break;

/* Check on EV3 */
Expand All @@ -635,6 +688,13 @@ static void HAL_I2C_EV_InterruptHandler(HAL_I2C_Interface i2c)
{
I2C_SendData(i2cMap[i2c]->I2C_Peripheral, i2cMap[i2c]->txBuffer[i2cMap[i2c]->txBufferIndex++]);
}
else
{
// If no data is loaded into DR register and clock stretching is enabled,
// the device will continue pulling SCL low. To avoid that, disable clock stretching
// when the tx buffer is exhausted to release SCL.
I2C_StretchClockCmd(i2cMap[i2c]->I2C_Peripheral, DISABLE);
}
break;

/*********** Slave Receiver Events *************/
Expand All @@ -648,23 +708,11 @@ static void HAL_I2C_EV_InterruptHandler(HAL_I2C_Interface i2c)
/* Check on EV2*/
case I2C_EVENT_SLAVE_BYTE_RECEIVED:
case (I2C_EVENT_SLAVE_BYTE_RECEIVED | I2C_SR1_BTF):
i2cMap[i2c]->rxBuffer[i2cMap[i2c]->rxBufferIndex++] = I2C_ReceiveData(i2cMap[i2c]->I2C_Peripheral);
break;

/* Check on EV4 */
case I2C_EVENT_SLAVE_STOP_DETECTED:
/* software sequence to clear STOPF */
I2C_GetFlagStatus(i2cMap[i2c]->I2C_Peripheral, I2C_FLAG_STOPF);
I2C_Cmd(i2cMap[i2c]->I2C_Peripheral, ENABLE);

i2cMap[i2c]->rxBufferLength = i2cMap[i2c]->rxBufferIndex;
i2cMap[i2c]->rxBufferIndex = 0;

if(NULL != i2cMap[i2c]->callback_onReceive)
{
// alert user program
i2cMap[i2c]->callback_onReceive(i2cMap[i2c]->rxBufferLength);
}
// Prevent RX buffer overflow
if (i2cMap[i2c]->rxBufferIndex < BUFFER_LENGTH)
i2cMap[i2c]->rxBuffer[i2cMap[i2c]->rxBufferIndex++] = I2C_ReceiveData(i2cMap[i2c]->I2C_Peripheral);
else
(void)I2C_ReceiveData(i2cMap[i2c]->I2C_Peripheral);
break;

default:
Expand All @@ -677,7 +725,7 @@ static void HAL_I2C_EV_InterruptHandler(HAL_I2C_Interface i2c)
* @param None
* @retval None
*/
void I2C1_EV_irq(void)
void HAL_I2C1_EV_Handler(void)
{
HAL_I2C_EV_InterruptHandler(HAL_I2C_INTERFACE1);
}
Expand Down

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