I2C peripheral (STM8S005C6) unable to detect stop event

[Darryl Weimers]

Posted on September 05, 2017 at 22:17

I2C peripheral of STM8S005C6 stop event interrupt not triggered

:Using an external device (verified to be working), I generate an I2C signal (100KHz) to communicate with

STM8S005C6

program as a

slave

receiver with the

7-bit address of 0x24

.

I2C interrupt service routine is triggered by an incoming I2C signal. Address match and data receive events are detected. However, stop event (I2C_EVENT_SLAVE_STOP_DETECTED) is not detected.  Through a digital logic analyzer, I see that each byte received has been acknowledged. And, stop condition is present.

 

For firmware side

, I am using the I2C example code with modifications provided by STM :

/external-link.jspa?url=http%3A%2F%2Fwww.st.com%2Fen%2Fembedded-software%2Fstsw-stm8069.html

 

**********************************************C

ode Below

*******************************

&sharpinclude ''stm8s.h''

&sharpinclude ''stm8s_clk.h''&sharpinclude ''stm8s_i2c.h''&sharpinclude ''stm8s_gpio.h''&sharpinclude ''stm8s_it.h''

void main(void){

//

**************************************

Clock setup (16 MHz Internal clock + I2C peripheral clock) CLK_DeInit();

CLK_HSECmd(DISABLE);

CLK_LSICmd(DISABLE);CLK_ClockSwitchCmd(DISABLE);CLK_HSICmd(ENABLE);

while(CLK_GetFlagStatus(CLK_FLAG_HSIRDY) == FALSE);

CLK_HSIPrescalerConfig(CLK_PRESCALER_HSIDIV1);

CLK_SYSCLKConfig(CLK_PRESCALER_CPUDIV1);

CLK_PeripheralClockConfig(CLK_PERIPHERAL_SPI, DISABLE);

CLK_PeripheralClockConfig(CLK_PERIPHERAL_I2C, ENABLE);CLK_PeripheralClockConfig(CLK_PERIPHERAL_ADC, DISABLE);CLK_PeripheralClockConfig(CLK_PERIPHERAL_AWU, DISABLE);CLK_PeripheralClockConfig(CLK_PERIPHERAL_UART1, DISABLE);CLK_PeripheralClockConfig(CLK_PERIPHERAL_TIMER1, DISABLE);CLK_PeripheralClockConfig(CLK_PERIPHERAL_TIMER2, DISABLE);CLK_PeripheralClockConfig(CLK_PERIPHERAL_TIMER4, DISABLE);

//**************************************GPIO setup

GPIO_DeInit(GPIOB);GPIO_Init(GPIOB, GPIO_PIN_4, GPIO_MODE_OUT_OD_HIZ_FAST);GPIO_Init(GPIOB, GPIO_PIN_5, GPIO_MODE_OUT_OD_HIZ_FAST);

//

**************************************

I2C setup (100KHz, 7 bit address mode, all I2C interrupt enable, address: 0x24)  I2C_DeInit();I2C_Init(100000,             (0x24<<1),             I2C_DUTYCYCLE_2,             I2C_ACK_CURR,             I2C_ADDMODE_7BIT,            (CLK_GetClockFreq() / 1000000));I2C_Cmd(ENABLE);

I2C_ITConfig((I2C_IT_TypeDef)(I2C_IT_ERR | I2C_IT_EVT | I2C_IT_BUF), ENABLE);

// ***********************************************Enable general interruptsenableInterrupts();

while(1); 

}

// Excerpt from file ''stm8s_it.c''

INTERRUPT_HANDLER(I2C_IRQHandler, 19)

{/* Read SR2 register to get I2C error */if ((I2C->SR2) != 0){/* Clears SR2 register */I2C->SR2 = 0;

}

Event = I2C_GetLastEvent();switch (Event){/* check on EV1*/case I2C_EVENT_SLAVE_RECEIVER_ADDRESS_MATCHED:

Rx_Idx = 0;

break;

/* Check on EV2*/

case I2C_EVENT_SLAVE_BYTE_RECEIVED:Slave_Buffer_Rx[Rx_Idx++] = I2C_ReceiveData();break;

/* Check on EV4 */

case (I2C_EVENT_SLAVE_STOP_DETECTED):/* write to CR2 to clear STOPF flag */I2C->CR2 |= I2C_CR2_ACK;break;

default:

break;}

}

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