diff --git a/targets/TARGET_STM/i2c_api.c b/targets/TARGET_STM/i2c_api.c index 7ce17c692d..1281e0e933 100644 --- a/targets/TARGET_STM/i2c_api.c +++ b/targets/TARGET_STM/i2c_api.c @@ -590,6 +590,17 @@ int i2c_stop(i2c_t *obj) #endif // Disable reload mode handle->Instance->CR2 &= (uint32_t)~I2C_CR2_RELOAD; + + // Ensure the transmission is started before sending a stop + if ((handle->Instance->CR2 & (uint32_t)I2C_CR2_RD_WRN) == 0) { + timeout = FLAG_TIMEOUT; + while (!__HAL_I2C_GET_FLAG(handle, I2C_FLAG_TXIS)) { + if ((timeout--) == 0) { + return I2C_ERROR_BUS_BUSY; + } + } + } + // Generate the STOP condition handle->Instance->CR2 |= I2C_CR2_STOP;