Posted on January 13, 2017 at 14:51
edit: previously I wrote that problems occurs with freertos, I checked without it and I am having the same problem (ending in dead loop after sending more than 8 characters).
Steps to reproduce:
Create project in CubeMX for STM32F4DISCOVERY, enable USB_FS Device only. Configure clock: PLL_N = 72, PLL_Q=3, that gives me 48 MHz for usb, other settings remain unchanged. In configuration I enable CDC device with default parameters. Generate code for SW.
I add some led toggle in order to know it it is running.
/* StartDefaultTask function */
void StartDefaultTask(void const * argument)
{
/* init code for USB_DEVICE */
MX_USB_DEVICE_Init();
/* USER CODE BEGIN 5 */
/* Infinite loop */
for(;;)
{
HAL_GPIO_TogglePin(LD3_GPIO_Port, LD3_Pin);
osDelay(500);
}
/* USER CODE END 5 */
}�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?
In file usbd_cdc_if.c I am setting breakpoint at CDC_Receive_FS function.
When I am sending 8 characters or less it works fine. Program enters function above. When I send more than 8 characters, program is not entering CDC_Receive_FS function
>>> import serial
>>> ser = serial.Serial(port='/dev/ttyACM0')
>>> ser.write('12345678')
8
>>> ser.write('123456789')
9
>>> ser.write('12345678')
# python hangs here�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?
- Sometimes program hangs in this loop:
/**
* @brief This is the code that gets called when the processor receives an
* unexpected interrupt. This simply enters an infinite loop, preserving
* the system state for examination by a debugger.
* @param None
* @retval None
*/
.section .text.Default_Handler,'ax',%progbits
Default_Handler:
Infinite_Loop:
b Infinite_Loop
.size Default_Handler, .-Default_Handler�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?
#stm32f4-discovery #cubemx #usb-cdc #freertos
