Porting usart for receiving data

Hi, all

I'm trying to solve stream-broken in usart through MF.

Through usart bus, 21760 bytes as speed of 250kbps should be transferred. When I tested with netduino based PK with large buffer(I modified RxQueue to receive all data), sometimes data is missing. Every time the index of missing is changing, so I think it is not related with logic in C# app.

Below is a part of netduino source related with USART.

 

void STM32_USART_Handle_RX_IRQ (int ComPortNum, USART_TypeDef* uart)
{   
	INTERRUPT_START;   
	char c = (char)(uart->DR); // read RX data   
	USART_AddCharToRxBuffer(ComPortNum, c);   
	Events_Set(SYSTEM_EVENT_FLAG_COM_IN);   
	INTERRUPT_END;
}

I thought it is related with AddCharToRxBuffer, so I used this test code in Keil with debugger.
(the length of data is fixed, so I used MAX_STRLEN for checking stream is finished)

 

?

void STM32_USART_Handle_RX_IRQ (int ComPortNum, USART_TypeDef* uart)
{
	INTERRUPT_START;
	if(cnt < MAX_STRLEN)
	{
		char c = (char)(uart->DR); // read RX data
		received_string[cnt] = (char)(uart->DR);
		cnt++;
	}
	else
	{
		for(int i = 0; i < MAX_STRLEN; i++)
		{
			USART_AddCharToRxBuffer(ComPortNum, received_string[i]);
			Events_Set(SYSTEM_EVENT_FLAG_COM_IN);
		}
		cnt = 0;
	}
	INTERRUPT_END;
}

When I confirm the data in received_string array while PC is hang in else condition, the data is different with original one.

Now I am suppose it is timing issue.
- Usart Interrupt Clock or
- Thread/Timer issue related with other core function or

I'm not expert in native and embedded, so I'm checking every module one by one. I wonder which part can be related with this issue.


P.S. I tested also native example, and it works. So this is not hardware problem.

Jiwon