Posted on June 24, 2013 at 03:37Hey,,
I want to implement TCP/IP using no OS on MCBSTM32C (STM32F107VC). The driver ETH_STM32x.c file writen by KEIL uses RTX functions in it's receiving part.
<i>Therefore i wrote my own function for receiving a frame, everything else is similar to the driver.
</i>
But it is not working. After a lot of checking,<b> i realised it gets stuck at a certain point(second if condition of loop).
The issue is , the DMA OWN bit in the descriptor is never reset.
why is this problem arising. </b>
Please Help !!!
my receiving function returns the packet length and it writes the data from address:packet .
it returns 0 otherwise.
<pre>
U16 receive_packet( U8 * packet)
{
U32 i,RxLen;
U32 *sp;
i = RxBufIndex;
if (ETH->DMASR &DSR_RS ==0) // check if a packet has been received and buffered
{
return 0;
}
if((Rx_Desc[i].Stat & DMA_RX_OWN) != 0)
{
return 0;
}
if( (Rx_Desc[i].Stat & DMA_RX_ES ==0) && ((Rx_Desc[i].Stat & DMA_RX_SEG_MASK) == DMA_RX_SEG_MASK))
{
RxLen = ((Rx_Desc[i].Stat >> 16) & 0x3FFF) - 4;
sp = (U32 *)(Rx_Desc[i].Addr & ~3);
for (RxLen = (RxLen + 3) >> 2; RxLen; RxLen--)
{
*packet++ = *sp++;
}
}
else
{
RxLen=0;
}
Rx_Desc[i].Stat = DMA_RX_OWN; // Set Own bit of the Rx descriptor Status: gives the buffer back to ETHERNET DMA
if (++i == NUM_RX_BUF) i = 0; RxBufIndex = i;
if (ETH->DMASR & INT_RBUIE)
{ ETH->DMASR = INT_RBUIE; // Rx DMA suspended, resume DMA reception.
ETH->DMARPDR = 0;
}
ETH->DMASR = DSR_NIS | DSR_RS ; // Clear the interrupt pending bits
return(RxLen);
}
</pre>
#mcbstm32c-stm32f107vc-ethernet
