ask about W5500 receive buffer write pointer

Question

Hello there… i read the W5500 datasheet. If W5500 receives data on socket 0, then S0_RX_WR pointer register will be added with data size. then I must get the data from socket 0 receive buffer, as many as S0_RX_RSR. and then i must update the S0_RX_RD pointer register to the increased value as many as the reading size, and send RECV command to notify W5500 that i have collect the new data. I use 2KB buffer for socket 0 here. My question is, eventually the S0_RX_WR will reach 2048 or more, but the buffer size is only 2048 bytes. The pointer will exceed the buffer size. Is there any way to reset the S0_RX_WR to 0 everytime i have collect the data? I don’t want to CLOSE / DISCONNECT socket every time a new data comes.

becky · Answer

It is not a problem for Sn_RX_WR to exceed 2048. Socket is also not CLOSE. You can write code and read data in the flow shown below. { /* get Received Size */ get_size = Sn_RX_RSR; /* calculate SOCKET n RX Buffer Size & Offset Address */ gSn_RX_MAX = Sn_RXBUF_SIZE * 1024; get_offset = Sn_RX_RD & gSn_RX_MASK; 60 / 109 W5100S Datasheet Version1.0.0 /* calculate Read Offset Address */ get_start_address = gSn_RX_BASE + get_offset; /* if overflow the upper boundary of SOCKET n RX Buffer */ If( (get_offset + get_size) > gSn_RX_MAX ) { /* copy upper_size bytes of get_start_address to destination_address - destination_address is user data memory address */ upper_size = gSn_RX_MAX – get_offset; memcpy(get_start_address, destination_address, upper_size); destination_address += upper_size; /* copy the remained size bytes of gSn_RX_BASE to destination_address */ remained_size = get_size – upper_size; memcpy(gSn_RX_BASE, destination_address, remained_size); } else { /* copy get_size of get_start_address to destination_address */ memcpy(get_start_address, destination_address, get_size); } /* increase Sn_RX_RD as get_size */ Sn_RX_RD += get_size; /* set RECV Command */ Sn_CR[RECV] = ‘1’; while(Sn_CR != 0x00); /* wait until RECV Command is cleared*/ }

kejuqeju · Answer

Ok, i have successfully applied you algorithm… thank you.