--- title: "W5500 TCP Server Mode" url: "https://maker.wiznet.io/forum/13199" markdown_url: "https://maker.wiznet.io/forum/13199/md" type: "Forum topic" category: "Ethernet Chips" author: "Century" created: "2019-02-04T11:00:00+09:00" last_activity: "2019-02-06T00:52:12+09:00" language: "en" views: 1738 replies: 14 source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)" --- # W5500 TCP Server Mode ## Question Asked by Century on 2019-02-04 in Ethernet Chips. Hi, I have configured the W5500 chip in TCP server mode and Receiving and Transmission is working fine. But after some time while transmitting the Sn_IR becomes Socket Busy. The response I am getting for Sn_IR is 0x01 instead of 0x11. Please help me! ## Replies ### Reply 1 by Eugeny, 2019-02-04 ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > Sn_IR becomes Socket Busy There’s no such state for the socket. ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > The response I am getting for Sn_IR is 0x01 instead of 0x11. Bit 4 set means SEND_OK. > Sn_IR(SENDOK) Interrupt > This is issued when SEND command is completed. If this bit is reset, then either respective bit is not set in Sn_IMR, or there were no completed SEND command, or this bit was cleared by the user code. ### Reply 2 by Century, 2019-02-04 (in reply to reply 1) If SEND_OK command is reset, I am making it set and transmitting again. But sometimes I am getting Sn_SR command 0x1E or 0x2E, after that it goes to close state and again I am calling Initialization of W5500 chip. What could be the problem? ### Reply 3 by Eugeny, 2019-02-04 ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > If SEND_OK command is reset SEND_OK is not a command, it is flag in Sn_IR register. ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > I am making it set and transmitting again. How you do it? You mean in Sn_IMR register? ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > But sometimes I am getting Sn_SR command 0x1E or 0x2E Sounds like invalid states. Are you sure SPI communication is reliable? ### Reply 4 by Century, 2019-02-04 Eugeny: > > I am making it set and transmitting again. > > How you do it? You mean in Sn_IMR register? I making as follows if I got wrong response setSn_CR(sn,Sn_CR_SEND); // sn = Socket Number = 0, Sn_CR_SEND = 0x10 /* wait to process the command… */ while(getSn_CR(sn)); Eugeny: > Are you sure SPI communication is reliable? As of now I thought it is working properly, But is it require some delay between executing commands? Eugeny: > SEND_OK is not a command Sorry for that wrong statement. ### Reply 5 by Eugeny, 2019-02-04 ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > I making as follows if I got wrong response What wrong response you are talking about? ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > // sn = Socket Number = 0, Sn_CR_SEND = 0x10 SEND command is code 0x20. Code 0x10 is to close socket! ### Reply 6 by Century, 2019-02-04 I am calling this function every one sec. This library is downloaded from the github. int32_t send(uint8_t sn, uint8_t * buf, uint16_t len) { uint8_t tmp=0; uint16_t freesize=0; CHECK_SOCKNUM(); CHECK_SOCKMODE(Sn_MR_TCP); CHECK_SOCKDATA(); tmp = getSn_SR(sn); if(tmp != SOCK_ESTABLISHED && tmp != SOCK_CLOSE_WAIT) return SOCKERR_SOCKSTATUS; if( sock_is_sending & (1<<sn) ) { `**> tmp = getSn_IR(sn);**` Sometimes I am getting wrong response _NOP() ; _NOP() ; ``` if(tmp & Sn_IR_SENDOK) { setSn_IR(sn, Sn_IR_SENDOK); _NOP() ; _NOP() ; sock_is_sending &= ~(1< freesize) len = freesize; // check size not to exceed MAX size. while(1) { freesize = getSn_TX_FSR(sn); _NOP() ; _NOP() ; tmp = getSn_SR(sn); if ((tmp != SOCK_ESTABLISHED) && (tmp != SOCK_CLOSE_WAIT)) { // close(sn); return SOCKERR_SOCKSTATUS; } if( (sock_io_mode & (1<<sn)) && (len > freesize) ) return SOCK_BUSY; if(len <= freesize) break; } wiz_send_data(sn, buf, len); _NOP() ; _NOP() ; setSn_CR(sn,Sn_CR_SEND); /* wait to process the command… */ while(getSn_CR(sn)); sock_is_sending |= (1 << sn); //M20150409 : Explicit Type Casting //return len; return (int32_t)len; } Eugeny: > SEND command is code 0x20. Code 0x10 is to close socket! Actually this function I am calling. setSn_IR(sn, Sn_IR_SENDOK); ### Reply 7 by Eugeny, 2019-02-04 ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > **> tmp = getSn_IR(sn);** > Sometimes I am getting wrong response What is wrong with this command’s response? ### Reply 8 by Century, 2019-02-04 As I said I am getting 0x0E, 0x1E, 0x2E. I am expecting 0x11 response. Can you please guide me which software is good for TCP/IP communication testing. ### Reply 9 by Eugeny, 2019-02-04 ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > As I said I am getting 0x0E, 0x1E, 0x2E. For Sn_IR? ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > But sometimes I am getting Sn_SR command 0x1E or 0x2E Or for Sn_SR? Please do not confuse the things because if you describe your issue improperly it will be close to impossible to help you. If 0x2E is about Sn_IR, can you figur eout what have happened using datasheet page 49? ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > I am expecting 0x11 response. Why? Why do you think there could be no other response than this? Do you actually reset the flags? ### Reply 10 by Century, 2019-02-04 Eugeny: > For Sn_IR? Sorry for wrong direction, The response I am getting for Sn_IR. Eugeny: > Do you actually reset the flags? Yes, Because the data is transmitting properly about 40 sec, sometimes about 10 sec. But most of the time 0x01 response I will get for Sn_IR, Actually I am again setting the SEND_OK flag, but after if I read it will be 0x01. ### Reply 11 by Eugeny, 2019-02-04 ![](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/48.png) Century: > I am again setting the SEND_OK flag How do you “set” this flag (did I ask this question before?..) ### Reply 12 by Century, 2019-02-04 (in reply to reply 1) Eugeny: > If this bit is reset, then either respective bit is not set in Sn_IMR, or there were no completed SEND command, or this bit was cleared by the user code. This thread, May be I thought wrong, ### Reply 13 by Eugeny, 2019-02-04 I think the best at this point for you is to read datasheet regarding the information on IR/IMR and Sn_IR/Sn_IMR flags and ask exact questions on things you do not understand. So far sounds you have some idea of how it may work, but it seems it does not… ### Reply 14 by Mxyxixptlick, 2019-02-06 You wrote: “But is it require some delay between executing commands?” Yes, it does. After sending a command you should first wait for Sn_CR to be set to zero, then check Sn_SR for the status code(s) that may result from that command (e.g., for a “CLOSE” command you’d expect Sn_SR to change to SOCK_CLOSED). See page 47 of the datasheet, which says (in part): “**Sn_CR (Socket n Command Register) [R/W] [0x0001] [0x00]** This is used to set the command for Socket n such as OPEN, CLOSE, CONNECT, LISTEN, SEND, and RECEIVE. After W5500 accepts the command, the Sn_CR register is automatically cleared to 0x00. Even though Sn_CR is cleared to 0x00, the command is still being processed. To check whether the command is completed or not, please check the Sn_IR or Sn_SR.” In addition, I’ve found that when running with a Cortex-M4 MCU at 120 MHz I need to insert delays in loops in which I’m polling the status register. Failing to do so seems to be especially harmful when sending a CONNECT or DISCON command, both of which require a handshake with a network peer. I suspect that polling too frequently interferes with the W5500’s ability to monitor the network. --- Source: https://maker.wiznet.io/forum/13199