W5500 UDP sending timeout (Sn_IR always is 0x08)

Question

I have successfully used a W5500 to behave as a TCP server on several ports, but I am trying to send a UDP request to a NTP server, but whenever I send a Send via Sn_CR the Sn_IR always reports 0x08 (ie a timeout error), although setting up and opening the port is always ok. According to Wireshark, the only traffic on the network is an ARP request to 0.0.0.0. I am using fixed IPs and the Destination IP and port (123) in Sn_DIPR and Sn_DPORT respectively, 1024 in Sn_PORT (not 100% sure this is correct though) and havent written anything into Sn_DHAR. The W5500s MAC, IP, mask, and gateway is set in SHAR, SIPR, SUBR, and GAR. PORT INIT: unsigned long Timeout; unsigned short int SrcPort = 1024;//anything over 1023 unsigned char ServerIP[4], SR; NetworkSettingsStruct NetSettings; WriteByteToWiznet5500( SOCKET_MR, BSB_Socket, SOCKET_MODE_UDP ); // sets TCP/UDP mode WriteByteToWiznet5500( ADDR_RCR, BSB_Socket, 3 ); GetModbusEthernetSettings( &NetSettings ); ServerIP[0] = (unsigned char)NetSettings.NTSAddress[0]; ServerIP[1] = (unsigned char)NetSettings.NTSAddress[1]; ServerIP[2] = (unsigned char)NetSettings.NTSAddress[2]; ServerIP[3] = (unsigned char)NetSettings.NTSAddress[3]; WriteArrayToWiznet5500( SOCKET_DIPR0, BSB_SOCKET_3_TX, ServerIP, 4 ); //src WriteByteToWiznet5500( SOCKET_PORT0, BSB_SOCKET_3_TX, (1024)>>8 ); WriteByteToWiznet5500( SOCKET_PORT1, BSB_SOCKET_3_TX, (1024)&0x00ff ); //dest....typically 123 WriteByteToWiznet5500( SOCKET_DPORT0, BSB_SOCKET_3_TX, (NetSettings.NTS_UDPPort) >>8 ); WriteByteToWiznet5500( SOCKET_DPORT1, BSB_SOCKET_3_TX, (NetSettings.NTS_UDPPort) &0x00ff ); //clear any outstanding interrupt flags WriteByteToWiznet5500( SOCKET_IR, BSB_Socket, 0x1f ); //Open socket Timeout = _CP0_GET_COUNT() + WIZZNET_TIMEOUT_500ms; WriteByteToWiznet5500( SOCKET_CR, BSB_Socket, SOCKET_CMD_OPEN ); while( (SR=ReadByteFromWiznet5500( SOCKET_SR, BSB_Socket )) != SOCKET_STAT_SOCK_UDP ) { if( _CP0_GET_COUNT()>Timeout ) return 0; } return SOCKET_STAT_SOCK_UDP; PORT SEND: unsigned short int RxSize, OffsetAddress, i; NPTStruct NetTimeReq; unsigned char IR; unsigned long int Timeout; //clear the request to all zeros, except the 3 bit VN=4, And Mode=3 (ie client) memset( &NetTimeReq, 0x00, sizeof(NetTimeReq) ); NetTimeReq.ModeBits = 0x1b;//(4<<2) | (0x03<<5); OffsetAddress = ReadUINT16FromWiznet5500( SOCKET_TX_WR0, BSB_SOCKET_3_REG); WriteArrayToWiznet5500( OffsetAddress, BSB_SOCKET_3_TX, &NetTimeReq, sizeof(NetTimeReq) ); OffsetAddress = OffsetAddress + sizeof(NetTimeReq); WriteUINT16ToWiznet5500( SOCKET_TX_WR0, BSB_SOCKET_3_REG, OffsetAddress ); WriteByteToWiznet5500( SOCKET_CR, BSB_SOCKET_3_REG, SOCKET_CMD_SEND ); Timeout = _CP0_GET_COUNT() + WIZZNET_TIMEOUT_900ms; while( (IR = ReadByteFromWiznet5500( SOCKET_IR, BSB_SOCKET_3_REG)) == 0x00 ) { // if( _CP0_GET_COUNT() > Timeout ) // return 0; } //clear down the interrupt/flag for next time WriteByteToWiznet5500( SOCKET_IR, BSB_SOCKET_3_REG, IR ); if( IR == SOCKET_INT_SENDOK ) return 1; else return 0…

AJ1999 · Answer

Further information: Despite setting the Destination Target to 192.168.18.100 the ARP requests on the network dont seem to be asking for this, but 0.0.0.0 instead: image859×502 25.1 KB Furthermore, if I load Sn_DHAR with the MAC address of the destination and use SENDMAC instead of SEND there are no corresponding ARP requests but the NTP packet is spotted with the destination still set to 0.0.0.0. image699×571 27.9 KB

Mxyxixptlick · Answer

I see in your code where you set your server IP address and where you set the server and destination ports but I don’t see any code that sets the destination IP address.

Mxyxixptlick · Answer

Try reading the server IP from the W5500 SIPR register after you set it, and see if it has the value you expect.