Ethernet library can hang during data transmission (in socket.cpp: send() ) [imported]

[agdl]

From @cmaglie on November 15, 2012 19:3

This is Issue 1049 moved from a Google Code project. Added by 2012-09-25T02:13:55.000Z by [email protected]. Please review that bug for more context and additional comments, but update this bug.

Original labels: Type-Defect, Priority-Medium

Original description

What steps will reproduce the problem? Difficult to catch the problem since it depends on timing of sending data from the shield while incoming data. Appears to be a coincidence issue on the exact timing. I'm getting it to happen by continually sending data at the fastest rate possible on a TCP socket while the arduino program sends back replies using a sliding window. Even at that, the problem takes several hours to hit, but when it does it is catastrophic.

What version of the Arduino software are you using? On what operating system? Which Arduino board are you using? Arduino 1.01 with a Mega 2560 and ethernet shield (W5100).

Please provide any additional information below. I've traced the problem to socket.cpp:send() by putting debug outputs to the serial port if it gets stuck in a loop there. Here's the instrumented code:

uint16_t send(SOCKET s, const uint8_t * buf, uint16_t len) { uint8_t status=0; uint16_t ret=0; uint16_t freesize=0;

if (len > W5100.SSIZE) ret = W5100.SSIZE; // check size not to exceed MAX size. else ret = len;

Serial.print('$');

// if freebuf is available, start. int loopcnt=0; do { freesize = W5100.getTXFreeSize(s); status = W5100.readSnSR(s); if ((status != SnSR::ESTABLISHED) && (status != SnSR::CLOSE_WAIT)) { ret = 0; break; } loopcnt++; if (loopcnt==10) Serial.println("send.1"); } while (freesize < ret);

// copy data W5100.send_data_processing(s, (uint8_t *)buf, ret); W5100.execCmdSn(s, Sock_SEND);

/* +2008.01 bj / loopcnt=0; while ( (W5100.readSnIR(s) & SnIR::SEND_OK) != SnIR::SEND_OK ) { / m2008.01 [bj] : reduce code / if ( W5100.readSnSR(s) == SnSR::CLOSED ) { close(s); return 0; } loopcnt++; if (loopcnt==1000) { Serial.print("send.2, SnSR=0x"); Serial.print(W5100.readSnSR(s),HEX); Serial.print(", SnIR=0x"); Serial.print(W5100.readSnIR(s),HEX); Serial.print(", TX_WR=0x"); Serial.print(W5100.readSnTX_WR(s),HEX); Serial.print(", TX_RD=0x"); Serial.print(W5100.readSnTX_RD(s),HEX); Serial.println("."); close(s); return 0; } } / +2008.01 bj */ W5100.writeSnIR(s, SnIR::SEND_OK); return ret; }

The addition to the code is the loop counter in the second loop that detects the condition. It then prints out the values of various status registers which results in:

send.2, SnSR=0x17, SnIR=0x5, TX_WR=0x92A5, TX_RD=0x92A5.

Thus, it looks like everything is OK, except that the SEND bit is never signalled in the SnIR register: SnSR 0x17 = ESTABLISHED SnIR 0x5 = RECV|CON TX_WR==TX_RD indicates all data sent (I think??)

It seems that this may be an instance of the reported errata to the 5100 (see http://www.techw.co.jp/Download/3150A_5100_errata1_Eng.pdf )

Copied from original issue: arduino/Arduino#1049

[PaulStoffregen]

Here's a copy of the W5100 errata.