Unable to initialize W5100 using Arduino Pro Mini I am unable to initialize a W5100 module using an Arduino Pro Mini. I try setting the MAC and IP addresses but read invalid values thereafter.

Here is the Arduino program along with the output:

void setup() {
    uint8_t mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
    uint8_t local_ip[] = {192, 168, 1, 100};
    Ethernet.begin(mac, local_ip);
    printMacAddress(); // OUTPUT: FF:FF:FF:FF:FF:FF
    printIpAddress(); // OUTPUT: 255.255.255.255
}

void printMacAddress() {
    uint8_t mac[6];
    W5100.getMACAddress(mac);
    Serial.print(mac[0], HEX); Serial.print(":"); Serial.print(mac[1], HEX); Serial.print(":");
    Serial.print(mac[2], HEX); Serial.print(":"); Serial.print(mac[3], HEX); Serial.print(":");
    Serial.print(mac[4], HEX); Serial.print(":"); Serial.print(mac[5], HEX); Serial.println();
}

void printIpAddress() {
    IPAddress ip = Ethernet.localIP();
    Serial.println(ip);
}


I read in some blog posts that the Arduino may initialize before the W5100 initialization is completed so others recommend manually resetting the W5100 after Arduino initialization.
So I connected the W5100 reset pin to the Arduino digital output 4 and reset the W5100 during setup using the following code.

const int W5100_RESET_PIN = 4;
pinMode(W5100_RESET_PIN, OUTPUT);
digitalWrite(W5100_RESET_PIN, LOW); // Activate reset pin by asserting low
delay(5); // Wait for 5 msec
digitalWrite(W5100_RESET_PIN, HIGH); // Deactivate reset pin by asserting high
delay(300); // Wait for W5100 to initialize[/code]


I observed the W5100 resetting because the module LEDs flashed off and back on each time I manually reset the Arduino. However this does not fix the W5100 mac/IP initialization issue.

How should I troubleshoot this issue?

Here are pictures of the assembly.
https://imgur.com/a/h4TWx

Here is an overview of the W5100 module.
http://arduino-info.wikispaces.com/Ethernet
One of the Ethernet examples shows you should test the result of the begin function call, like this:

// start the Ethernet connection:
  if (Ethernet.begin(mac) == 0) {
    Serial.println("Failed to configure Ethernet using DHCP");
    // try to congifure using IP address instead of DHCP:
    Ethernet.begin(mac, ip);
  }


Try displaying the return value from begin to see if that initialization succeeded.