Hi,
I am doing my baby steps in ethernet communication. I am using Teensy 4.1 and QNEthernet library. I took an example which is named "BroadcastChat" in the library examples, I did not change anything in this code.
My initial hope was that I would be able to send text from serial monitor and receive it via Microsoft UDP Send/Receive app and the opposite way. That was my idea on testing (hardware is already tested, got my cables and everything else wired right)
However, after around 15 seconds after powering teensy up, I get the last line in the terminal '' Failed to get IP address from DHCP " I guess it is somehow related to the constant declared at the top of the code, but I dont know how exactly and I dont know what is cause of/how to solve it? Any ideas or observations?
// SPDX-FileCopyrightText: (c) 2023 Shawn Silverman <shawn@pobox.com>
// SPDX-License-Identifier: MIT
// BroadcastChat is a simple chat application that broadcasts and
// receives text messages over UDP.
//
// This file is part of the QNEthernet library.
#include <QNEthernet.h>
using namespace qindesign::network;
// --------------------------------------------------------------------------
// Configuration
// --------------------------------------------------------------------------
constexpr uint32_t kDHCPTimeout = 15'000; // 15 seconds
constexpr uint16_t kPort = 5190; // Chat port
// --------------------------------------------------------------------------
// Program State
// --------------------------------------------------------------------------
// UDP port.
EthernetUDP udp;
// --------------------------------------------------------------------------
// Main Program
// --------------------------------------------------------------------------
// Forward declarations (not really needed in the Arduino environment)
static void printPrompt();
static void receivePacket();
static void sendLine();
// Program setup.
void setup() {
Serial.begin(115200);
while (!Serial && millis() < 4000) {
// Wait for Serial
}
printf("Starting...\r\n");
uint8_t mac[6];
Ethernet.macAddress(mac); // This is informative; it retrieves, not sets
printf("MAC = %02x:%02x:%02x:%02x:%02x:%02x\r\n",
mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
Ethernet.onLinkState([](bool state) {
printf("[Ethernet] Link %s\r\n", state ? "ON" : "OFF");
});
printf("Starting Ethernet with DHCP...\r\n");
if (!Ethernet.begin()) {
printf("Failed to start Ethernet\r\n");
return;
}
if (!Ethernet.waitForLocalIP(kDHCPTimeout)) {
printf("Failed to get IP address from DHCP\r\n");
return;
}
IPAddress ip = Ethernet.localIP();
printf(" Local IP = %u.%u.%u.%u\r\n", ip[0], ip[1], ip[2], ip[3]);
ip = Ethernet.subnetMask();
printf(" Subnet mask = %u.%u.%u.%u\r\n", ip[0], ip[1], ip[2], ip[3]);
ip = Ethernet.broadcastIP();
printf(" Broadcast IP = %u.%u.%u.%u\r\n", ip[0], ip[1], ip[2], ip[3]);
ip = Ethernet.gatewayIP();
printf(" Gateway = %u.%u.%u.%u\r\n", ip[0], ip[1], ip[2], ip[3]);
ip = Ethernet.dnsServerIP();
printf(" DNS = %u.%u.%u.%u\r\n", ip[0], ip[1], ip[2], ip[3]);
// Start UDP listening on the port
udp.begin(kPort);
printPrompt();
}
// Main program loop.
void loop() {
receivePacket();
sendLine();
}
// --------------------------------------------------------------------------
// Internal Functions
// --------------------------------------------------------------------------
// Control character names.
static const String kCtrlNames[]{
"NUL", "SOH", "STX", "ETX", "EOT", "ENQ", "ACK", "BEL",
"BS", "HT", "LF", "VT", "FF", "CR", "SO", "SI",
"DLE", "DC1", "DC2", "DC3", "DC4", "NAK", "SYN", "ETB",
"CAN", "EM", "SUB", "ESC", "FS", "GS", "RS", "US",
};
// Receives and prints chat packets.
static void receivePacket() {
int size = udp.parsePacket();
if (size < 0) {
return;
}
// Get the packet data and remote address
const uint8_t *data = udp.data();
IPAddress ip = udp.remoteIP();
printf("[%u.%u.%u.%u][%d] ", ip[0], ip[1], ip[2], ip[3], size);
// Print each character
for (int i = 0; i < size; i++) {
uint8_t b = data[i];
if (b < 0x20) {
printf("<%s>", kCtrlNames[b].c_str());
} else if (b < 0x7f) {
putchar(data[i]);
} else {
printf("<%02xh>", data[i]);
}
}
printf("\r\n");
}
// Tries to read a line from the console and returns whether
// a complete line was read. This is CR/CRLF/LF EOL-aware.
static bool readLine(String &line) {
static bool inCR = false; // Keeps track of CR state
while (Serial.available() > 0) {
int c;
switch (c = Serial.read()) {
case '\r':
inCR = true;
return true;
case '\n':
if (inCR) {
// Ignore the LF
inCR = false;
break;
}
return true;
default:
if (c < 0) {
return false;
}
inCR = false;
line.append(static_cast<char>(c));
}
}
return false;
}
// Prints the chat prompt.
static void printPrompt() {
printf("chat> ");
fflush(stdout); // printf may be line-buffered, so ensure there's output
}
// Reads from the console and sends packets.
static void sendLine() {
static String line;
// Read from the console and send lines
if (readLine(line)) {
if (!udp.send(Ethernet.broadcastIP(), kPort,
reinterpret_cast<const uint8_t *>(line.c_str()),
line.length())) {
printf("[Error sending]\r\n");
}
line = "";
printPrompt();
}
}
