updated readme

Signed-off-by: Richard Lemon <[email protected]>

apps/lwip/README.md

@@ -0,0 +1,31 @@
+# LWIP app
+
+LWIP echo server with any luck, based off the picoserver
+
+## Troubleshooting
+
+### ping doesn't work
+
+Try ```arpping```
+
+```bash
+arpping -i eth0 192.168.168.2
+```
+
+You should see many packets going back and forth
+
+If there are none check that you are servicing lwip in your timer interrupt.
+
+### arp ping only returns one packet
+
+```bash
+arpping -i eth0 192.168.168.2
+```
+
+try pinging broadcast
+
+```bash
+arpping -b -i eth0 192.168.168.2
+```
+
+if this works it is likely you have different mac addresses for your hardware and lwip stack.