Arduino 101 + Wifi 101 Shield - Hang on scan networks (SOLVED)

Hardware WiFi Shield 101
1

I have an Arduino 101 and purchased a 2 Wifi 101 shields, but have been unable to successfully run the example sketches on either.

When attempting to run the Wifi101 ScanNetworks example sketch, it hangs at the following location:

// scan for nearby networks:
Serial.println("** Scan Networks **"); <-- Last line I see. This doesn't repeat.
int numSsid = WiFi.scanNetworks();
Serial.println("Does not get printed");

I am also unable to run the Wifi101 ConnectWithWPA sketch (I did use the correct SSID and password):

Serial.print("Attempting to connect to WPA SSID: ");
Serial.println(ssid); <-- Last line I see
// Connect to WPA/WPA2 network:
status = WiFi.begin(ssid, pass);
Serial.println("Does not get printed");

EDIT: I've done some digging, and discovered that WiFiClass:scanNetworks() (among other functions) hangs. For startNetworks(), it locks up the Arduino in m2m_hif.c's hif_send() function:

reg = dma_addr << 2;
reg |= (1 << 1);
ret = nm_write_reg(WIFI_HOST_RCV_CTRL_3, reg); <-- Hangs if this line executes.
if(M2M_SUCCESS != ret) goto ERR1;

I am able to run the CheckWifi101FirmwareVersion sketch. This reports I am at the required version (19.4.4).

I was unable to use the latest library, 0.9.0, as it doesn't compile, so I used/tried previous versions (0.8.0, 0.7.0) with no success.

In case it matters, I have the latest (1.0.5) Curie board library and Arduino IDE 1.6.8.

Has anyone encountered this or something similar?

2

OK. So, the issue is solved (at least for me). It ended up being an under-power issue (I was powering the Arduino via USB ports). Choosing a different port allowed me to run the scanNetworks example.

Going with a wall wart is probably the way to go, just to be safe.

The bug I filed (before I knew what was going on) and the gory details of the debug can be found here:

Hope this helps someone with the same issue!