nRF9160DK and WINC1500 WiFi Module

[RodWatt]

Hi,

I am trying to get the Atmel WINC1500 module to work with the nRF9160DK.

I have read a similar post,

https://devzone.nordicsemi.com/f/nordic-q-a/76640/spi-issue-using-the-adafruit-winc1500-wifi-on-the-nrf9160dk/317289#317289

and have taken the advice to ensure I use pins that are not assigned to functions on the DK. My overlay file is this

&spi3 {
  compatible = "nordic,nrf-spim";
  status = "okay";
  cs-gpios = <&gpio0 10 GPIO_ACTIVE_LOW>;
  sck-pin = <0>;
  mosi-pin = <19>;
  miso-pin = <1>;

	winc1500@0 {
		status = "okay";
		compatible = "atmel,winc1500";
		reg = <0x0>;
		label = "winc1500";
		spi-max-frequency = <4000000>;
		irq-gpios = <&gpio0 16 GPIO_ACTIVE_LOW>;
		reset-gpios = <&gpio0 13 GPIO_ACTIVE_LOW>;
		enable-gpios = <&gpio0 12 0>;
	};
};

and my conf file is as follows.

CONFIG_GPIO=y

CONFIG_SPI=y

CONFIG_WIFI_WINC1500=y
CONFIG_WIFI_WINC1500_REGION_EUROPE=y

CONFIG_EARLY_CONSOLE=y

CONFIG_NETWORKING=y
#CONFIG_TEST_RANDOM_GENERATOR=y
CONFIG_NET_TX_STACK_SIZE=2048
CONFIG_NET_RX_STACK_SIZE=2048

CONFIG_NET_PKT_RX_COUNT=10
CONFIG_NET_PKT_TX_COUNT=10
CONFIG_NET_BUF_RX_COUNT=20
CONFIG_NET_BUF_TX_COUNT=20
CONFIG_NET_MAX_CONTEXTS=10

CONFIG_NET_IPV4=y
CONFIG_NET_IPV6=n

CONFIG_NET_TCP=y

CONFIG_NET_LOG=y
CONFIG_INIT_STACKS=y

CONFIG_NET_SHELL=y

CONFIG_NET_STATISTICS=y
CONFIG_NET_STATISTICS_PERIODIC_OUTPUT=n

CONFIG_WIFI=y

CONFIG_WIFI_LOG_LEVEL_ERR=y
CONFIG_NET_L2_WIFI_SHELL=y

 when I try to build the code, the is the code I'm using

https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/net/wifi

I get an error

Watt@Watt-Macbook-Pro WINC1500 % sh build_app.sh
[1/1] cd /Users/Watt/Documents/ZEPHYR_...ncs/v1.6.1/zephyr/cmake/pristine.cmake
-- Application: /Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500
-- Using NCS Toolchain 1.6.0 for building. (/opt/nordic/ncs/v1.6.0-rc2/toolchain/cmake)
-- Zephyr version: 2.6.0-rc1 (/opt/nordic/ncs/v1.6.1/zephyr), build: v2.6.0-rc1-ncs1
-- Found Python3: /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/python3 (found suitable exact version "3.8.2") found components: Interpreter 
-- Found west (found suitable version "0.11.0", minimum required is "0.7.1")
-- Board: nrf9160dk_nrf9160, Revision: 0.7.0
-- Cache files will be written to: /Users/Watt/Library/Caches/zephyr
-- Found dtc: /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/dtc (found suitable version "1.4.7", minimum required is "1.4.6")
-- Found toolchain: gnuarmemb (/opt/nordic/ncs/v1.6.0-rc2/toolchain)
-- Found BOARD.dts: /opt/nordic/ncs/v1.6.1/zephyr/boards/arm/nrf9160dk_nrf9160/nrf9160dk_nrf9160.dts
-- Found devicetree overlay: /Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500/nrf9160dk_nrf9160.overlay
-- Generated zephyr.dts: /Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500/build/zephyr/zephyr.dts
-- Generated devicetree_unfixed.h: /Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500/build/zephyr/include/generated/devicetree_unfixed.h
-- Generated device_extern.h: /Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500/build/zephyr/include/generated/device_extern.h
Parsing /opt/nordic/ncs/v1.6.1/zephyr/Kconfig
Loaded configuration '/opt/nordic/ncs/v1.6.1/zephyr/boards/arm/nrf9160dk_nrf9160/nrf9160dk_nrf9160_defconfig'
Merged configuration 'prj.conf'
Configuration saved to '/Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500/build/zephyr/.config'
Kconfig header saved to '/Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500/build/zephyr/include/generated/autoconf.h'
-- The C compiler identification is GNU 9.2.1
-- The CXX compiler identification is GNU 9.2.1
-- The ASM compiler identification is GNU
-- Found assembler: /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/arm-none-eabi-gcc
-- Configuring done
-- Generating done
-- Build files have been written to: /Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500/build
Make Complete

/Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500/build
[1/294] Preparing syscall dependency handling

[87/294] Building C object zephyr/CMak...fi/winc1500/wifi_winc1500_nm_bsp.c.obj
FAILED: zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500_nm_bsp.c.obj 
ccache /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/arm-none-eabi-gcc -DBUILD_VERSION=v2.6.0-rc1-ncs1 -DKERNEL -DNRF9160_XXAA -DUSE_PARTITION_MANAGER=0 -D_FORTIFY_SOURCE=2 -D__PROGRAM_START -D__ZEPHYR__=1 -I/opt/nordic/ncs/v1.6.1/zephyr/kernel/include -I/opt/nordic/ncs/v1.6.1/zephyr/arch/arm/include -I/opt/nordic/ncs/v1.6.1/zephyr/include -Izephyr/include/generated -I/opt/nordic/ncs/v1.6.1/zephyr/soc/arm/nordic_nrf/nrf91 -I/opt/nordic/ncs/v1.6.1/zephyr/lib/util/fnmatch/. -I/opt/nordic/ncs/v1.6.1/zephyr/drivers/wifi/winc1500/. -I/opt/nordic/ncs/v1.6.1/nrf/include -I/opt/nordic/ncs/v1.6.1/modules/hal/cmsis/CMSIS/Core/Include -I/opt/nordic/ncs/v1.6.1/modules/hal/nordic/nrfx -I/opt/nordic/ncs/v1.6.1/modules/hal/nordic/nrfx/drivers/include -I/opt/nordic/ncs/v1.6.1/modules/hal/nordic/nrfx/mdk -I/opt/nordic/ncs/v1.6.1/zephyr/modules/hal_nordic/nrfx/. -isystem /opt/nordic/ncs/v1.6.1/zephyr/lib/libc/minimal/include -isystem /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/../lib/gcc/arm-none-eabi/9.2.1/include -isystem /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/../lib/gcc/arm-none-eabi/9.2.1/include-fixed -isystem /opt/nordic/ncs/v1.6.1/nrfxlib/crypto/nrf_cc310_platform/include -Os -imacros /Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500/build/zephyr/include/generated/autoconf.h -ffreestanding -fno-common -g -fdiagnostics-color=always -mcpu=cortex-m33 -mthumb -mabi=aapcs -imacros /opt/nordic/ncs/v1.6.1/zephyr/include/toolchain/zephyr_stdint.h -Wall -Wformat -Wformat-security -Wno-format-zero-length -Wno-main -Wno-pointer-sign -Wpointer-arith -Wexpansion-to-defined -Wno-address-of-packed-member -Wno-unused-but-set-variable -Werror=implicit-int -fno-asynchronous-unwind-tables -fno-pie -fno-pic -fno-strict-overflow -fno-reorder-functions -fno-defer-pop -fmacro-prefix-map=/Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500=CMAKE_SOURCE_DIR -fmacro-prefix-map=/opt/nordic/ncs/v1.6.1/zephyr=ZEPHYR_BASE -fmacro-prefix-map=/opt/nordic/ncs/v1.6.1=WEST_TOPDIR -ffunction-sections -fdata-sections -std=c99 -nostdinc -MD -MT zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500_nm_bsp.c.obj -MF zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500_nm_bsp.c.obj.d -o zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500_nm_bsp.c.obj -c /opt/nordic/ncs/v1.6.1/zephyr/drivers/wifi/winc1500/wifi_winc1500_nm_bsp.c
In file included from /opt/nordic/ncs/v1.6.1/zephyr/drivers/wifi/winc1500/wifi_winc1500_nm_bsp.c:7:
/opt/nordic/ncs/v1.6.1/zephyr/drivers/wifi/winc1500/wifi_winc1500_nm_bsp_internal.h:15:10: fatal error: bus_wrapper/include/nm_bus_wrapper.h: No such file or directory
   15 | #include <bus_wrapper/include/nm_bus_wrapper.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
[88/294] Building C object zephyr/CMak...500/wifi_winc1500_nm_bus_wrapper.c.obj
FAILED: zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500_nm_bus_wrapper.c.obj 
ccache /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/arm-none-eabi-gcc -DBUILD_VERSION=v2.6.0-rc1-ncs1 -DKERNEL -DNRF9160_XXAA -DUSE_PARTITION_MANAGER=0 -D_FORTIFY_SOURCE=2 -D__PROGRAM_START -D__ZEPHYR__=1 -I/opt/nordic/ncs/v1.6.1/zephyr/kernel/include -I/opt/nordic/ncs/v1.6.1/zephyr/arch/arm/include -I/opt/nordic/ncs/v1.6.1/zephyr/include -Izephyr/include/generated -I/opt/nordic/ncs/v1.6.1/zephyr/soc/arm/nordic_nrf/nrf91 -I/opt/nordic/ncs/v1.6.1/zephyr/lib/util/fnmatch/. -I/opt/nordic/ncs/v1.6.1/zephyr/drivers/wifi/winc1500/. -I/opt/nordic/ncs/v1.6.1/nrf/include -I/opt/nordic/ncs/v1.6.1/modules/hal/cmsis/CMSIS/Core/Include -I/opt/nordic/ncs/v1.6.1/modules/hal/nordic/nrfx -I/opt/nordic/ncs/v1.6.1/modules/hal/nordic/nrfx/drivers/include -I/opt/nordic/ncs/v1.6.1/modules/hal/nordic/nrfx/mdk -I/opt/nordic/ncs/v1.6.1/zephyr/modules/hal_nordic/nrfx/. -isystem /opt/nordic/ncs/v1.6.1/zephyr/lib/libc/minimal/include -isystem /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/../lib/gcc/arm-none-eabi/9.2.1/include -isystem /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/../lib/gcc/arm-none-eabi/9.2.1/include-fixed -isystem /opt/nordic/ncs/v1.6.1/nrfxlib/crypto/nrf_cc310_platform/include -Os -imacros /Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500/build/zephyr/include/generated/autoconf.h -ffreestanding -fno-common -g -fdiagnostics-color=always -mcpu=cortex-m33 -mthumb -mabi=aapcs -imacros /opt/nordic/ncs/v1.6.1/zephyr/include/toolchain/zephyr_stdint.h -Wall -Wformat -Wformat-security -Wno-format-zero-length -Wno-main -Wno-pointer-sign -Wpointer-arith -Wexpansion-to-defined -Wno-address-of-packed-member -Wno-unused-but-set-variable -Werror=implicit-int -fno-asynchronous-unwind-tables -fno-pie -fno-pic -fno-strict-overflow -fno-reorder-functions -fno-defer-pop -fmacro-prefix-map=/Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500=CMAKE_SOURCE_DIR -fmacro-prefix-map=/opt/nordic/ncs/v1.6.1/zephyr=ZEPHYR_BASE -fmacro-prefix-map=/opt/nordic/ncs/v1.6.1=WEST_TOPDIR -ffunction-sections -fdata-sections -std=c99 -nostdinc -MD -MT zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500_nm_bus_wrapper.c.obj -MF zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500_nm_bus_wrapper.c.obj.d -o zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500_nm_bus_wrapper.c.obj -c /opt/nordic/ncs/v1.6.1/zephyr/drivers/wifi/winc1500/wifi_winc1500_nm_bus_wrapper.c
In file included from /opt/nordic/ncs/v1.6.1/zephyr/drivers/wifi/winc1500/wifi_winc1500_nm_bus_wrapper.c:19:
/opt/nordic/ncs/v1.6.1/zephyr/drivers/wifi/winc1500/wifi_winc1500_nm_bsp_internal.h:15:10: fatal error: bus_wrapper/include/nm_bus_wrapper.h: No such file or directory
   15 | #include <bus_wrapper/include/nm_bus_wrapper.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
[95/294] Building C object zephyr/CMak...vers/wifi/winc1500/wifi_winc1500.c.obj
FAILED: zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500.c.obj 
ccache /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/arm-none-eabi-gcc -DBUILD_VERSION=v2.6.0-rc1-ncs1 -DKERNEL -DNRF9160_XXAA -DUSE_PARTITION_MANAGER=0 -D_FORTIFY_SOURCE=2 -D__PROGRAM_START -D__ZEPHYR__=1 -I/opt/nordic/ncs/v1.6.1/zephyr/kernel/include -I/opt/nordic/ncs/v1.6.1/zephyr/arch/arm/include -I/opt/nordic/ncs/v1.6.1/zephyr/include -Izephyr/include/generated -I/opt/nordic/ncs/v1.6.1/zephyr/soc/arm/nordic_nrf/nrf91 -I/opt/nordic/ncs/v1.6.1/zephyr/lib/util/fnmatch/. -I/opt/nordic/ncs/v1.6.1/zephyr/drivers/wifi/winc1500/. -I/opt/nordic/ncs/v1.6.1/nrf/include -I/opt/nordic/ncs/v1.6.1/modules/hal/cmsis/CMSIS/Core/Include -I/opt/nordic/ncs/v1.6.1/modules/hal/nordic/nrfx -I/opt/nordic/ncs/v1.6.1/modules/hal/nordic/nrfx/drivers/include -I/opt/nordic/ncs/v1.6.1/modules/hal/nordic/nrfx/mdk -I/opt/nordic/ncs/v1.6.1/zephyr/modules/hal_nordic/nrfx/. -isystem /opt/nordic/ncs/v1.6.1/zephyr/lib/libc/minimal/include -isystem /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/../lib/gcc/arm-none-eabi/9.2.1/include -isystem /opt/nordic/ncs/v1.6.0-rc2/toolchain/bin/../lib/gcc/arm-none-eabi/9.2.1/include-fixed -isystem /opt/nordic/ncs/v1.6.1/nrfxlib/crypto/nrf_cc310_platform/include -Os -imacros /Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500/build/zephyr/include/generated/autoconf.h -ffreestanding -fno-common -g -fdiagnostics-color=always -mcpu=cortex-m33 -mthumb -mabi=aapcs -imacros /opt/nordic/ncs/v1.6.1/zephyr/include/toolchain/zephyr_stdint.h -Wall -Wformat -Wformat-security -Wno-format-zero-length -Wno-main -Wno-pointer-sign -Wpointer-arith -Wexpansion-to-defined -Wno-address-of-packed-member -Wno-unused-but-set-variable -Werror=implicit-int -fno-asynchronous-unwind-tables -fno-pie -fno-pic -fno-strict-overflow -fno-reorder-functions -fno-defer-pop -fmacro-prefix-map=/Users/Watt/Documents/ZEPHYR_Code/nRF9160DK/New_Code/WINC1500=CMAKE_SOURCE_DIR -fmacro-prefix-map=/opt/nordic/ncs/v1.6.1/zephyr=ZEPHYR_BASE -fmacro-prefix-map=/opt/nordic/ncs/v1.6.1=WEST_TOPDIR -ffunction-sections -fdata-sections -std=c99 -nostdinc -MD -MT zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500.c.obj -MF zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500.c.obj.d -o zephyr/CMakeFiles/zephyr.dir/drivers/wifi/winc1500/wifi_winc1500.c.obj -c /opt/nordic/ncs/v1.6.1/zephyr/drivers/wifi/winc1500/wifi_winc1500.c
/opt/nordic/ncs/v1.6.1/zephyr/drivers/wifi/winc1500/wifi_winc1500.c:37:10: fatal error: driver/include/m2m_wifi.h: No such file or directory
   37 | #include <driver/include/m2m_wifi.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
[96/294] Building C object zephyr/arch...ore__aarch32__cortex_m.dir/fault.c.obj
ninja: build stopped: subcommand failed.
Parsing hex file.
ERROR: The file specified could not be found.

This error can be avoided if I comment out the line

CONFIG_WIFI=y

This allows the code to build and run but of couse I then get an error saying there is no network.

uart:~$ *** Booting Zephyr OS build v2.6.0-rc1-ncs1  ***


[00:00:00.382,232] <err> net_if: There is no network interface to work with!
uart:~$ wifi scan
[00:00:06.206,115] <err> os: ***** USAGE FAULT *****
[00:00:06.206,115] <err> os:   Unaligned memory access
[00:00:06.206,115] <err> os: r0/a1:  0xaaaaaaaa  r1/a2:  0x00000000  r2/a3:  0x00000000
[00:00:06.206,146] <err> os: r3/a4:  0x20004c48 r12/ip:  0x00000000 r14/lr:  0x0000536d
[00:00:06.206,146] <err> os:  xpsr:  0x61000000
[00:00:06.206,146] <err> os: Faulting instruction address (r15/pc): 0x0000525c
[00:00:06.206,146] <err> os: >>> ZEPHYR FATAL ERROR 0: CPU exception on CPU 0
[00:00:06.206,176] <err> os: Current thread: 0x200005d8 (shell_uart)
*** Booting Zephyr OS build v2.6.0-rc1-ncs1  ***system


[00:00:00.251,525] <err> net_if: There is no network interface to work with!
uart:~$ 

Would appreciate your thoughts

Rod

[pirun lee]

Hi Rod,

The message is just warning. It is caused by this Kconfig.

config WINC1500_DRV_USE_OLD_SPI_SW
	bool "Use old SPI access method in the vendor HAL"
	help
	  This option, when enabled, causes USE_OLD_SPI_SW
	  setting to be passed to vendor HAL.

You can't generate zephyr.hex if there is any compile time error.

Can you use logic analyze to observe SPI communication?

[pirun lee]

HI Rod,

We can learn SPI master is sending correct signal from your capture while not connecting WINC1500.

SPIM is trying to reset module.

#define CMD_RESET				0xcf

	case CMD_RESET:							/* reset */
		bc[1] = 0xff;
		bc[2] = 0xff;
		bc[3] = 0xff;
		len = 5;
		break;

However you can't get anything when WINC1500 connected.

It seems that bus has been pulled down by WINC1500.

I would suggest that you check the power sequence of WINC1500.

[RodWatt]

Hi Pirun,

I have connected the reset signal and can see that its high. I am basing my overlay file on this example.

https://github.com/zephyrproject-rtos/zephyr/blob/main/samples/net/wifi/boards/reel_board.overlay

my overlay file is this

&spi3 {
  compatible = "nordic,nrf-spim";
  status = "ok";
  cs-gpios = <&gpio0 18 GPIO_ACTIVE_LOW>;
  sck-pin = <0>;
  mosi-pin = <19>;
  miso-pin = <1>;

	winc1500@0 {
		status = "ok";
		compatible = "atmel,winc1500";
		reg = <0x0>;
		label = "winc1500";
		spi-max-frequency = <4000000>;
		irq-gpios = <&gpio0 16 1>;
		reset-gpios = <&gpio0 13 1>;
		enable-gpios = <&gpio0 12 0>;

//		irq-gpios = <&gpio0 16 GPIO_ACTIVE_HIGH>;
//		reset-gpios = <&gpio0 13 GPIO_ACTIVE_HIGH>;
//		enable-gpios = <&gpio0 12 GPIO_ACTIVE_LOW>;
	};
};

Im assuming that the power up sequence is handled by the driver, I just need to connect the right signals, which I believe I have.

Rod

[helsing]

Hi Rod, sorry for the long delay.

How are you supplying the WiFi module? What are the IO voltages on the WiFi module and nRF9160 DK? Are they both configured to communicate at a corresponding level?

If you could share the schematics showing the SPI setup we could take a look. 

Best regards, 

Håkon

[RodWatt]

Hi Håkon,

No problem, I understand that things take longer during vacation time.

I am using this module.

https://www.microchip.com/content/dam/mchp/documents/OTH/ProductDocuments/UserGuides/50002616A.pdf

Pin	    Signal	    nRF9160DK Connection
1	    ID_DATA	        -
2	    GND	            0V
3	    NC	            -
4	    NC	            -
5	    RESET_N	        P0.13
6	    WAKE	        +3.3V
7	    NC	            -
8	    NC	            -
9	    IRQN	        P0.16
10	    CHIP_EN	        P0.12
11	    I2C_SDA	        -
12	    I2C_SCK	        -
13	    UART_RX	        -
14	    UART_TX	        -
15	    SPI_SSN	        P0.18
16	    SPI_MOSI	    P0.19
17	    SPI_MISO	    P0.01
18	    SPI_SCK	        P0.00
19	    GND	            0V
20	    VCC	            +3.3V

You will see my overlay file in a previous comment.

I am using the NRF9160DK, with the I/o set to 3V.

Rod

[helsing]

Hi Rod, 

Thank you for providing the details. So far I have only had a quick look. The first thing I stumbled into is this comment in the ATWINC1500B-IMU datasheet regarding the Wake pin:

Where at the DK is this pin connected? Is it connected to 3.0V or to 3.3V? What happens if you leave it unconnected?

Best regards, 

Håkon

[RodWatt]

Hi Håkon,

Yes, I had seen that and have tried various connections, +3V, unconnected and even 0V to see if I can see a change in behaviour. It didn't seem to change anything. 

uart:~$ wifi scan
Scan request failed
[00:00:13.617,279] <err> wifi_winc1500: Failed to request scan
uart:~$

Rod