Synopsis

Minimal REST API demo for TI's CC3200 WiFi chip (on development board) with instructions for compiling and debugging on Linux.

Usage

Build instructions on Linux systems

1. Setup path to CC3200 SDK as documented in the Linux Setup section below
2. Build http-server.axf

   mkdir build && cd build
   cmake .. -DCMAKE_TOOLCHAIN_FILE=../toolchain.cmake
   make

   You may need to run the toolchain and build twice due to an ongoing problem in cmake instructions.
3. Run using gdb

   arm-none-eabi-gdb -x $CC3200SDK/tools/gcc_scripts/gdbinit http-serve.axf

4. The board will start in AP mode with SSID Wifi Demo (open)
5. Connect to the chip
6. Send GET and POST in the Wifi Demo API section

Wifi Demo API

Server: 192.168.1.1 (wifidemo.com) Port: 5001

/led

GET

Return Status of the three LED lights (red, green, and orange) as a JSON object.

Method: GET Path: /led

Example request:

curl 192.168.1.1:5001/led

Example response:

200 OK HTTP/1.0
Content-Length: 45
Content-Type: application/json
{"orange": "off","green": "off","red": "off"}

POST

Toggle LED lights on or off.

Method: POST Path: /led Content-Type: application/json

Must specify Content-Length. Server may respond with 411 or 415 if an invalid content-length or content-type, respectively, is specified.

Example request:

curl -H "Content-Type: application/json" -X POST -d \
    "{\"green\": \"on\", \"orange\": \"on\", \"red\": \"on\"}" 192.168.1.1:5001/led
curl -H "Content-Type: application/json" -X POST -d \
    "{\"green\": \"on\"}" 192.168.1.1:5001/led
curl -H "Content-Type: application/json" -X POST -d \
    "{\"red\": \"on\", \"green\": \"off\"}" 192.168.1.1:5001/led

Example response:

204 No Content HTTP/1.0

Linux Setup

Systems used

I used following systems for compiling and initial development:

• Fedora 24 (4.11.12-100.fc24.x86_64)
• OpenSUSE Tumbleweed (4.12.8-1-default (4d7933a) x86_64)
  • installed packages (described below)
    • libncurses5-32bit
    • openocd (dependencies: libftdi1-2 libhidapi-hidraw0 libjaylink libjaylink0 libjim0_75 libusb-0_1-4 openocd openocd-data libjaylink)
    • libusb-1_0-devel
• CC3200SDK v1.3.0
• gcc-arm-none-eabi 5.4 2016 q3

Instructions

1. Download CC3200 SDK

• Download from TI website https://www.ti.com/tool/cc3200sdk verison 1.3.0 was used at the time of this writing
• Run installer (ran under a Windows machine) and copy the installed directory. All required files are bundled in the installed directory)
• Copy content to /path/to/directory/goes/here. For convenience, assign a variable to this path:

  echo export CC3200SDK=/path/to/directory/goes/here >> ~.bashrc

  and reload your .bashrc:

  . ~/.bashrc

2. Configure LaunchXL JTAG Debug interface

• Load ftdi-sio module

  modprobe ftdi-sio
  echo 0451 c32a > /sys/bus/usb-serial/drivers/ftdi_sio/new_id

• If running an old kernel, syntax will be different; see references above

3. Build and Install openocd

• Fedora/CentOS

  yum install libusb-devel

• OpenSUSE

  zypper in libusb-1_0-devel

• OpenOCD comes in default OpenSUSE repos:

  zypper in openocd

For OpenSUSE go to next step. For Fedora: download openocd, extract, and cd into it then

./configure

Make sure configure reports MPSSE mode of FTDI based devices yes (auto). Then build:

make -j 4
make install
sed -i s/plugdev/YOUR_GROUP_NAME_GOES_HERE/g contrib/60-openocd.rules
cp openocd/contrib/60-openocd.rules /etc/udev/rules.d/

(Note: rules do not affect devices that are already plugged in. If the Launchpad was plugged in, unplug and replug it to take effect)

• Make sure openocd runs

  openocd -f $CC3200SDK/tools/gcc_scripts/cc3200.cfg

  Press C-c to exit

4. Install cross tool chain

• In Fedora, tool chain is available in the official repos:

yum install arm-none-eabi arm-none-eabi-newlib arm-none-eabi-gdb

For OpenSUSE, build or download the prebuilt toolchain binaries (https://launchpad.net/gcc-arm-embedded/+download) and put the binaries in path, e.g.

echo export PATH=$PATH:/opt/gcc-arm-none-eabi-5_4-2016q3/bin/ >> ~.bashrc

and reload .bashrc

• Edit $CC3200SDK/tools/gcc_scripts/gdbinit to make sure OpenOCD finds its configuration file:

  target remote | openocd -c "gdb_port pipe; log_output openocd.log" -f $CC3200SDK/tools/gcc_scripts/cc3200.cfg

Flashing

cc3200tool can be used for flashing and downloading files. Its README is self-explanatory.

Compile and Run Examples

Example 1

Building $CC3200SDK/example/blinky

• Jumpers need to be set correctly, see Figure 1 in the Getting_Started_Guide.pdf document

cd $CC3200SDK/example/blinky/gcc
make

• Run a GDB session with the built file

arm-none-eabi-gdb -x $CC3200SDK/tools/gcc_scripts/gdbinit exe/blinky.axf

Alternatively, you may consider adding this alias to your .bashrc:

echo alias gdb-cc3200='arm-none-eabi-gdb -x $CC3200SDK/tools/gcc_scripts/gdbinit' >> ~.bashrc

and starting the debugger with

gdb-cc3200 exe/blinky.axf

• Press c and enter to continue executing the main function

Example 2

Building $CC3200SDK/example/getting_started_with_wlan_ap

This example requires input from the user, which is written to a tty

• Jumpers need to be set correctly, and board must be in AP Mode. See /docs/example/ documents

• Build the application

  cd $CC3200SDK/example/getting_started_with_wlan_ap/gcc
  make

  Concatenate USB0 tty (keep it running)

  cat /dev/ttyUSB0

  This of courses assumes that you have a single /dev/ttyUSB0 corresponding to the development board.

• Run a GDB session with the built file in a separate terminal

  arm-none-eabi-gdb -x ~/cc3200-sdk/tools/gcc_scripts/gdbinit exe/wlan_ap.axf

  and press c to continue

• Open another terminal and send in the SSID when requested:

  echo "this is my ssid" > /dev/ttyUSB0

Alternatively, instead of cating the controlling terminal, you can use screen:

• Get the baudrate of the tty

stty < /dev/ttyUSB0

• Open screen

screen /dev/ttyUSB0 insert_baudrate_here

and replace insert_baudrate_here with the actual baudrate

Example 3

Building $CC3200SDK/example/tcp_socket

This example shows how to run the tcp_socket example with only the tools that come shipped with every distro.

Sending packets

• Overwrite SSID_NAME, SECURITY_TYPE, and SECURITY_KEY in main.c with the information from your router

• Build the application

  cd $CC3200SDK/example/tcp_socket/gcc
  make

• Concatenate USB0 FIFO (keep it running)

  cat /dev/ttyUSB0

• Run a GDB session with the built file in a separate terminal

  arm-none-eabi-gdb -x ~/cc3200-sdk/tools/gcc_scripts/gdbinit exe/tcp_socket.axf

  and press c to continue

• Follow as in previous example to make selections in prompted options. Make following changes:

  • Packet size: 10

  This change is made to make the example complete quicker when manually sending packets

• Navigate the menus and make CC3200 listen for packets

• Start a telnet connection to the CC3200

  telnet <LOCAL_IP_ADDRESS_OF_CC3200> 5001

  and start typing random strings followed by enter. Repeat 10 times.

Receiving packets:

• Follow as in previous example and make following selections:
  • Packet size: 10
  • Destination IP: Local IP address of your computer
  • Port: 5001
• Start a server on your local machine

  nc -vl <LOCAL_COMPUTER_IP_ADDRESS> 5001

• Navigate the menus on CC3200 and set it to send packets to server (your computer)

Reference

1. http://azug.minpet.unibas.ch/~lukas/bricol/ti_simplelink/CC3200-LaunchXL.html
2. https://community.particle.io/t/cc3200-network-processor-information-station/5348/59
3. https://hackpad.com/Using-the-CC3200-Launchpad-Under-Linux-Rrol11xo7NQ