Version: 1.0 Release date: 1 st December 2015 Specifications are subject to change without notice. 2015 MediaTek Inc. Unauthorized reproduction of this information in whole or in part is strictly prohibited.
Document Revision History Revision Date Description 1.0 1 st Dec 2015 Initial release 2015 MediaTek Inc. Page 2 of 15
Table of Contents 1. Introduction... 5 2. About the development platform... 6 2.1. What is the MediaTek LinkIt Smart 7688 development platform?... 6 2.2. What s the difference between the LinkIt Smart 7688/7688 Duo development boards?... 6 2.3. What is MediaTek MT7688AN?... 6 2.4. What do I need to start using the LinkIt Smart 7688 development board?... 6 2.5. What can I develop using the LinkIt Smart 7688 development platform?... 7 2.6. Where can I download the LinkIt Smart 7688 SDT?... 7 2.7. Should I backup my data before upgrading the firmware?... 7 2.8. Is Smart Connection supported on the LinkIt Smart 7688 development platform?... 7 2.9. Is HomeKit supported on the LinkIt Smart 7688 development platform?... 7 2.10. What is the MediaTek AP SOC SDK?... 7 2.11. Is ecos supported on the LinkIt Smart 7688 development platform?... 7 2.12. What do the LED (Wi-Fi) blinks represent?... 7 2.13. Why does the LinkIt Smart 7688 Duo COM port change frequently in Arduino IDE 1.6.5?... 7 2.14. What s MT7688AN s IoT device and gateway mode?... 8 2.15. What s the difference between MT7688AN and MT7688A?... 8 2.16. What s MT7688KN and how is it different from MT7688AN?... 8 2.17. What s MT7620 and how is it different from MT7688AN?... 8 2.18. What s MT7628 and how is it different from MT7688AN?... 8 3. Hardware features... 9 3.1. What I/O ports do the LinkIt Smart 7688/7688Duo development boards provide?... 9 3.2. What is the power consumption of the LinkIt Smart 7688 development boards?... 9 3.3. Can I use SD Card to boot up the board?... 9 3.4. Does the LinkIt Smart 7688 development platform support hardware AES?... 9 3.5. What is Wi-Fi AP and Station mode?... 9 3.6. Can the LinkIt Smart 7688 development board support both AP and Station mode at the same time?... 9 3.7. How do I switch between AP and Station modes?... 9 3.8. How to find LinkIt Smart 7688 development board s IP address when it s in Station mode?... 10 3.9. Is the Wi-Fi driver open source?... 10 4. Software development... 11 4.1. Where can I get the system firmware and boot loader source code?... 11 4.2. What programming languages and environment can I use to develop applications for LinkIt Smart 7688?... 11 4.3. Can I program in C/C++? Are there any limitations?... 11 4.4. What are UPM and MRAA?... 11 4.5. What is Firmata?... 11 4.6. What is Bridge Library?... 11 4.7. How often can I write to the internal flash of the microcontroller?... 12 5. Hardware development... 13 5.1. Can I design my own hardware to use LinkIt?... 13 5.2. What is Ralink?... 13 5.3. How do I upgrade the firmware?... 13 5.4. How do I use a USB drive to flash firmware to the LinkIt Smart 7688 development board?... 13 6. Purchasing the LinkIt Smart 7688 development board... 14 6.1. Where can I purchase the LinkIt Smart 7688 HDK?... 14 2015 MediaTek Inc. Page 3 of 15
7. Going to market with LinkIt Smart 7688 based IoT device... 15 7.1. How do I get my LinkIt devices to market?... 15 7.2. Where can I find more information or help on issues I encounter during development?... 15 2015 MediaTek Inc. Page 4 of 15
1. Introduction This document provides answers to many of the questions developer frequently ask about the MediaTek LinkIt Smart 7688 developer platform. The questions and answers are presented in the following categories: About the development platform Hardware features Software development Hardware development Purchasing the LinkIt Smart 7688 development board and module Going to market with a LinkIt Smart 7688 based IoT device 2015 MediaTek Inc. Page 5 of 15
2. About the development platform 2.1. What is the MediaTek LinkIt Smart 7688 development platform? LinkIt Smart 7688 is a Linux, Wi-Fi, SOC, open development platform based on the OpenWrt Linux distribution designed to enable the prototyping of IoT devices. These devices include Wi-Fi security web cam and sensors for the home or office, real time camera monitor for toddler and seniors as well as cloud-based applications. LinkIt Smart 7688 provides generous memory and storage to enable rich application developments. The platform also offers options to create device applications using Python, Node.js or C. 2.2. What s the difference between the LinkIt Smart 7688/7688 Duo development boards? Both development boards run the OpenWrt operating system and provide the same development environment. The difference is in the peripheral controls such as GPIO, I2C, SPI, PWM etc. On the LinkIt Smart 7688 board, the I/O pins are broken out from MT7688AN directly. But on the LinkIt Smart 7688 Duo board, the I/O functions are broken out from the MCU for better real time control. This allows developers to use Arduino development environment to control the MCU in addition to using physical pin to establish communication between the MT7688AN and the MCU. For more details, please refer to Chapter 6 "Peripheral Programming on LinkIt Smart 7688 Duo" of the LinkIt Smart 7688 Developers' Guide. 2.3. What is MediaTek MT7688AN? MediaTek MT7688AN is a highly integrated SOC with 1T1R 802.11 b/g/n Wi-Fi radio, a 575/580MHz MIPS 24KEcTM CPU, 1-port fast Ethernet PHY, USB2.0 host, PCIe, SD-XC, I2S/PCM and multiple low-speed Inputs and Outputs such as GPIO, I2C, SPI, PWM etc. For more details, please refer to the MT7688AN datasheet. 2.4. What do I need to start using the LinkIt Smart 7688 development board? The main devices and accessories are described as follows: Main devices: 1) A laptop or smartphone with Wi-Fi connectivity. You ll use this device to connect to LinkIt Smart 7688 for board configuration. 2) A micro-usb type-b cable with a USB power source to provide power to the board. 3) A Wi-Fi network. This is to provide Internet access to the board. In addition to the main devices, it s recommended to use a micro SD card to expand the on-board flash storage. This is because the on-board flash has limited storage and write-cycle. Accessories: 1) An OTG (On the Go) cable. This connects devices with USB Type A connector to the LinkIt Smart 7688 board's USB host (micro B type). 2) A USB drive. You can use this device to upgrade the system firmware and boot loader directly. 3) A UART to USB cable. This device is used to access the Linux console. 2015 MediaTek Inc. Page 6 of 15
2.5. What can I develop using the LinkIt Smart 7688 development platform? LinkIt Smart 7688 is basically a Linux computer with Wi-Fi connectivity. With the OpenWrt Linux distribution and the support of programming languages such as Python, Node.js, and C, you can create applications including but not limited to gateways, communication bridges, video streaming, and home automation. 2.6. Where can I download the LinkIt Smart 7688 SDT? You can download the latest SDT from the MediaTek Labs' website (labs.mediatek.com/7688) 2.7. Should I backup my data before upgrading the firmware? Yes and it s highly recommended because all user data and system configuration will be erased from the device when performing a firmware upgrade. 2.8. Is Smart Connection supported on the LinkIt Smart 7688 development platform? No. The Smart Connection feature isn t included in the OpenWrt release used by LinkIt Smart 7688. If you would like to get more information about Smart Connection, please contact the MediaTek Labs Partner Connect Program. 2.9. Is HomeKit supported on the LinkIt Smart 7688 development platform? No. The HomeKit feature isn t included in the OpenWrt release used by LinkIt Smart 7688. If you would like to get more information about HomeKit, please contact the MediaTek Labs Partner Connect Program. 2.10. What is the MediaTek AP SOC SDK? The MediaTek AP SOC SDK is a Linux distribution used for the MediaTek MT76xx series and is maintained by MediaTek. LinkIt Smart 7688 uses OpenWrt which provides a newer and standardized Linux kernel. 2.11. Is ecos supported on the LinkIt Smart 7688 development platform? No. LinkIt Smart 7688 runs OpenWrt. To use MT7688AN with ecos, please contact MediaTek Labs Partner Connect Program for more information. 2.12. What do the LED (Wi-Fi) blinks represent? The Wi-Fi LED represents the status of the board including system initialization, firmware upgrade, Wi-Fi connection mode and status. For more details on the LED status, please refer to Figure 15 "Wi-Fi LED Status" and Section 2.2.3 "LEDs" from the LinkIt Smart 7688 Developer's Guide. 2.13. Why does the LinkIt Smart 7688 Duo COM port change frequently in Arduino IDE 1.6.5? This is a known issue when using Arduino IDE 1.6.5. This issue is also discussed in https://github.com/arduino/arduino/issues/3495#issuecomment-153663216 You can use Arduino IDE 1.6.4 to avoid this issue, or program a new version of the Arduino boot loader. Please refer to Section 6.6.8, 6.6.9 or 6.6.10 to program the boot loader from the LinkIt Smart 7688 Developer's Guide for more details. 2015 MediaTek Inc. Page 7 of 15
2.14. What s MT7688AN s IoT device and gateway mode? The MT7688AN chipset acts as a 5-port Wi-Fi gateway when it s in gateway mode. Since LinkIt Smart 7688 runs in IoT device mode, MT7688AN is switched to device mode to enable the peripheral I/O pins which are shared with the 5-port Ethernet pins used in the gateway mode. 2.15. What s the difference between MT7688AN and MT7688A? They are the same. MT7688AN is the formal name used in the chipset s datasheet. 2.16. What s MT7688KN and how is it different from MT7688AN? MT7688KN has different package from MT7688AN. MT7688KN package contains 8MB DDR1 DRAM and doesn t support SD card for entry-level router application. For more details, please refer to the MT7688AN datasheet. 2.17. What s MT7620 and how is it different from MT7688AN? MT7628 is the successor of MT7620. It provides more peripheral I/O types and is more energy efficient than MT7620. 2.18. What s MT7628 and how is it different from MT7688AN? The MT7628 series are pin-to-pin compatible with the MT7688 series. However, MT7628 comes with a 2T2R antenna, while MT7688 only supports 1T1R antenna. 2015 MediaTek Inc. Page 8 of 15
3. Hardware features 3.1. What I/O ports do the LinkIt Smart 7688/7688Duo development boards provide? Both development boards provide Ethernet, USB Host, micro SD, I2C, PWM, SPI, GPIO, and UART. In addition, the LinkIt Smart 7688 board also provides I2S while the LinkIt Smart 7688 Duo board provides ADC. 3.2. What is the power consumption of the LinkIt Smart 7688 development boards? Please refer to Section 2.2.6 "USB Power" from the LinkIt Smart 7688 Developer's Guide for detailed power consumption information. 3.3. Can I use SD Card to boot up the board? No. MT7688AN doesn't support boot up from a SD card. 3.4. Does the LinkIt Smart 7688 development platform support hardware AES? Yes. The Wi-Fi driver uses hardware AES engine for data transmission. 3.5. What is Wi-Fi AP and Station mode? When the LinkIt Smart 7688 development board is in AP mode, it acts as an AP which allows other devices to connect to it through Wi-Fi. Use Wi-Fi to connect to the board for initial setup and configuration. When the board is in Station mode, it acts as a Wi-Fi client device which can connect to an existing AP to access external network such as the Internet. 3.6. Can the LinkIt Smart 7688 development board support both AP and Station mode at the same time? No. LinkIt Smart 7688 development boards can only be in either AP or Station mode at a time. 3.7. How do I switch between AP and Station modes? There are two ways to switch between the AP and Station modes on LinkIt Smart 7688 development board and they are: 1) From the Web UI. 2) Through the OpenWrt UCI commands. Please refer to Section 4.6.5 "Connecting LinkIt Smart 7688 to a Wi-Fi Access Point to Access the Internet" from the LinkIt Smart 7688 Developer s Guide for more details. 2015 MediaTek Inc. Page 9 of 15
3.8. How to find LinkIt Smart 7688 development board s IP address when it s in Station mode? The steps to find the board s IP address are: 3) Make sure your host PC is within the same network as the development board. 4) Make sure your host PC supports mdns. Please refer to Section 4.5.2 "Local Domain" of the LinkIt Smart 7688 Developer's Guide for more details. 5) Open a terminal console and type "ping mylinkit.local" and you ll see the IP address of the development board. 3.9. Is the Wi-Fi driver open source? The MAC802.11 implementation for MT7688AN open source Wi-Fi driver is under development. Only binary Wi-Fi driver is released at the time of writing. 2015 MediaTek Inc. Page 10 of 15
4. Software development 4.1. Where can I get the system firmware and boot loader source code? For the system firmware source code, please refer to: https://github.com/mediatek-labs/linkit-smart-7688- feed For the boot loader source code, please refer to: https://github.com/mediatek-labs/linkit-smart-7688-uboot 4.2. What programming languages and environment can I use to develop applications for LinkIt Smart 7688? You can use Python, Node.js, and C languages to develop your programs or applications on LinkIt Smart 7688. To compile the C programs, you need to cross compile under a Linux or Mac OS X environment. Windows isn t supported by the current tool chain, therefore a virtual machine needs to be installed on a Windows platform for C program cross compilations. 4.3. Can I program in C/C++? Are there any limitations? Yes you can program in C/C++. For Windows operating system users, you need to install a virtual machine to run the cross compile toolchain, which only supports Linux and Mac OS X at the time of writing. 4.4. What are UPM and MRAA? MRAA is an open source project which provides C/C++ library with bindings to Python and Node.js to interface with the I/O on Linux platforms. It supports structured and sane API where port names/numbers match the board that you are using. UPM is a repository that holds collections of sensor and module drivers written in MRAA. You can refer to the below official project pages for more details: http://iotdk.intel.com/docs/master/mraa/ http://iotdk.intel.com/docs/master/upm/ 4.5. What is Firmata? Firmata is a communication protocol between a MCU and a MPU. Many Firmata implementations have been used to date due to its flexibility. Therefore, developers who are familiar with MPU programming in Python, Node.js or C can choose a language they prefer to use Firmata to run the communication between a MPU and a MCU without having to deal with details of the UART command implementation and programming on the MCU side. 4.6. What is Bridge Library? Bridge Library is the mechanism used in Arduino Yun for communication between a MPU and a MCU. LinkIt Smart 7688 Duo supports Arduino Yun Bridge library implementation to enable developers build their projects in the way they re familiar with. For more details about Bridge Library, please refer to https://www.arduino.cc/en/reference/yunbridgelibrary 2015 MediaTek Inc. Page 11 of 15
4.7. How often can I write to the internal flash of the microcontroller? It s not recommended to write to the flash too frequently because NOR flash doesn t have wear leveling MTD layer, atomic I/O operation and has limited re-write life time (about 100,000). 2015 MediaTek Inc. Page 12 of 15
5. Hardware development 5.1. Can I design my own hardware to use LinkIt? Yes, the schematic and layout design for the development board and module are available for download as part of the LinkIt Smart 7688 Hardware Reference Design. You can also find a datasheets for the chipsets on the LinkIt Smart 7688 Documentation page. 5.2. What is Ralink? Ralink Technology was a Wi-Fi chipset provider that was acquired by MediaTek in 2011. The MT76xx series inherit some architecture from Ralink's RT2xxx/RT3xxx series. 5.3. How do I upgrade the firmware? You can download the latest firmware from MediaTek Labs' website and use the LinkIt Smart 7688 Web UI or a USB drive to upgrade the firmware. For more details, please refer to Section 4.6.1 "Upgrading Firmware" from the LinkIt Smart 7688 Developer's Guide. 5.4. How do I use a USB drive to flash firmware to the LinkIt Smart 7688 development board? The steps to flash firmware on the LinkIt Smart 7688 development board are: 1) Save the firmware file (lks7688.img) to the root directory of a USB drive. You can download the latest firmware from MediaTek Labs website. 2) Plug the USB drive to the development board. 3) Press the Wi-Fi and MPU (Reset) button, then release the MPU Reset button only but hold the Wi-Fi button for at least 5 seconds and release when the Wi-Fi LED turns off, see below figure for detailed LED status. Do not press the Wi-Fi button for longer than 20s or the development board will enter boot loader mode and erase all user data. Flash Firmware From USB Drive Press Release Wi-Fi Reset Button MPU Reset Button Wi-Fi LED Press Release 5 secs Firmware loading & flashing LED blinks fast ~ 3 mins Check bootup procedure Reboot Release Wi-Fi Reset Button When LED Turns Off Flash firmware LED Status Auto Restart 2015 MediaTek Inc. Page 13 of 15
6. Purchasing the LinkIt Smart 7688 development board 6.1. Where can I purchase the LinkIt Smart 7688 HDK? You can purchase the HDK from Seeed Studio's website (www.seeed.cc/7688). 2015 MediaTek Inc. Page 14 of 15
7. Going to market with LinkIt Smart 7688 based IoT device 7.1. How do I get my LinkIt devices to market? As part of the MediaTek Labs Partner Connect program we ll help you connect with prototype houses (such as Seeed Studio) as well as ODMs and device manufacturers, so that you can take the necessary steps towards commercializing your IoT devices. If you need help making those connections, please fill in a Company profile and create a submission to the MediaTek Solutions Catalog. 7.2. Where can I find more information or help on issues I encounter during development? If you encounter issues during development, the MediaTek LinkIt Smart 7688 Developer s Guide includes a Troubleshooting section that describes how to identify and correct issues. If the guide doesn t help solve your issue then there are SDK and HDK forums for LinkIt Smart 7688. Here you may be able to find (by searching for relevant words related to your issue) that others have encountered and solve the same issue. If you cannot find a solution then you can use the forum to pose a question to the Labs community. 2015 MediaTek Inc. Page 15 of 15