MCU Access

Tuya Gateway Development Overview

Introduction

This article is mainly an overview of the MCU development process of Tuya Gateway general solution.

Development Process

The development process mainly includes: product creation-hardware debugging-software development-functional debugging.

Create Product

Log in to the IoT Workbench and create a product. Select the product category according to the actual needs, and select Wi-Fi for the networking method. After the product is created, you can select the functions, panels, modules, and firmware according to the actual needs of the product and then download it to the MCU development kit.

The specific steps to create a product can refer to: Product Creation-IoT Platform Operation

Hardware debugging

Hardware selection

When creating a product selection module, the platform will recommend some common module models. At present, the gateway MCU access solution can only be provided by Wi-Fi gateway module-WRG1.

After selecting the module and firmware, you can purchase module samples online.

The hardware engineer can enter the drawing board stage, and the related materials for hardware development can be viewed in the document center:

Data manual link: Wi-Fi Gateway Module-WRG1 Datasheet

Module minimum schematic: Wi-Fi Gateway Module-WRG1 minimal system schematic diagram PCB data: Common module package library

Distribution Network Verification

After getting the module, users do n’t need to worry about writing code first. It is recommended to use the module debugging assistant (MCU simulation mode) provided by Tuya to connect with the WRG1 module first. When verifying the module, users can be familiar with The protocol interaction process will greatly improve the efficiency of development and debugging later.

Tuya module debugging assistant-MCU simulation mode. The assistant will simulate the MCU to automatically reply the module's correct protocol data. After the module is networked with a mobile phone, the DP data can be reported and issued. The following briefly introduces the main steps of the assistant and module distribution network operation. Before using it, you need to know the instructions of Tuya Module Debugging Assistant in advance. Users who use the assistant for the first time can read in advance: Module Debugging Assistant Instruction

step1. According to the minimum system schematic diagram, set up the module peripheral circuit, and simple test can directly fly the wire.

step2. Set device capabilities,open the Tuya module debugging assistant in the development kit and import the debugging file. Protocol selection Wi-Fi gateway protocol, MCU simulation mode.

step3. Connect the serial port of the module to the computer through the USB to TTL tool. The assistant selects the corresponding serial port and baud rate. Open the serial port and click Start. You will see that the module and the host computer automatically perform the initialization process protocol interaction.

Note: If no data is sent after power on, please check if the peripheral circuit of the module is correct.

step4. Click Reset Module, the module enters the network distribution mode. The module supports two modes of network configuration: EZ and AP mode (the difference between EZ mode and AP mode). The reset button will switch the network configuration mode. According to the status prompt, the App performs the corresponding network configuration operation. For the network configuration operation, you can read the instruction of the App. Attach a demo video of the network distribution in two modes: Wi-Fi module network distribution demonstration video.

Software Development

In the process of hardware debugging, the user saw that the module and the MCU have a series of serial protocol protocol interaction data. For the understanding of these data, please refer to the protocol document in the development kit.

The agreement is mainly divided into two parts: the basic agreement and the functional agreement. The basic protocol has nothing to do with the product. It is a common protocol of the module, including module initialization instructions and some extended function instructions. The function protocol part is mainly based on the command word of the report of the basic protocol, and has explained the DP data content format in detail. The complete content of the basic protocol, the document center is kept updated in real time, you can click the link to view: Tuya Cloud Gateway Access Protocol

There are two ways for MCU to interface with Tuya module: transplant the MCU SDK or connect the protocol by yourself.

• Self-docking agreement

  When MCU resources are limited or the MCU SDK is not suitable for porting, customers can choose to connect the serial port protocol by themselves. The detailed explanation of serial port protocol can refer to: Tuya Cloud Gateway Access Protocol Analysis

• Porting MCU SDK

  If the MCU resources are sufficient, it is generally recommended that users directly port the MCU SDK for efficient and convenient development. The MCU SDK in the development kit is a C-based protocol application code provided by Tuya, which can be directly added to the MCU project. The MCU SDK requires MCU hardware resources: 4K bytes of Flash; RAM is related to the length of the DP point data, about 100 bytes (if OTA function is required, it must be greater than 260 bytes); the number of function nesting levels is 9 levels. If users with insufficient resources can connect the protocol by themselves, the functions in the SDK package can still be used as a reference.

MCU SDK porting tutorial, please refer to: Tuya Wi-Fi Gateway MCU_SDK Instructions

Functional debugging

After porting the MCU SDK code development, you can use the Tuya module debugging assistant-module simulation mode to verify the correctness of the MCU code. The usage method is similar to the MCU simulation mode. In the simulation module mode, the assistant will automatically send the initialization data stream to verify that the MCU response is correct and give corresponding prompts for the incorrect data. After the initial interaction is passed, you can manually click to test other extended functions.

Note: Tuya module debugging assistant module simulation mode, without networking function, only used to verify the correctness of MCU serial protocol transmission and reception. After the test is completed, the MCU can be connected to the actual module and network.

Debugging common tool links:

Background log query entry: IoT Workbench-Operation Center. You can query related device background log data based on the device ID.

Tuya Online Support Portal: Tuya provides online support services. If the problem documents cannot be answered, you can Ask questions directly online, and the professional and technical team will answer your questions.

Tuya Gateway MCU Access Communication Protocol

Version Record：

Serial communication convention

Baud rate：115200

Data bit：8

Parity: None

Stop bit：1

Data flow control: none

MCU：User will control the chip through control board, connected with Tuya module through serial port

Frame format description

Basic agreement details

Query product information

Description：

1. product ID：Corresponding to the PID on Tuya IoT Platform, generated by Tuya IoT developer platform, used to record product related information in the cloud

2. The product information is comprised by product ID and MCU version

3. MCU version number format definition: in dotted decimal format，”x.x.x”（0<=x<=99），x is decimal.

Module send：

For example：0x55aa 00 01 0000 00

MCU return：

For example：{“v”:”1.0.0”,”m”:1,”cap”:0, “tp”:4,“p”:”mhnmpqzf7ntzmmdb”}

v means MCU version is 1.0.0

m represents pairing methods: 0 default pairing mode、1 Low power consumption mode、2 special pairing mode

cap represent device ability: bit0(local group)，bit1(local scene) ，bit2(gateway have function dp), bit3(is sigmesh), bit4(support MCU upgrade), bit5(group control command with sub_id) , bit6 (Bluetooth serial port paring mode，otherwise just AP mode is available)(the bit unused is 0）

Case 1: device support the local group control， cap is 1:

Case 2：device support local group control and local scene，cap is 3;

Case 3：device does not support local group control and local scene, but the gateway has function dp, cap is 4

Case 4：device is sigmesh device, with local group，it has to issue sub_id when control the group(issue 0x22 command), cap is 41（0x29）

tp represents the sub-devices type integrated： 1:Zigbee 2:Bluetooth 3:Smart IR 4:Others if tp is not transmitted, it will be others defaultly； Pls note：The type of sub-devices: zigbee/Bluetooth/Smart IR are applied for Tuya self-developed products, if it the products developed by the customers, the sub-devices category will be others. p represent gateway product pid，pid is mhnmpqzf7ntzmmdb

Querying MCU, set the working mode of the module

Description：

1. The working mode of the module is mainly for how to indicate the working status of the Wi-Fi module and how to reset the Wi-Fi module. There are two main cases：

2. MCU cooperates with the module, that is, the module notifies the MCU through the serial port, the current working status is supported by the MCU, the Wi-Fi will be reset through the serial port when the MCU detect the reset request.

3. Module self-processing: The working status of the WIFI module drives the LED status display through the WIFI GPIO pin; WIFI reset is processed by detecting the GPIO input requirements

The method of resetting the Wi-Fi module through module self-processing：WIFI will be triggered when detecting that the low level of GPIO entrance last for more than 5s. Reset: The GPIO pins used by the indicators and buttons are configured by the following commands.

Module send：

For example：0x55aa 00 02 0000 01

MCU return：

For example：0x55aa 00 02 0000 04（MCU work with the module）

0x55aa 00 02 0004 0103 0102 0C（module self-processing，indicator 0x0103：PB_3，reset button 0x0102：PB_2）

Report the device connection status

Description：

1. Device connection status：1 smart configuration status 2 AP configuration status 3 WIFI is configured but not connected to the router 4 WIFI is configured and connected to the router 5 Device is connected to the router and the cloud. The LED indicator under 'module self-processing' working mode is：1 Flashing at intervals of 250ms；2 Flashing at intervals of 1500ms；3 Long dark status；4 or 5 Long light status

2. When the module detects that the MCU restarts or the MCU is disconnected and then goes online, it will sends the WIFI status to the MCU actively.

3. When the WIFI status of the module changes, it will actively send the WIFI status to the MCU

4. If the module working mode is set to 'module self-processing', the MCU does not need to implement this protocol

Module send：

For example：0x55aa 00 03 0001 00 03

MCU return：

For example：0x55aa 00 03 0000 02

Reset WIFI

Description：

2. If the module working mode is set to 'module self-processing', the MCU does not need to implement this protocol

MCU send：

For example：0x55aa 00 04 0000 03

Module return：

For example：0x55aa 00 04 0000 03

Reset WIFI-select the configuration mode

Description：

1. Compared with 'Reset WIFI' in section 3.5, this section provides the MCU to selectively choose the configuration method after resetting the WIFI depend on different conditions.

2. MCU solution users can selectively implement this protocol depend on their requirements.

3. If the module working mode is set to 'module self-processing', the MCU does not need to implement this protocol

MCU send：

For example：0x55aa 00 05 0001 00 05，get into smart configuration mode

Module return：

Foe example：0x55aa 00 05 0000 04

Allow sub-device to access the network

Description：

1. The App sends a network access permission to the Gateway, and allows the sub-device to access the network within a certain period of time.

Module send：

MCU return：

Disable the permission of sub-device accessing the network

Description：

The App sends a command to close the network to the Gateway

Module send：

MCU return：

Add sub-device

Description：

1. MCU send the sub-device network access to Wi-Fi

2. pk_type is alternate field, can be ignored, the default value is 1

MCU send：

Module return：

Delete the sub-device

Description：

The App sends a command to close the network to the Gateway.

Module send：

MCU return：

Heartbeat detection

Description：

WIFI module schedule（1-3 mins）detect the online/offline status of sub-device. When adding sub-devices in batches,heartbeat detection will stop.

Module send：

MCU return：

| Field | Length（byte） | Description |

| -------- | --------------------------------- | ------------------------------------------------------------ | | Header | 2 | 0x55aa | | Version | 1 | 0x00 | | Command word | 1 | 0x0A | | Data length | 2 | N | | Data | { “sub_id”:“xxxx”, “hb_time”:xx } | sub_id：sub-device ID Heartbeat intervalhb_time（Unit: second）for example：60 means 60 seconds，0 does not support heartbeat，always online。If the heartbeat interval is less than 180s, it will be processed for 180s (except 0) | | Checksum | 1 | The result obtained by summing bytes from the beginning of the frame to the remainder of 256 |

Description：

The online device needs to responde to the heartbeat. If it does not reply for two consecutive heartbeat cycles, the device is considered offline.

Status query

Description：

Used to synchronize the status of sub-devices.

Module send：

MCU return：（3.13 status report）

Command issue

Description：

Control command issue.

datapoint: command status unit:

1. datapoint: the command / status data unit is as follows:

1. datapoint command/ except for the 'raw' type, other types of state data units belong to the 'obj' type datapoint

2. 'command issue' contains several datapoint 'command data unit'

3. 'command issue' is asynchronous processing protocol，corresponding to MCU datapoint 'status report'

Module send：

Status report

Description：

The sub-device actively pushes the instruction after the command is issued and replied or the status changes.

MCU send：

| Field | Length（byte） | Description |

| -------- | ---------------------------------------- | ------------------------------------------------------------ | | Header | 2 | 0x55aa | | Version | 1 | 0x00 | | Command word | 1 | 0x0D | | Data length | 2 | N | | Data | id_len(1byte) + sub_id(nbyte)+ datapoint | id_len: sub-device id length sub_id: sub-device id. when the sub_id is '0000',this command is to the gateway itself's dp (main device) . datapoint: Control command data point collection | | Checksum | 1 | The result obtained by summing bytes from the beginning of the frame to the remainder of 256 |

Group sub-device join in

Description：Local group sub-devices are added, support local group-created devices. Module send：

MCU return：

Group sub-device deletion

Description：The local group sub-device is deleted.

Module send：

MCU return：

Get system time (Green Time)

MCU send：

For example：0x55aa 00 10 0000 0F

Module return：

For example：0x55aa 00 10 0007 01 10 04 13 05 06 07 50（April 19, 2016 5: 6: 7 GMT）

Obtain system time

MCU send：

Module return：

For example：

(1)If the device is activated in China, the local time is Beijing time (East 8 District)

0x55aa 00 11 0008 01 10 04 13 05 06 07 02 54（Beijing time April 19, 2016 5: 6: 7）

(2)If the device is activated abroad, the local time is the time zone of the device

Add devices in bulk

Description：Add multiple sub-devices of the same pid in batch. Note：The maximum number of sub-devices added in a batch is 32. MCU send：

Module return：