Introduction

My smart home infrastructure contains several Xiaomi humidity/temperature and door sensors. I’ve used these sensors with the corresponding Xiaomi gateway. The gateway was connected with my BananaPi M2U and Pimatic. But my home is long and tall. One gateway does not cover all rooms, and therefore far sensors disappear periodically.

I’ve googled and found I can use Xiaomi sockets (Zigbee edition) like Zigbee routers. This socket is less expensive than a new gateway, and it has a smaller size. I’ve purchased two sockets and used them for about a month. This socket has a big problem (from my standpoint). It can go into the deep sleep mode and cannot forward data packets from sensors.

I’ve decided to use a CC2530 based development board and build my router. Aliexpress.com offers some variants. I’ve purchased two samples:

1. This board will be used in my Zigbee router.

2. This board will be used in Banana Pi as a coordinator instead of the CC2531 USB stick. This board has an external antenna, and I hope it will work better.

Firmware for Zigbee Coordinator

Z-Stack Home Automation SDK 1.2.2a comes with a precompiled firmware for CC2530 ZNP (Projects\zstack\ZNP\CC253x\bin\CC2530ZNP-SB.hex), but all my attempts to launch it on my samples failed. The gateway software xiaomi-zb2mqtt cannot detect and work with boards through a UART port.

RS232 pins:

P0_2 <=> RS232 RX
P0_3 <=> RS232 TX
P0_4 <=> RS232 CTS
P0_5 <=> RS232 RTS

The precompiled firmware uses hardware flow control wires. If you do not want to use it, you must connect P2_0 (CFG1) to GND.

So I’ve installed the trial version of IAR Embedded Workbench for 8051 (CC2530 is based on this processor architecture) and compiled the “SampleLight” demo application as a coordinator. Yes, of course, it may take some time. Below are my defined symbols:

 SECURE=1
 TC_LINKKEY_JOIN
 NV_INIT
 NV_RESTORE
 xHOLD_AUTO_START
 ZTOOL_P1
 MT_TASK
 MT_APP_FUNC
 MT_SYS_FUNC
 MT_ZDO_FUNC
 HAL_LCD=FALSE
 xLCD_SUPPORTED=DEBUG
 MULTICAST_ENABLED=FALSE
 xZCL_READ
 xZCL_WRITE
 xZCL_REPORT
 xZCL_EZMODE
 xZCL_BASIC
 xZCL_IDENTIFY
 xZCL_ON_OFF
 xZCL_SCENES
 xZCL_GROUPS
 xZCL_LEVEL_CTRL
 xZCL_DIAGNOSTIC
 FEATURE_SYSTEM_STATS
 MT_UART_DEFAULT_BAUDRATE=HAL_UART_BR_115200
 MT_UART_DEFAULT_OVERFLOW=FALSE
 HAL_LED=FALSE
 HAL_SPI=FALSE
 MT_UTIL_FUNC
 MT_AF_FUNC
 MT_SAPI_FUNC
 MT_SAPI_CB_FUNC
 MT_ZDO_CB_FUNC
 MT_ZDO_FUNC
 MT_SYS_FUNC
 OSAL_SAPI=FALSE
 SAPI_CB_FUNC=FALSE
 xHAL_UART_DMA_RX_MAX=128
 MT_TASK_CUSTOM
 MT_ZDO_MGMT

How to use

Download and flash the firmware.

Baud rate: 115200
Hardware flow control: Disabled
P2_o pin state: ignored
P0_2 <=> UART (RS232) RX
P0_3 <=> UART (RS232) TX
UART port uses the DMA mode.
You may also connect to this port using ZTool.

Firmware for Zigbee Router

I’ve used the source code of the “SampleLight” demo application for my router’s firmware. I did some modifications and improvements:

• The pre-configured manufacturer code for Xiaomi devices.
• The pre-configured security key.
• LED blinking for some states:
  • Short fast blinks (one per second) – the router is connecting to a network.
  • Short long blinks (one per 4 seconds) – normal operations.
  • Three short blinks – the router cannot send a report to a coordinator.
• The router sends the “genOnOff” report to a coordinator every minute (you may configure an interval using the corresponding ZCL command). It works like a keep-alive message.
• The debug version of the firmware additionally sends the “genBinaryValue” report for every neighbor in a network:

description – network and MAC address.
inactiveText – device role in a network.
presentValue – RSSI value of the last received packet (rxLqi).
relinquishDefault (optional) – path depth.
minimumOffTime (optional) – number of associated devices.

Defined symbols from the project:

 SECURE=1
 TC_LINKKEY_JOIN
 NV_INIT
 NV_RESTORE
 xHOLD_AUTO_START
 ZTOOL_P1
 MT_TASK
 MT_APP_FUNC
 MT_SYS_FUNC
 xMT_ZDO_FUNC
 LCD_SUPPORTED=DEBUG
 xHAL_LCD=FALSE
 HAL_SPI=FALSE
 MULTICAST_ENABLED=FALSE
 ZCL_READ
 xZCL_WRITE
 ZCL_REPORT
 xZCL_EZMODE
 ZCL_BASIC
 xZCL_IDENTIFY
 ZCL_ON_OFF
 xZCL_SCENES
 xZCL_GROUPS
 xZCL_LEVEL_CTRL
 xZCL_DIAGNOSTIC
 ZCL_DISCOVER
 FEATURE_SYSTEM_STATS
 MT_UART_DEFAULT_BAUDRATE=HAL_UART_BR_115200
 MT_UART_DEFAULT_OVERFLOW=FALSE
 HAL_LED=TRUE
 MT_UTIL_FUNC
 HAL_KEY=TRUE
 ZSTACK_MANUFACTURER_CODE=4447
 BLINK_LEDS
 DIAG_INFO_REPORT

How to use

1. Download and flash the firmware.

2. Power off/on (restart) the router.

3. Permit joining to a network on your coordinator.

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UPDATE 2020-09-28

Added the “Aging” mode. The router forgets child devices that didn’t send any data for four hours. It helps when an end-device selects a new path to a coordinator.

UPDATE 2018-09-26

1. Allows a router to use all possible channels (the old firmware was used the channel #11). But now, the router will take more time to connect to a coordinator.
2. A router may report link quality for all connected neighbors.

UPDATE 2019-02-04

1. The previous version allowed joining for deleted devices.
2. СС2530 can be re-paired if you power on/power off it three times (power on, wait 2 seconds, power off, repeat this cycle three times).