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Getting Started — Step by Step

This guide applies to both the standalone DimmerLink module and the built-in DimmerLink controller inside a Dimmer module.

Step 1: Connect to a Serial Terminal

By default, DimmerLink operates in UART mode. To verify it's working, connect DimmerLink to any USB-UART adapter such as CH340, CP2102, or CP2104.

Open a serial terminal that supports: - HEX input/output mode - Port configuration (baud rate, data bits, etc.)

Recommended terminals: - VS Code — Serial Monitor extension - Advanced Serial Port Monitor - RealTerm, CoolTerm, SSCOM

This guide uses VS Code Serial Monitor as an example.

Port Settings

Parameter Value
Baud Rate 115200
Data Bits 8
Parity None (N)
Stop Bits 1
Format 8N1

Step 2: Power Up and See the Welcome Message

  1. Open the serial port in your terminal first
  2. Then connect DimmerLink to the USB-UART adapter (or power it on)

This order ensures you catch the startup message:

You should see:

plaintext
=== DimmerLink vX.XXX ===
Mode: UART
Calibrating...

Step 3: Complete the Calibration

DimmerLink starts by calibrating the AC mains frequency. This is the highest priority task at startup — the controller waits for Zero-Cross events from the AC mains before accepting any commands.

To complete calibration:

  1. Make sure the dimmer module is connected to AC mains. A load (lamp) is not required at this stage — only the mains connection matters.
  2. Restart DimmerLink — disconnect VCC and reconnect it (or briefly short VCC to GND to trigger a reset).

After successful calibration you will see:

The message shows: - Detected mains frequency (50 Hz or 60 Hz) - Phase period in microseconds - Active dimming curve - "UART mode ready"

Step 4: Switch Console to HEX Mode

DimmerLink communicates using a binary (HEX) protocol. Before sending commands, switch your terminal's input mode to HEX.

Now try setting brightness to 50%. Send this HEX command:

plaintext
02 53 00 32
Byte Meaning
02 Start byte (STX)
53 SET command ('S')
00 Dimmer index 0
32 50% brightness (0x32 = 50 decimal)

Step 5: Read the Response

DimmerLink responds in HEX format. Switch your terminal's output display to HEX mode to see the responses clearly.

A response of 00 means the command was executed successfully.

Response Meaning
00 OK — command executed
F9 Syntax error — unknown command
FC Flash write error
FD Invalid dimmer index
FE Invalid parameter value

Step 6: Switch to I2C Mode (Optional)

If you need I2C instead of UART, send the switch command:

plaintext
02 5B

Response: 00 (OK — this is the last UART response).

After this, DimmerLink: - Switches to I2C mode immediately - Stops responding to UART commands - Stops sending messages to the terminal - Remembers the mode — after reboot it will start in I2C mode

To switch back to UART from I2C, send command 0x03 to I2C register 0x01 (COMMAND register). See I2C Communication for details.

Quick Command Reference

Action HEX Command Expected Response
Set 0% (off) 02 53 00 00 00
Set 25% 02 53 00 19 00
Set 50% 02 53 00 32 00
Set 75% 02 53 00 4B 00
Set 100% 02 53 00 64 00
Get brightness 02 47 00 00 + level byte
Get mains frequency 02 52 00 32 (50 Hz) or 00 3C (60 Hz)
Set RMS curve 02 43 00 01 00
Switch to I2C 02 5B 00

Troubleshooting

Symptom Cause Solution
No startup message Port opened after power-up Open port first, then power on DimmerLink
Stuck on "Calibrating..." Dimmer not connected to AC mains Connect mains power, then restart DimmerLink
Commands not executing Still in calibration Wait for "UART mode ready" before sending commands
No response to commands Terminal sending ASCII, not HEX Switch console input to HEX mode
No response to commands DimmerLink is in I2C mode Reconnect via I2C and send SWITCH_UART command
Wrong frequency detected Noisy restart Power-cycle DimmerLink cleanly

Support

If you need technical assistance: - Visit your account at rbdimmer.com - Email: [email protected]

What's Next?

Step 1: Connect to a Serial Terminal Step 2: Power Up and See the Welcome Message Step 3: Complete the Calibration Step 4: Switch Console to HEX Mode Step 5: Read the Response Step 6: Switch to I2C Mode (Optional) Quick Command Reference Troubleshooting Support What's Next?