> For the complete documentation index, see [llms.txt](https://inacks.gitbook.io/inacks-is3720-i2c-dmx+rdm-receiver-ic/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://inacks.gitbook.io/inacks-is3720-i2c-dmx+rdm-receiver-ic/datasheet/memory-map/dmx_footprint.md).

# DMX\_FOOTPRINT

> This page is not the authoritative source for design information. The official [IS3720 datasheet](https://www.inacks.com/is3720) published on [www.inacks.com](http://www.inacks.com) is the authoritative reference: always consult it for the latest information.

The DMX\_FOOTPRINT register contains the quantity of DMX channels your device uses.

This register is very important in RDM, as it enables lighting operators to automatically patch your device. It tells the RDM controller how many DMX channels your device consumes. Using this information together with the DMX\_START\_ADDRESS, the lighting console can automatically patch your device at its location, reserve the required DMX slots, and assign the next RDM device to the next available DMX address — making a task that would normally take a long time fully automatic in just a second.

For example, let’s assume your device is an RGB light. In that case, you will need three channels: one for red, one for green, and one for blue. Therefore, the DMX footprint of your fixture will be 3.

But color channels are not the only ones that consume DMX addresses. Let’s suppose, in the previous example, that you use a fourth channel for the strobe frequency. In this case, the footprint of your device will be 4 — red, green, blue, and strobe frequency.

This register corresponds to the RDM parameter 0x0060 DEVICE\_INFO.

This is a 16-bit register composed by two 8-bit registers. Register address 519 is the high byte of DMX\_FOOTPRINT and register address 520 is the low byte.

Allowed values for this register block are 0 to 512.

This register block can be read and written via I2C, and it can be read via RDM.

This is a non-volatile register block. On each power-up, it loads its last stored value. Writing the same content to non-volatile memory that it previously held does not trigger a write cycle; therefore, it is safe to write to this register at every startup of your firmware.

* **Name:** DMX\_FOOTPRINT
* **Description:** DMX Footprint
* **Address Range:** 519 and 520
* **Memory Type:** Non-Volatile
* **Allowed Values:** 0 to 512
* **Accessible by:** I2C (Read/Write), RDM (Read Only)
* **RDM PID:** 0x0060 DEVICE\_INFO.CURRENT\_FOOTPRINT

| Addresses | Details   | Default Value |
| --------- | --------- | ------------- |
| 519       | High Byte | 0x00          |
| 520       | Low Byte  | 0x03          |