Functional Description

This manual is arranged in the following sections:

■ Operation

This general description of the operation and the functionalities is targeted at the user and application level.

■ Hardware Design

All information regarding hardware design aspects are covered here.

■ Instruction Set

Contains a detailed description of the data communication and the command set.

■ Optical Design Considerations

The chapter where the user finds some design guidelines for developing appropriate optics and illumination for the device.

1. Operation

1.1. Introduction

The epc610 chip is based on the 3D-TOF principle. Modulated light is sent out by a transmitter. This light is then reflected by the object to

be detected and the returning light is sampled by a photosensitive TOF CCD sensor. The receiver compares the phase difference between

the emitted and the received light and computes the time difference of the “time-of-flight” individually per pixel. This value multiplied by the

speed of light (ca. 300'000km/sec) and divided by 2 corresponds directly to the distance.

epc610

device

Backscattered light with time delay

dependent on the distance between

the object and the device

Object

Figure 11: The time-of-flight principle

1.2. General overview

The epc610 chip is designed to enable simple and cost effective system designs. Together with a microprocessor and few external compo -

nents, a fully functional TOF imager can be built (refer to Figure 12).

The epc610 system-on-chip contains:

■ A full data acquisition path with a power driver for the LED, the photo-receiver with 8x8 pixel TOF CCD array, the signal conditioning, the

A/D converter and the signal processing.

■ An on-chip controller managing the data acquisition and the data communication.

■ An SPI interface for the command and data communication.

■ A supply-voltage power management unit.

Microprocessor

nSS

epc610

MISO

LED

nSS

SCLK

MOSI

CCD

MISO

MOSI

SCLK

IR LED

< 180mA

SPI interface

OUT

3D TOF

picture

data

Figure 12: Basic application

The measurement functionality supports distance and ambient-light measurement with variable integration times, on-chip temperature

measurement for drift compensation.

The sensitivity of the system can be adjusted on the fly to the object reflectivity, the object distance and the ambient-light conditions by

means of integration time. The longer the integration time, the higher the sensitivity.

In cases where the illumination power of the built-in driver is not sufficient, the epc610 chip can also be used with an external LED driver.

This allows longer operational ranges or faster measurements, resulting in a faster response time and reduced ambient-light sensitivity.

© 2014 ESPROS Photonics Corporation

Characteristics subject to change without notice

9 / 34

Datasheet epc610 - V1.7

www.espros.ch