Freescale MMA7660FC ZSTAR3无线传感器设计方案

Freescale 公司的MMA7660FC ZSTAR3无线传感器采用MMA7660FC传感器和MC13213 MCU. MMA7660FC是±1.5 g 3轴带数字输出(I2C)的加速度计,是非常低功耗的小型容性MEMS,具有低通滤波器, 0g失调和增益误差补偿,能以用户可配置的取样速率(1-120次/秒)转换成6位数字值,模拟工作电压2.4V-3.6V,数字电压1.71V-3.6V.而MC13213采用40 MHz HCS08 低压低功耗的内核,有60 KB 闪存和4KB RAM存储器,多个16位计时器,工作电压2V-3.4V. ZSTAR3无线传感器主要应用在手机/PMP/PDA,便携式PC,游戏机和数码相机.本文介绍MMA7660FC和MC13213主要特性,方框图以及802.15.4 标准调制解调器方框图, ZSTAR3 传感器板方框图,电路图和材料清单(BOM).

The MMA7660FC is a ±1.5 g 3-Axis Accelerometer with Digital Output (I2C). It is a very low power, low profile capacitive MEMS sensor featuring a low pass filter, compensation for 0g offset and gain errors, and conversion to 6-bit digital values at a user configurable samples per second. The device can be used for sensor data changes, product orientation, and gesture detection through an interrupt pin (INT). The device is housed in a small 3mm x 3mm x 0.9mm DFN package.

MMA7660FC主要特性:

• Digital Output (I2C)

• 3mm x 3mm x 0.9mm DFN Package

• Low Power Current Consumption: Off Mode: 0.4 μA, Standby Mode: 2 μA, Active Mode: 47 μA at 1 ODR

• Configurable Samples per Second from 1 to 120 samples a second.

• Low Voltage Operation:

– Analog Voltage: 2.4 V - 3.6 V

– Digital Voltage: 1.71 V - 3.6 V

• Auto-Wake/Sleep Feature for Low Power Consumption

• Tilt Orientation Detection for Portrait/Landscape Capability

• Gesture Detection Including Shake Detection and Tap Detection

• Robust Design, High Shocks Survivability (10,000 g)

• RoHS Compliant

• Halogen Free

• Environmentally Preferred Product

• Low Cost

MMA7660FC典型应用:

• Mobile Phone/ PMP/PDA: Orientation Detection (Portrait/Landscape), Image Stability, Text Scroll, Motion Dialing, Tap to Mute

• Laptop PC: Anti-Theft

• Gaming: Motion Detection, Auto-Wake/Sleep For Low Power Consumption

• Digital Still Camera: Image Stability

图1.MMA7660FC简化功能方框图

The MC13213 provides 60 K Flash memory and 4 K of RAM. By using the IEEE® 802.15.4 Compliant MAC, or BeeStack  ZigBee Protocol Stack, the MC13213 is an ideal solution for sensing and control applications that require mesh networking.

MC13213主要特性:

• 40 MHz HCS08 low-voltage, low-power core

• 60 KB Flash and 4KB RAM memory

• Seven addressing modes for the CPU

• Multiple 16-bit timers

• 2 V to 3.4 V operating voltage with on chip voltage regulator

• -40 to +85 ℃operating temperature

• Low external component count

• Requires a single 16 MHz crystal

• Programmable frequency clock output for MCU

• Auto-trim feature for crystal accuracy

• Eliminates the need for external variable capacitors

• Allows for automated production frequency calibration

• 9 x 9 x 1 mm 71-pin LGA package

• RoHS compliant

• Up to 38 GPIO’s

• 8-bit port KeyBoard Interrupt (KBI)

• 8-channel 10-bit Analog-to-Digital Converter (ADC)

• Two independent Serial Communication Interfaces (SCI) supporting up to 115.2 kBaud

• Inter-integrated circuit (I2C) with 100 kbps maximum bus loading

• Internal Clock Generator (ICG) at 100 kHz or 16 MHz (including internal reference generator)

• Low-voltage detection

• In-circuit debug and Flash programming available via on-chip background debug module (BDM)

• Programmable Low Voltage Interrupt (LVI)

• Common On-chip Processor (COP) watchdog timer

• Operates in the 2.4GHz band

• 250 kbps O-PQSK modulation

• 16 selectable channels

• 0 dBm nominal output power

• Programmable from -27 dBm to +3 dBm

• Receive sensitivity of -92 dBm (typical) at 1% PER

• Integrated transmit/receive switch

• Supports single-ended or full differential operation

• Supports external Low-Noise Amplifier (LNA) and/or Power Amplifier (PA)

• Three lower power modes for increased power life

• Supports streaming and data processing modes

Software Features:

• Simple MAC

— Small memory footprint (< 4 KB)

— Supports point-to-point and star network configurations

— ANSI C source code

• IEEE 802.15.4 compliant MAC

— Supports star, mesh and cluster tree topologies

— Supports beaconed and non-beaconed networks

— Supports Guaranteed Time Slots (GTS) for predicable latency

— 128-bit Asymmetric Encryption Standard (AES)

— Object Code

• BeeStack ZigBee Protocol Stack

— ZigBee 2006 Compliant Platform

Object Code

图2.MC1321x 系统级方框图

图3.802.15.4 标准调制解调器方框图

ZSTAR3系统

The ZSTAR3 system accommodates multiple digital and analog accelerometer boards,connected through an RF ZigBee® 2.4 GHz communication to a single USB node connected to a PC. The accelerometer boards measure acceleration in three axes using a pin compatibledigital or, optionally, an analog sensor. The sensor sensitivity is defined by the selected accelerometer. The USB node is part of the ZSTAR design, equipped with dedicated software supporting multiple nodes.

Freescale is now offering the next-generation ZSTAR3 with the MMA7660FC accelerometer that offers extended functionality. The new PC software showcases the built-in intelligence of the MMA7660FC for consumer applications with orientation, shake, tap detection, auto-wake and auto-sleep. The ZSTAR3 is a small portable board design that utilizes the following products:

• MMA7660FC or MMA7455L digital triple-axis accelerometers

• MC1321x 2.4 GHz low-power transceivers and an S08 MCU in one package

• MC68HC908JW32 USB 2.0 full-speed 8-bit MCU

ZSTAR3系统典型应用:

The ZSTAR3 design provides small portable boards with the capacity to demonstrate and evaluate various accelerometer applications that accommodate a cost-effective,low-power wireless connection. Applications include:

• Mobile phones

• Hand-held gaming devices

• Portable media players

• MP3 players

• PDAs

• Personal computer peripherals

• GPS navigation devices

• Remote controls

Features of ZSTAR3

• Sensing acceleration in 3 axes

• Handles digital and analog sensors

• Wireless communication with sensors through the 2.4 GHz band

• RF protocol supports 16 sensors per one USB stick (receiver)

• Star topology of the RF network

• Data rate of a sensor is 30, 60 or 120 Hz

• Typical wireless range is 20 m, two walls or one floor

• Auto calibration function of the sensor

• USB communication on the receiver part

— Virtual serial port - interface for the GUI and serial port terminal

— HID class - mouse for windows

— HID class – keyboard (game controller)

• 8-bit/16-bit working modes

• 3 push buttons on the sensor board

• Current consumption:

— in normal run mode: 1.8 - 3.9 mA, depending on the actual data rate

— in sleep mode: less than 900 nA

• Power consumption depends on the current output values of the sensor. At a standstill, the board transmits only every 10th packet

• Sensor Board is powered by a coin-sized CR2032 3 V battery

• Small size board fits a circular plastic box.



图4.ZSTAR3 传感器板

图5.ZSTAR3 传感器板方框图

图6.ZSTAR3 传感器板电路图- Revision 00288_02

图7.ZSTAR3 传感器板电路图- Revision 00288_04

传感器板材料清单(BOM)- MMA7660FC 传感器