Zilog ZMOTION user manual

Application Note

ZMOTIONTM Detection Module
Application Walkthrough

AN030701-0810

Abstract

This application note describes in detail the application code associated with the ZMOTION Detection Module
and how it can be used for detection and cont rol applications. The ZMOTION Detection Module can be used
either in Hardware Mode or Serial Mode. In the Hardware Mode, you use the hardware circuit selecti on for
sensitivity adjustments, delay time settings, ambient light settings, and Sleep Mode. In the Serial Mode, you
can use the UART interface to fine-tune the ZMOTION Detection Module with advanced configuration
settings.

Note: The application code (AN0307-SC01) associated with this application note has been tested with

ZDS II—Z8 Encore! version 4.11.0.

ZMOTION Overview

Zilog’s ZMOTION Detection Module is a complete, compact, and easy to interface solution for motion
detection and direction. It is designed using an Enhanced Passive Infrared (ePIR) technology and Zilog’s
Z8FS04 Motion Detection MCU with a powerful embedded software engine that delivers high-performance
motion detection. Figure 1 on page 2 shows the location of the pins on the ZMOTION Detection Module.

Table 1 on page 2 describes the pin functions.

Copyright ©2010 by Zilog®, Inc. All rights reserved.

www.zilog.com

ZMOTIONTM Detection Module Application Walkthrough

Figure 1. ZMOTION Detection Module Pin Diagram

Operation Modes

There are two operation modes: Hardware Interface Mod e and Serial Interface Mode.
In the Hardware Interface Mode, you can make the following adjustments:

• Use the hardware interface pins for basic configuration.

• Adjust the motion sensitivity with the voltage on the SNS pin.

• Adjust the time delay (Output Active Time) with the voltage on the DLY pin

• Set the optional ambient light input.

• Use the Sleep Mode to reduce power consumption.

In the Serial Interface Mode, you can use the serial interface (Rxd and Txd) for advanced configuration:

• 9600 baud rate

• No parity

• 8 data bits

• 1 stop bit

• No flow control

The /MD, LG, and SLP pins remain functional.

Table 1. ZMOTION Detection Module Pin Description

Pin
No.

1
2
3

4

Signal

Name

GND Ground Ground
VDD Supply Voltage Supply Voltage
RXD/DLY DLY-Delay (analog

TXD/SNS SNS Sensitivity

Hardware Interface

Mode Serial Interface Mode Description

input)
(analog input)

RXD Receive Data (digital
input)

TXD Transmit Data (digital
input)

—
—
—

Mode select during Reset

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ZMOTIONTM Detection Module Application Walkthrough

Pin
No.

5

6
7
8

Signal

Name

/MD/RST Motion Detect (digital

LG Light Gate (analog
/SLP/DBG /SLP Sleep (digital
GND Ground Ground

Hardware Interface

Mode Serial Interface Mode Description

output)

input)
input)

Configurable: /RST Reset
(digital input)
/MD Motion Detect (digital
input)

Light Gate
(analog input)

/SLP Sleep
(digital input)

Default is /RST (Reset ) i n
Serial Interface Mode

If unused, connect to V
DBG is used for

programming and debug.

—

dd

.

Hardware Interface Mode Description

Figure 2 shows a typical example of how to connect the ZMOTION Detection Module using Hardware

Interface Mode. This mode of operation is selected when a voltage between 0 V and 1.8 V i s presented to the
SNS pin during power ON (or after a reset caused by Vbo). When the Hardware Interface Mode has been
established, this pin becomes the Sensitivity input and accepts a voltage between 0 V and 1.8 V as reference
for motion detection sensitivity level.

• 0 V = Highest Sensitivity

• 1.8 V = Lowest Sensitivity

In Figure 2, R2 and R4 form a simple potenti ometer resistor divider to ensure that the Hardware Mode is
entered upon reset and to control sensitivity levels.

Figure 2. Application Example of Hardware Interface Mode

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ZMOTIONTM Detection Module Application Walkthrough

After the application of power, the passive infrared sensor needs some time to stabilize. This typically takes
about 20 seconds but varies depending on environmental conditions. The software dynamically monitors the
pyroelectric sensor during power-up and begins detecting motion as soon as the sensor is stable.

The /MD (Motion Detect) pin is driven active (Low) when motion is detected. The voltage on the delay pin
(DLY) is used to determine the active duration o f the /M D si gnal. This can be easily set using a resistor divider
circuit shown in Figure 2 on page 3. With an 82-kA (R1) resistor tied to Vcc and values ranging from 0 A to
100 kA (R3) tied to ground, you can select d elay times from 2 seconds to 15 minutes. See Figure 2 on page 3
and Table 15 on page 20.

Table 2. Delay Times Using R1 = 82 K*

Delay Time R_DLY Voltage R_DLY Standard Resistor Value

2 sec 0 V 0 @
5 sec 0.2 V 5.1 k@
10 sec 0.4 V 11 k@
30 sec 0.6 V 18 k@
1 min 0.8 V 24 k@
2 min 1.0 V 33.2 k@
3 min 1.2 V 43 k@
5 min 1.4 V 56 k@
10 min 1.6 V 68 k@
15 min 1.8 V 91 k@

The Light Gate (LG) signal acts as a disable (gate) f or the /MD output signal. In a typical application, this
signal is a representation of the ambient light i n th e env i ronment. If there is light detected, the /MD signal does
not activate even in the presence of motion.

Serial Interface Mode C ommands

The Serial Interface Mode operates as a host - cl ient relationship where the ZMOTION Detectio n Module is the
client. Commands are sent from the host, and the module responds with the requested information or
confirmation. The only exception is when the module is configured for “/MD Unsolicited” operation. Under
this condition, it will send motion-detected information without first receiving a command from the host.

All the serial commands sent to the ZMOTION Detection Module are in ASCII character s f ormat, but the data
sent to and from the module can be ASCII or decimal.

There are three types of commands accepted by the module:

• Read commands

• Write commands

• Confirmation commands

Read Command Structure

Read commands are used to request information from the module. Read commands are sent from the h ost, and
the module responds with the requested data. See Figure 3 on page 5.

• All read commands are initiated by single lower-case letters.

• When received, the device will return the applicable value as described in

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ZMOTIONTM Detection Module Application Walkthrough

Table 16 on page 21.

Figure 3. Read Command Structure

Write Command Structure

Write commands are used to update configuration of the module. The command is sent from the host, and the
module responds with the current value as an acknowledgment. Then the host sends the new data, and the
module responds with an 'ACK'. See Figure 4.

• All write commands are initiated by single upper-case letters.

• When a write command is received, the device returns the current value and expects an appropriate single-

byte data value.

• When the data value is received, the device returns an 'ACK'. If no data is received after the inactivity

timeout of 2.5 seconds, the device returns a 'NACK'.

Figure 4. Write Command Structure

Confirmed Command Structure

Certain commands require a specific sequence of characters to be sent in order to help prevent accidental
initiation. These commands require a 4-character confirmation sequence. When a command r equiring
confirmation is received, the device returns an 'ACK' . See Figure 5.

• If the sequence is correct, the device returns an 'ACK' and executes the command.

• If the sequence is incorrect, or there is an inactivity delay of more than 2.5 seconds between any characters

of the sequence, the device immediately sends a 'NACK' and does not execute the command.

Figure 5. Confirmed Command Structure

Notes: 1. ACK = 0x06 (ASCII ACK character).

2. NACK = 0x15 (ASCII NACK character). The ZMOTION will respond with a 'NACK' on all

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ZMOTIONTM Detection Module Application Walkthrough

unrecognized commands or when a command requires data (that is, Write, Clear, and
Confirmation types) but does not receive the required data within the inactivity timeout period.

Software Overview

The application code in the ZMOTION Detection Module first executes an initialization procedur e, which is
discussed in the “Setting the Operational Mode” section on page 7. When the module is enabled, the ADC
interrupt runs in the background (see Figure 6). Every ADC conversion generates an interrupt and the
ZMOTION engine performs its functions during this time (see Figure 6). The user application code runs in the
foreground and monitors the status through the API and performs any other functions required for the
application, which is discussed in the “Main Application Loop” section on page 8.

Figure 6. ADC Interrrupt for ZMOTION Detection

One-Second Timer Tick

The ZMOTION engine requires a 1-second time base to perform various housekeeping operations (see Figure

7 on page 7). This is handled in the application by the timer interrupt. The Timer0 Interrupt is configured for

100 ms. The application code counts 10 of these interrupts and sets the Engine Timer Tick bit in ePIR_SC1.

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ZMOTIONTM Detection Module Application Walkthrough

1 Second

Timer Interrupt

Set bit 7 of ePIR_SC1

(Engine Timer Tick)

One

Second

Timer Tick

Return

Figure 7. One-Second Engine Timer Tick

Setting the Operation al Mode

The mode of operation (HW or Serial mode) can be selected using the TXD/SNS pin during the power ON or
when exiting the Sleep Mode. The following explains the program in the operational mode (see Figure 8 on
page 8):

1. The program starts by initializing all of the needed peripherals.

2. Check the Stop Mode Recovery SMR reset. If there is NO SMR reset, then the sensitivity level is

set to default and the ePIR status register is initialized.

3. The ePIR_ENABLE register is set to EPIR_ENABLE_PATTERN, so the engine can be enabled.

4. The EPIR_INIT macro is executed to initialize the ePIR engine.

5. Initialize Timer0 and set to 100-ms interrupt.

6. Check analog channel 0 (ANA0), which is connected to PIN4 or TXD/SNS if the analog level

exceeds the threshold or not. This is repeated 1 0 times to ensure a stable reading. If the TXD/SNS
pin is above the threshold, then the cCmdState is set to 1; else, it is set to 0. This is done t o
stabilize the ePIR engine.

7. Next, the mode of operation is determined with the value of the cCmdState. If the cCmdState is 1,

then the Mode of Operation is Serial Interface, and if the cCmdState is 0, then the Mode of
Operation is Hardware Interface.

8. Finally, the mode of operation is set, and cCmdState is set to IDLE state; it then proceeds to the

main application loop.

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ZMOTIONTM Detection Module Application Walkthrough

Figure 8. Flow Diagram of Operational Mode

Main Application Loop

Figure 9 on page 9 describes the main application loop of the ZMOTION Detection Module.

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ZMOTIONTM Detection Module Application Walkthrough

Figure 9. Flow Diagram of Main Application Loop of Application Code

The following describes the operation of the main application loop:

1. The program checks the Sleep pin if it is low. If the Sleep pin is low, then the program enters to

the Sleep Mode.

2. Next the program checks the content of the cModule Status1 (cModuleStatus1) flag. See Table 20

on page 23.

• If the Serial Mode Register (SER_MODE_ENABLED) is HIGH, several select cases are

available depending on the inputs of the select case. See

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