EVM-900-DT View Datasheet(PDF) - Unspecified

Part Name

Description

Manufacturer

EVM-900-DT

HumDT™ Series RF Transceiver Module

Unspecified 

Initialization Complete Message - Response Code = 7A

Once the module has completed its power-up initialization routines and

joined the network, it outputs the message shown in Figure 56.

Initialization Complete Message

Start Response Param 1

End

3C

7A

DType

3E

Figure 56: Initialization Complete Message

The DType parameter is the device type that the module has assumed

during initialization. These codes are shown in Figure 57.

Device Type Codes

Device Type

Access Point (AP)

Range Extender (RE)

End Device (ED)

Device Type Code (hex)

31

32

33

Figure 57: Baud Rate Codes

The microcontroller can confirm that this is the correct device type for the

application and make changes as necessary.

– 52 –

Typical Applications

Figure 58 shows a typical circuit using the HumDTTM Series transceiver.

RXD

µ TXD

GPIO

GPIO

GND

VCC

GND

GND

GND

Sensor

GND

30 MODE_IND

31 ACTIVE

32 GPIO_0

1 GPIO_1

2 GPIO_2

3 GPIO_3

4 GPIO_4

GND 20 GND

ANT 19

GND 18 GND

GND 17 GND

GND 16 GND

GND 15 GND

GND 14 GND

GND

Figure 58: HumDTTM Series Transceiver Basic Application Circuit

An external microcontroller provides data and configuration commands. It

also controls the POWER_DOWN line to place the module into a low power

state.

A sensor is connected to GPIO_1. This sensor outputs an analog voltage

that is proportional to the parameter being measured. GPIO_1 is set as an

analog input and the microcontroller can query the voltage state of the line.

The VCCD lines are not connected in this example. These lines are unused

inputs with 20k resistors to VCC. They should be connected directly to VCC

if noise on the board or in the environment could cause voltage drops on

the lines that fall below the VIH specification. This is not likely to be an issue

with most battery-powered devices, but could be a problem with designs

containing switching power supplies or used near motors or other sources

of high-level EMI. This should be tested with all designs.

– 53 –

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