Digi XBee modules have pins that can be configured to perform as a digital output or input (DIO), as an analog input (ADC) or as an analog output (PWM).
This mbed library offer functionality to manage those pins on Remote Devices. That is achieved by sending RF messages to the remote radio from the local radio attached to the mbed processor.

Available methods¶

The same functionality is offered for ZigBee and 802.15.4 modules, although the pin (IoLine) names and functionality available on those pins are different:

Line parameter¶

Mode parameter¶

IoMode enum used in set_pin_config() and get_pin_config()methods can take following values: Disabled, SpecialFunc, Adc, Pwm, DigitalInput, DigitalOutLow and DigitalOutHigh.

DIO value parameter¶

DioVal enum used in set_dio() and get_dio() methods can take following values: DIO_LOW and DIO_HIGH.

ADC value parameter¶

get_adc() method takes an uint16_t as value argument. The value stored in val represent the analog value of the pin ranging from 0 to 0x3FF.

PWM value parameter¶

set_pwm() and get_remote_pwm() methods take a float as duty_cycle argument ranging from 0.0 to 100.0.

Examples¶

To simplify the examples and make them independent of the hardware and the XBee variant, the following pins are used for this examples set:

The first step for every example, is to create the local and the remote devices. They can be either ZigBee or 802.15.4 devices:

#include "XBeeLib.h"
  
using namespace XBeeLib;
 
void main()
{
     [...]
      
     XBeeZB xbee = XBeeZB(RADIO_TX, RADIO_RX, RADIO_RESET);
     xbee.init();
 
     RemoteXBeeZB remoteDevice = RemoteXBeeZB(0x0013A200AABBCCDD);
  
     [...]
}

Setting the value of a Digital Output¶

The example toggles DIO4 pin every 5 seconds. If a led is connected to this pin as shown in the schematic, it should blink every 5 seconds.

[...]
 
while(true) {
    static bool led_on = false;
     
    if (led_on) {
        radioStatus = xbee.set_dio(remoteDevice, XBeeZB::DIO4, DIO_LOW);
    } else {
        radioStatus = xbee.set_dio(remoteDevice, XBeeZB::DIO4, DIO_HIGH);
    }
     
    MBED_ASSERT(radioStatus == Success);
     
    led_on = !led_on;
     
    wait(5);
}
 
[...]

Getting the value of a Digital Input¶

The example samples the digital value of DIO3_AD3 pin every 5 seconds. If this pin is connected to a push-button as shown in the schematic, the application should report "DIO3 value = 0" if the button is pressed and "DIO3 value = 1" otherwise.

[...]
 
radioStatus = xbee.set_pin_config(remoteDevice, XBeeZB::DIO3_AD3, DigitalInput);
MBED_ASSERT(radioStatus == Success);   
 
while(true) {
    DioVal dio3_val;
     
    radioStatus = xbee.get_dio(remoteDevice, XBeeZB::DIO3_AD3, &dio3_val);
     
    MBED_ASSERT(radioStatus == Success);
     
    log_serial->printf("DIO3 value = %d\r\n", dio3_val);
     
    wait(5);
}
 
[...]

Getting the value of an ADC¶

The example samples the analog value of DIO2_AD2 pin every 5 seconds. If this pin is connected to a variable resistor as shown in the schematic, the application should report it's value ranging from 0x0 to 0x3FF.

[...]
 
radioStatus = xbee.set_pin_config(remoteDevice, XBeeZB::DIO2_AD2, Adc);
MBED_ASSERT(radioStatus == Success);
 
while(true) {
    uint16_t adc2_val;
     
    radioStatus = xbee.get_adc(remoteDevice, XBee802::DIO2_AD2, &adc2_val);
     
    MBED_ASSERT(radioStatus == Success);
     
    log_serial->printf("ADC2 value = 0x%04x\r\n", adc2_val);
     
    wait(5);
}
 
[...]

Setting the value (duty cycle) of a PWM¶

The example changes the analog value of PWM0 pin. The application walks through 0.0, 50.0, 70.0, 100.0 values every 5 seconds. If a led is connected to the PWM0 pin as shown in the schematic, it should change the intensity accordingly.

[...]
 
radioStatus = xbee.set_pin_config(remoteDevice, XBee802::PWM0, Pwm);
MBED_ASSERT(radioStatus == Success);
 
while(true) {
    static float pwm2_val_list[] = { 0.0, 50.0, 70.0, 100.0 };
    static uint8_t pwm2_val_idx = 0;
 
    log_serial->printf("Setting PWM0 to = %f\r\n", pwm2_val_list[pwm2_val_idx]);
 
    radioStatus = xbee.set_pwm(remoteDevice, XBee802::PWM0, pwm2_val_list[pwm2_val_idx]);
 
    MBED_ASSERT(radioStatus == Success);
 
    pwm2_val_idx++;
    if (pwm2_val_idx == sizeof(pwm2_val_list)/sizeof(pwm2_val_list[0])) {
        pwm2_val_idx = 0;
    }
     
    wait(5);
}
 
[...]