Atmel launches  the ATtiny104 Xplained Nano evaluation kit, a nice way of introducing this $0.40 microcontroller.

ATtiny104_img

The small and low cost evaluation board includes an on-board programmer.

After received two boards from Digikey, started downloading the Atmel Studio.

ATTINY104_X.jpg

The Atmel Studio is a “BIG” tool and takes time for the installation, but after the waiting, everything went smooth.

I spent some time drawing the Pinout Diagram, it helps me to learn more about the mini development kit.

ATtiny104_IOe.jpg

In no time the ATtiny104 was reading the PUSH BUTTON and controlling the on board LED.

Attiny104_blinking.jpg

Next thing to do:  experimenting with the serial port.

The character ‘U’ is sent every 500 milliseconds if the BUTTON is pressed.

The working code  transmitting at 9600 bauds:


 

/* ATTINY104_Serial.c 
*  Created: 3/24/2016 08:20:00 PM 
*  Author : Ardunaut
* Program to test serial transmission. 
* While the BUTTON is pressed: 
* 'U' character is transmitted every 500 milliseconds. 
* The LED blinks when a char transmitted. 
* FOSC=1000000 :"After powering up the device or after a reset the system clock is automatically 
* set to calibrated internal 8MHz oscillator, divided by 8" (Datasheet pag.32) 
* Using C functions from: http://www.atmel.com/Images/Atmel-42505-8-bit-AVR-Microcontroller-ATtiny102-ATtiny104_Datasheet.pdf 
* Note: Zeros ('0') were removed from the register names to make the code compatible. 
                 __________
           VCC--|1       14|--GND (TPI CLK)
           PA0--|2       13|--PB3 (CDC TX) -->USART_Transmit()
(TPI DATA) PA1--|3       12|--PB2 (CDC RX) <--USART_Receive()
   (RESET) PA2--|4       11|--PB1 (BUTTON)
           PA3--|5       10|--PB0
           PA4--|6        9|--PA7
     (LED) PA5--|7        8|--PA6
                \__________/
        Atmel ATtiny104 Xplained Nano
  */ 

#include <avr/io.h>
#include <util/delay.h>

#define LED_PIN    (1 << PA5)
#define BUTTON_PIN (1 << PB1)
#define FOSC 1000000
#define BAUD 9600
#define MYUBRR FOSC/16/BAUD   //adding or subtracting 1 may be necessary.

void PORTS_init(void){  
  PUEB |= BUTTON_PIN;         // Enable Pull-Up function in PB1.
  PORTB |= BUTTON_PIN;        // Set Pull-Up for the Button.
  DDRA |= LED_PIN;            // Configure LED pin as Output.
} 

void USART_Init( unsigned int ubrr)
{
  /*Set baud rate */
  UBRRH = (unsigned char)(ubrr>>8);
  UBRRL = (unsigned char)ubrr;
  /*Enable receiver and transmitter */
  UCSRB = (1<<RXEN)|(1<<TXEN);
  /* Set frame format: 8data, 2stop bit */
  UCSRC = (1<<USBS)|(3<<UCSZ0);
  _delay_ms(250);
  PORTA |= LED_PIN;         // Switch off the LED.
  }
    
void USART_Transmit( unsigned char data )
{
  /* Wait for empty transmit buffer */
  while ( !( UCSRA & (1<<UDRE)) );
  /* Put data into buffer, sends the data */
  UDR = data;
}

unsigned char USART_Receive( void )
{
  /* Wait for data to be received */
  while ( !(UCSRA & (1<<RXC)) );
  /* Get and return received data from buffer */
  return UDR;
}

void USART_Flush( void )
{
  unsigned char dummy;
  while ( UCSRA & (1<<RXC) ) dummy = UDR;
}

/*----------------------------------------------------------------------------------------------------------------------------------------------------------*/
void main( void ){
  PORTS_init();
  USART_Init(MYUBRR);
  
  while(1){
    while(PINB & BUTTON_PIN){}  // Wait until the Button is pressed.
    PORTA &= ~LED_PIN;          // Switch on the LED.
    USART_Transmit( 'U' );
//    USART_Transmit( 85 );
    _delay_ms(50);
    PORTA |= LED_PIN;           // Switch off the LED.
    _delay_ms(450); 
  }
}

 

 

Some soldering to continue experimenting with the Xplained NANO in a breadboard.

ATtiny104_breadboard

ATtiny104_ready

Now, looking for an efficient code and low power solution to create an IoT node…

First, testing the hardware:

ATtiny104_RFcoms (1)


 

Transmitting at 300 bauds with the USART connected to the 433Mhz RF module:

ATtiny104_RF300


 

This is the code to transmit “HELLO” every second (while the button is pressed).

/* * ATTINY104_RF300.c 
* -Using the USART for 300 bauds transmission with the RF Module (433Mhz). 
* -Tree 0xAA bytes are sent as preamble of the message to balance the receptor. 
* -While the BUTTON is pressed "HELLO" message is transmitted every second aprox. 
* -Characters are separated 50 milliseconds (20 milliseconds of mark). 
* -The LED is ON during the message is transmission. 
* -FOSC= 1000000 : "After powering up the device or after a reset the system clock is automatically 
*  set to calibrated internal 8MHz oscillator, divided by 8" (Datasheet pag.32) 
* -Using C functions from: http://www.atmel.com/Images/Atmel-42505-8-bit-AVR-Microcontroller-ATtiny102-ATtiny104_Datasheet.pdf 
* -Note: Zeros ('0') were removed from the register names to make the code compatible. 
* -Created: 3/26/2016 07:25:00 PM 
* -Author : Ardunaut
                 __________
           VCC--|1       14|--GND (TPI CLK)
           PA0--|2       13|--PB3 (CDC TX) -->USART_Transmit()
(TPI DATA) PA1--|3       12|--PB2 (CDC RX) <--USART_Receive()
   (RESET) PA2--|4       11|--PB1 (BUTTON)
           PA3--|5       10|--PB0
           PA4--|6        9|--PA7
     (LED) PA5--|7        8|--PA6
                \__________/
        Atmel ATtiny104 Xplained Nano  
*/ 

#include <avr/io.h>
#include <util/delay.h>

#define LED_PIN    (1 << PA5)
#define BUTTON_PIN (1 << PB1)
#define FOSC 1000000 // Clock Speed 
#define BAUD 300     
#define MYUBRR FOSC/16/BAUD-1

void PORTS_init(void){  
  PUEB |= BUTTON_PIN;         // Enable Pull-Up function in PB1.
  PORTB |= BUTTON_PIN;        // Set Pull-Up for the Button.
  DDRA |= LED_PIN;            // Configure LED pin as Output.
} 

void USART_Init( unsigned int ubrr){
  //Set baud rate:
  UBRRH = (unsigned char)(ubrr>>8);
  UBRRL = (unsigned char)ubrr;
  //Enable receiver and transmitter:
  UCSRB = (1<<RXEN)|(1<<TXEN);
  // Set frame format: 8data, 2stop bit :
  UCSRC = (1<<USBS)|(3<<UCSZ0);
  _delay_ms(250);
  PORTA |= LED_PIN;         // Switch off the LED.
  }
    
void USART_Transmit( unsigned char data ){
  // Wait for empty transmit buffer:
  while ( !( UCSRA & (1<<UDRE)) );
  // Put data into buffer, sends the data:
  UDR = data;
}

unsigned char USART_Receive( void ){
  // Wait for data to be received:
  while ( !(UCSRA & (1<<RXC)) );
  // Get and return received data from buffer :
  return UDR;
}

void USART_Flush( void ){
  unsigned char dummy;
  while ( UCSRA & (1<<RXC) ) dummy = UDR;
}
/*----------------------------------------------------------------------------------------------------------------------------------------------------------*/
void main( void ){
  PORTS_init();
  USART_Init(MYUBRR);
  
  while(1){
    while(PINB & BUTTON_PIN){}  // Wait until the Button is pressed.
    PORTA &= ~LED_PIN;          // Switch on the LED.
    
    USART_Transmit( 0xAA );   // To balance the receptor.
    _delay_ms(50);
    USART_Transmit( 0xAA );   // To balance the receptor.
    _delay_ms(50);    
    USART_Transmit( 0xAA );   // To balance the receptor.
    _delay_ms(50);
    USART_Transmit( 'H' );
    _delay_ms(50);
    USART_Transmit( 'E' );
    _delay_ms(50);
    USART_Transmit( 'L' );
    _delay_ms(50);
    USART_Transmit( 'L' );
    _delay_ms(50);
    USART_Transmit( 'O' );    

    PORTA |= LED_PIN;         // Switch off the LED.
    _delay_ms(650);           // delay to complete one second.
  }
}

More experiments and learning …

blogger-at-work

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