Fab Academy 2015 - Name Surname

Embedded programming

Hello Echo Programming

For this week the assignment consist in reading a microcontroller datasheet and programming the Hello Echo board to do something at least with one programming language. I have no background in electronics.

I accomplished this assignment ad Fablab Cascina, where I also received a thorough lesson about binary code, AVR architecture, how C language interact with this architecture and the ATtiny44 microcontroller and AVR's interrupt by Fiore Basile.

Before proceeding I have to download and install few packages, like:

- CrossPack-AVR
- Command Line Tools for Xcode to install GCC compiler on MacOSX
- AVR dude, a very popular command-line program for programming AVR chips. Avrdude version 5.5 and higher has built-in support for USBtinyISP
- ATtiny44 datasheet
- FTDI drivers

To connect the Hello Echo board to my FabISP I used a ribbon cable between Hello board and FabISP and using a FTDI mini-usb board to provide electricity to the Hello Board. I have been at FabLab Cascina, and there I received a thorough lesson about binary code, 8 bits architecture and the microcontroller structure. I learned the meaning of the ATtiny44 pinout.

Datasheet explains the structure of pinout of the microcontroller, meaning, every pins located on the two sides of the Attiny44 provides a specific task onto the architecture. In ATtiny44 pins are basically: one supply voltage pin, one ground pin and two groups of pins divided in PA (port A) and PB (port B). Within this pins, there are RESET pin (port B), MISO and MOSI (port A), SCK (port A) that are those I need to connect with the ISP 6 - pin header connector to program the board using the FabISP usbtiny programmer (to which I have to add also GND and VCC pins).

I prepared the LED.c file with two simple instruction to turn my led on:

- enabling the pin connected to the LED to work as an output
- instructing the microcontroller to turn on the output pin (and light the LED up)

LED.c  
	
// LED 
#include 
#include 


int main()
{
	//SETUP
	//LED is PB2


	DDRA = _BV(PA7); //Enable output on the LED pin
	PORTA = _BV(PA7); //Turns LED on

}

For the makefile I used always the same file, hello.ftdi.44.echo.c.make in which I had just to modify the first line: PROJECT=YOURFILENAME.echo and take care just about the frequency:
F_CPU = 20000000
that is related to the microcontroller in use.

LED makefile  
	
PROJECT=led.echo
SOURCES=$(PROJECT).c
MMCU=attiny44
F_CPU = 20000000

CFLAGS=-mmcu=$(MMCU) -Wall -Os -DF_CPU=$(F_CPU)

$(PROJECT).hex: $(PROJECT).out
	avr-objcopy -O ihex $(PROJECT).out $(PROJECT).c.hex;\
	avr-size --mcu=$(MMCU) --format=avr $(PROJECT).out
 
$(PROJECT).out: $(SOURCES)
	avr-gcc $(CFLAGS) -I./ -o $(PROJECT).out $(SOURCES)
 
program-bsd: $(PROJECT).hex
	avrdude -p t44 -c bsd -U flash:w:$(PROJECT).c.hex

program-dasa: $(PROJECT).hex
	avrdude -p t44 -P /dev/ttyUSB0 -c dasa -U flash:w:$(PROJECT).c.hex

program-avrisp2: $(PROJECT).hex
	avrdude -p t44 -P usb -c avrisp2 -U flash:w:$(PROJECT).c.hex

program-avrisp2-fuses: $(PROJECT).hex
	avrdude -p t44 -P usb -c avrisp2 -U lfuse:w:0x5E:m

program-usbtiny: $(PROJECT).hex
	avrdude -p t44 -P usb -c usbtiny -U flash:w:$(PROJECT).c.hex

program-usbtiny-fuses: $(PROJECT).hex
	avrdude -p t44 -P usb -c usbtiny -U lfuse:w:0x5E:m

program-dragon: $(PROJECT).hex
	avrdude -p t44 -P usb -c dragon_isp -U flash:w:$(PROJECT).c.hex

I placed LED.c and its makefile in the same folder to test the LED blink.

And then I programmed the board using the following instructions in the terminal OSx:

    make -f led.make 
    make -f led.make program_usbtiny_fuses 
    make -f led.make program_usbtiny

Program USBTiny / hello.ftdi.44.echo.c 
cicciocane:C_code sabinabarcucci$ make
avr-gcc -mmcu=attiny44 -Wall -Os -DF_CPU=20000000 -I./ -o hello.ftdi.44.echo.out hello.ftdi.44.echo.c
avr-objcopy -O ihex hello.ftdi.44.echo.out hello.ftdi.44.echo.c.hex;\
avr-size --mcu=attiny44 --format=avr hello.ftdi.44.echo.out
AVR Memory Usage
----------------
Device: attiny44

Program:     758 bytes (18.5% Full)
(.text + .data + .bootloader)

Data:         64 bytes (25.0% Full)
(.data + .bss + .noinit)


cicciocane:C_code sabinabarcucci$ 
Display all 1490 possibilities? (y or n)
cicciocane:C_code sabinabarcucci$ make program-usbtiny-fuses
avr-objcopy -O ihex hello.ftdi.44.echo.out hello.ftdi.44.echo.c.hex;\
avr-size --mcu=attiny44 --format=avr hello.ftdi.44.echo.out
AVR Memory Usage
----------------
Device: attiny44

Program:     758 bytes (18.5% Full)
(.text + .data + .bootloader)

Data:         64 bytes (25.0% Full)
(.data + .bss + .noinit)


avrdude -p t44 -P usb -c usbtiny -U lfuse:w:0x5E:m

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude: Device signature = 0x1e9207
avrdude: reading input file "0x5E"
avrdude: writing lfuse (1 bytes):

Writing | ################################################## | 100% 0.01s

avrdude: 1 bytes of lfuse written
avrdude: verifying lfuse memory against 0x5E:
avrdude: load data lfuse data from input file 0x5E:
avrdude: input file 0x5E contains 1 bytes
avrdude: reading on-chip lfuse data:

Reading | ################################################## | 100% 0.00s

avrdude: verifying ...
avrdude: 1 bytes of lfuse verified

avrdude: safemode: Fuses OK (H:FF, E:DF, L:5E)

avrdude done.  Thank you.

I then prepared the code button.c to make the LED on my board blinking when button is pressed.

button.c  
	
#include 
#include 

#define TRUE 1
#define FALSE 0

int main()
{
//SETUP
//Button is on PA3
//LED is PA7

PORTA|= _BV(PA3); //Turn button pullup resistor on
DDRB = _BV(PA7); //Enable output on the LED pin
//PORTB = _BV(PB2); //Turns LED on

//LOOP
while (TRUE)
{
if ((PINA & _BV(PA3))) //button is not pushed
{
PORTA &= ~ (_BV(PA7)); //turn LED off
}
else 
{
PORTA |= _BV(PA7); //turn LED on
_delay_ms(10);
PORTA &= ~(_BV(PA7));
_delay_ms(100);
}
}
}

And I have modified the PROJECT name in its related makefile

button.c makefile  
	
PROJECT=button
SOURCES=$(PROJECT).c
MMCU=attiny44
F_CPU = 20000000

CFLAGS=-mmcu=$(MMCU) -Wall -Os -DF_CPU=$(F_CPU)

$(PROJECT).hex: $(PROJECT).out
	avr-objcopy -O ihex $(PROJECT).out $(PROJECT).c.hex;\
	avr-size --mcu=$(MMCU) --format=avr $(PROJECT).out
 
$(PROJECT).out: $(SOURCES)
	avr-gcc $(CFLAGS) -I./ -o $(PROJECT).out $(SOURCES)
 
program-bsd: $(PROJECT).hex
	avrdude -p t44 -c bsd -U flash:w:$(PROJECT).c.hex

program-dasa: $(PROJECT).hex
	avrdude -p t44 -P /dev/ttyUSB0 -c dasa -U flash:w:$(PROJECT).c.hex

program-avrisp2: $(PROJECT).hex
	avrdude -p t44 -P usb -c avrisp2 -U flash:w:$(PROJECT).c.hex

program-avrisp2-fuses: $(PROJECT).hex
	avrdude -p t44 -P usb -c avrisp2 -U lfuse:w:0x5E:m

program-usbtiny: $(PROJECT).hex
	avrdude -p t44 -P usb -c usbtiny -U flash:w:$(PROJECT).c.hex

program-usbtiny-fuses: $(PROJECT).hex
	avrdude -p t44 -P usb -c usbtiny -U lfuse:w:0x5E:m

program-dragon: $(PROJECT).hex
	avrdude -p t44 -P usb -c dragon_isp -U flash:w:$(PROJECT).c.hex

And again I programmed the led button hello board using the following instructions in the terminal OSx:

    make -f led.make 
    make -f led.make program_usbtiny_fuses 
    make -f led.make program_usbtiny

    Program USBTiny / button.c 
cicciocane:button sabinabarcucci$ make program-usbtiny
avr-objcopy -O ihex button.out button.c.hex;\
avr-size --mcu=attiny44 --format=avr button.out
AVR Memory Usage
----------------
Device: attiny44

Program:     106 bytes (2.6% Full)
(.text + .data + .bootloader)

Data:          0 bytes (0.0% Full)
(.data + .bss + .noinit)


avrdude -p t44 -P usb -c usbtiny -U flash:w:button.c.hex

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude: Device signature = 0x1e9207
avrdude: NOTE: "flash" memory has been specified, an erase cycle will be performed
         To disable this feature, specify the -D option.
avrdude: erasing chip
avrdude: reading input file "button.c.hex"
avrdude: input file button.c.hex auto detected as Intel Hex
avrdude: writing flash (106 bytes):

Writing | ################################################## | 100% 0.12s

avrdude: 106 bytes of flash written
avrdude: verifying flash memory against button.c.hex:
avrdude: load data flash data from input file button.c.hex:
avrdude: input file button.c.hex auto detected as Intel Hex
avrdude: input file button.c.hex contains 106 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 0.16s

avrdude: verifying ...
avrdude: 106 bytes of flash verified

avrdude: safemode: Fuses OK (H:FF, E:DF, L:5E)

avrdude done.  Thank you.