AVR XMega Getting Started IO Ports USART

University of Florida, EEL 5666: IMDL © Drs. Arroyo & Schwartz

IMDL Software Series

University of Florida, EEL-5666 © Drs. A. A. Arroyo & E. M. Schwartz 1

Atmel AVR Xmega Code Getting Started with ASF,

I/O Ports & USART

A. A. Arroyo



Today’s Menu • Getting Started with Atmel ASF in AVR

Studio 5 for the Epiphany DIY Board • General Purpose I/O Pins • Serial I/O




AVR Studio 5 & Atmel ASF Creating new ASF Projects using AVR Studio 5

for the Epiphany DIY Board(s) Step 1: Select Open New Project on the AVR Studio 5 Opening Screen

or alternatively select New>Project from the File Menu (ctrl+shift+n)



AVR Studio 5 & Atmel ASF Step 2: Select Users Boards, User application template – User Board

XMEGA – A and enter a name for your project and select a directory for your project in the New Project Window. Hit OK when ready.




AVR Studio 5 & Atmel ASF Step 3: Select ATmega64A1 in the device selection window (Epiphany

DIY uses the ATmega64A1). Hit OK.



AVR Studio 5 & Atmel ASF Step 4: Open the Project Properties (alt-F7) & select Generate Hex Files

by checking the appropriate check box.




AVR Studio 5 & Atmel ASF Step 6: Add path “..” Toolchain Directories section. Hit OK.



AVR Studio 5 & Atmel ASF Step 7: Add symbol “F_CPU=32000000” to the Toolchain Symbols

section. Hit OK




AVR Studio 5 & Atmel ASF Step 8: Import init.c & user_board.h and [lcd.h, motor.h] which are

used by user_board.h from Tim’s Project.



AVR Studio 5 & Atmel ASF Step 9: Start writing your code by modifying main.c and creating any

“.c” and “.h” files as appropriate.

#include <asf.h> #include <avr/io.h> #include <stdio.h>

int main(void) { board_init(); // initialize the DIY Board // TODO place your initialization code here while(1) { // Main Loop //TODO write your main loop code here

} }




AVR Studio 5 & Atmel ASF • The first example will use GPIO pins to toggle

external LEDs connected to pins PC0 & PC1 • Import the IOPORT from the ASF Library • In directory src/asf/xmega/drivers/ioport the

system imports ioport.c and ioport.h • In file ioport.h, after the macro: #define IOPORT_CREATE_PIN(port, pin) ((PORT_##port) + (pin)) add the following macro (for convenience):

`

#define IOPORT_CREATE_ID(port) ((PORT_##port) / 8

See project ASF_IOPORT



AVR Studio 5 & Atmel ASF • If you wish to use GPIO functions, add the GPIO

service from the ASF Library. The GPIO service requires ioport.h and most of the GPIO functions actually call the corresponding IOPORT functions in the ASF Library

• The second example uses the GPIO functions in lieu of the IOPORT functions

See project ASF_GPIO




®  Type “xmega usart” into Google

®  The first result is a nice 7-page document explaining EXACTLY how to set up the serial USART on the Xmega. The source code for this example is easily found on the internet.



USART




USART



USART


























®  Here is the register summary for the USART. We can see that serial communication requires the use of 7 registers ®  1 for data ®  1 for status ®  3 for control ®  2 for baud rate

USART






USART

• The third example uses the USART functions in conjunction with the IOPORT functions

See project ASF_USART

• If you wish to use Tim’s USART functions, then import uart.c and uart.h from Tim’s Software

• The ISR for the USART is uart.c and it can be modified as needed.

See project ASF_USART Change the include in main.c to <uart.h>




The End!

AVR XMega Getting Started IO Ports USART

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