Latest revision as of 10:27, 26 September 2018

introduction

This manual describes the porting details of the ERIKA Enterprise v3 kernel(s) for the Atmel (now Microchip) families of microcontrollers which support 8/16-bit RISC AVR cores (aka AVR8).

AVR8 Features Supported

The following are the main features of the currently implemented support:

• Development tools
  • Support for AVR GCC compiler WinAVR
• Microcontrollers
  • Microchip AVR MCUs Families
    • Microchip ATmega328P Specific MCU.
• Evaluation Boards
  • Arduino Uno Board (ATmega328p)
• External Libraries
  • Full support for Arduino SDK 1.8.5;

Tutorials

The following tutorials are available for this architecture:

• AVR8: Arduino application build on Windows

Configuration and Programming

ERIKA Enterprise is configured through RT-Druid and an OIL file and some other properties.

The following sections describe the properties and OIL fields customized for Atmel (now Microchip) AVR8 architecture.

Compiler Path

It is possible to choose the path of the compiler in three different ways:

• Compiler specific environment variables: AVR_TOOLS
  • E.g.: AVR_TOOLS=C:\WinAVR
• RT-Druid Eclipse IDE Property.
• RT-Druid Configuration File Entry: preference_avr8__path_for_gcc_compiler
  • E.g.: preference_avr8__path_for_gcc_compiler=C:\WinAVR

Here is an example of RT-Druid configuration file.

Arduino SDK Path

It is possible to choose the path in three different ways:

• Specific environment variables: ARDUINO_SDK_FILES
  • E.g.: ARDUINO_SDK_FILES=C:\Program Files (x86)\Arduino
• RT-Druid Eclipse IDE Property.
• RT-Druid Configuration File Entry: preference_avr8__path_for_arduino_sdk
  • E.g.: preference_avr8__path_for_arduino_sdk=C:\Program Files (x86)\Arduino

Here is an example of RT-Druid configuration file.

Arduino Serial Port

It is possible to choose the Serial Port for Arduino in two different ways:

• RT-Druid Eclipse IDE Property.
• RT-Druid Configuration File Entry: preference_avr8__serial_port_for_arduino
  • E.g.: preference_avr8__serial_port_for_arduino=COM5

Here is an example of RT-Druid configuration file.

Arduino Serial Baudrate

It is possible to choose the Serial Baudrate for Arduino in two different ways:

• RT-Druid Eclipse IDE Property.
• RT-Druid Configuration File Entry: preference_avr8__serial_baudrate_for_arduino
  • E.g.: preference_avr8__serial_baudrate_for_arduino=115200

Here is an example of RT-Druid configuration file.

CPU

CPU_DATA must be set to AVR8.

The available COMPILER is GCC.

Example of a CPU_DATA section:

   CPU_DATA = AVR8 {
     COMPILER = GCC;
     ...
   };

MCU

MCU_DATA object supports for now the MEGA value only.

Example of a MCU_DATA section:

   MCU_DATA = MEGA {
     ...
   };

MODEL

MODEL attribute of MCU_DATA supports for now the MEGA_328p value only. Default value is MEGA_328p.

Example of MODEL attribute of a MCU_DATA section:

 MCU_DATA = MEGA {
   MODEL = MEGA_328p;
 };

BOARD

For now, there is no NATIVE board support for AVR8 Architecture. The ONLY supported board is Arduino by Arduino SDK 1.8.5.

NOTE: To support a custom board, it's mandatory to install the Arduino SDK software package and correctly set the related RT-Druid properties.

Moreover it's mandatory to set the F_CPU macro according to the CLOCK FREQUENCY set by custom AVR8 MCU Driver (e.g. 16MHz in the following example).

 ...
 OS myOs {
   ...
   CFLAGS = "-DF_CPU=16000000L";
   ...
 };
 ...

LIB

LIB object supports for now the ARDUINO value only.

Example of a LIB section:

   LIB = ARDUINO {
     ...
   };

ARDUINO

The following sections describe the OIL fields of the LIB object customized for the official ARDUINO SDK supports.

SDK_BOARD

SDK_BOARD attribute of ARDUINO supports for now the UNO value only. Default value is UNO.

Example of SDK_BOARD attribute of ARDUINO:

   LIB = ARDUINO {
     SDK_BOARD = UNO;
     ...
   };

VARIANT

VARIANT attribute of ARDUINO supports for now the CC value only. Default value is CC.

Example of VARIANT attribute of ARDUINO:

   LIB = ARDUINO {
     SDK_BOARD = UNO;
     VARIANT = CC;
     ...
   };

VERSION

VERSION attribute of ARDUINO CC VARIANT supports for now the "1.8.5" value only. Default value is "1.8.5".

Example of VERSION attribute of ARDUINO CC VARIANT:

   LIB = ARDUINO {
     SDK_BOARD = UNO;
     VARIANT = CC {
       VERSION = "1.8.5";
     };
     ...
   };

STAND_ALONE

STAND_ALONE boolean attribute of ARDUINO configures the build system to generate or not libarduinosdk.a stand-alone binary library. The default value is set to TRUE. Default value is TRUE.

Example of STAND_ALONE attribute of ARDUINO:

   LIB = ARDUINO {
     SDK_BOARD = UNO;
     VARIANT = CC {
       VERSION = "1.8.5";
     };
     STAND_ALONE = TRUE;
   };

Interrupt Handling

Interrupt Handling is microcontroller dependent so for each supported Atmel (now Microchip) AVR8 microcontroller family, the ISRs configuration of ERIKA Enterprise v3 is shown below.

MEGA Family

The MEGA family of AVR8 microcontrollers has an interrupt vector table which is stored in the flash memory. The lowest addresses of the interrupt vector table are allocated to the RESET and to the interrupt vectors. Interrupt handlers placed at lower addresses have higher hardware priorities than interrupt handlers placed at higher addresses so the PRIORITY attribute of the ISR object in the OIL is USELESS. The complete list of SOURCE entries is shown below.

• RESET: External Pin, Power-on Reset, Brown-out Reset and Watchdog System Reset
• INT0: External Interrupt Request 0
• INT1: External Interrupt Request 1
• PCINT0: Pin Change Interrupt Request 0
• PCINT1: Pin Change Interrupt Request 1
• PCINT2: Pin Change Interrupt Request 2
• WDT: Watchdog Time-out Interrupt
• TIMER2_COMPA: Timer/Counter2 Compare Match A
• TIMER2_COMPB: Timer/Counter2 Compare Match B
• TIMER2_OVF: Timer/Counter2 Overflow
• TIMER1_CAPT: Timer/Counter1 Capture Event
• TIMER1_COMPA: Timer/Counter1 Compare Match A
• TIMER1_COMPB: Timer/Coutner1 Compare Match B
• TIMER1_OVF: Timer/Counter1 Overflow
• TIMER0_COMPA: Timer/Counter0 Compare Match A
• TIMER0_COMPB: Timer/Counter0 Compare Match B
• TIMER0_OVF: Timer/Counter0 Overflow
• SPI_STC: SPI Serial Transfer Complete
• USART_RX: USART Rx Complete
• USART_UDRE: USART, Data Register Empty
• USART_TX: USART, Tx Complete
• ADC_ADC: Conversion Complete
• EE_READY: EEPROM Ready
• ANALOG_COMP: Analog Comparator
• TWI: 2-wire Serial Interface
• SPM_READY: Store Program Memory Ready

EEOPT

The following EEOPTs are specific of AVR8 Architecture:

• __AVR8_GCC_C99__: Enables C99 compiler option.

OSEK/VDX Extensions

This Section contains information about the OSEK/VDX Extensions (or optional features) that have been implemented for the AVR8 support.

System Timer

System Timer is microcontroller dependent so for each supported Atmel (now Microchip) AVR8 microcontroller family, the System Timer configuration of ERIKA Enterprise v3 is shown below.

MEGA Family

For the MEGA family of AVR8 microcontrollers the System Timer is linked to TIMER1 so the DEVICE attribute MUST be se to TIMER1_COMPA as shown below.

 COUNTER SystemTimer {
   MINCYCLE = 1;
   MAXALLOWEDVALUE = 65535;
   TICKSPERBASE = 1;
   TYPE = HARDWARE {
     DEVICE = "TIMER1_COMPA";
     SYSTEM_TIMER = TRUE;
   };
   SECONDSPERTICK = 0.001;
 };

Additional Notes

T.B.D.