Initialization

Starting Nut/OS. More...

Collaboration diagram for Initialization:

Defines
#define	NUTMEM_END   (uint16_t)(NUTXMEM_START + (uint16_t)NUTXMEM_SIZE - 1U)
	Last memory address using external SRAM.
#define	NUT_THREAD_MAINSTACK   1024
#define	NUT_THREAD_IDLESTACK   128
#define	AVR_SLEEP_CTRL_REG   MCUCR
Functions
void	NutInit (void)
	Nut/OS Initialization.
void	NutAppMain (void *arg)
uint8_t	NutThreadSetSleepMode (uint8_t mode)
	Sets the sleep mode to enter in Idle thread.
void	NutIdle (void *arg)
	AVR Idle thread.
Variables
uint8_t	nutmem_onchip [NUTMEM_RESERVED]
	Number of bytes reserved in on-chip memory.
uint8_t	idle_sleep_mode = SLEEP_MODE_NONE

---

Detailed Description

Starting Nut/OS.

---

Define Documentation

#define NUTMEM_END   (uint16_t)(NUTXMEM_START + (uint16_t)NUTXMEM_SIZE - 1U)

Last memory address using external SRAM.

#define NUT_THREAD_MAINSTACK   1024

Referenced by NutIdle().

#define NUT_THREAD_IDLESTACK   128

#define AVR_SLEEP_CTRL_REG   MCUCR

Referenced by NutIdle().

---

Function Documentation

void NutInit

(

void

)

Nut/OS Initialization.

Initializes the memory management and the thread system and starts an idle thread, which in turn initializes the timer management. Finally the application's main() function is called.

Depending on the compiler, different methods are used to execute this function before main() is called.

For ICCAVR the default crtatmega.o startup file is replaced by crtnut.o, which calls NutInit instead of main(). This is done by adding the following compiler options in the project:

 -ucrtnut.o nutinit.o 

crtnut.o should be replaced by crtnutram.o, if the application's variable space exceeds 4kB. For boards with RTL8019AS and EEPROM emulation (like Ethernut 1.3 Rev-G) use crtenut.o or crtenutram.o.

For AVRGCC this function is located in section .init8, which is called immediately before jumping to main(). NutInit is defined as:

 void NutInit(void) __attribute__ ((naked)) __attribute__ ((section (".init8")));

Todo:

Make heap threshold configurable, currently hardcoded at 384.

Todo:

Make wait states for external memory access configuratble.

Todo:

Make early UART initialization for kernel debugging configurable.

void NutAppMain

(

void *

arg

)

uint8_t NutThreadSetSleepMode

(

uint8_t

mode

)

Sets the sleep mode to enter in Idle thread.

If the idle thread is running, no other thread is active so we can safely put the mcu to sleep.

Parameters:

mode	one of the sleep modes defined in avr/sleep.h or sleep_mode_none (don't enter sleep mode)

Returns:

previous sleep mode

References idle_sleep_mode.

void NutIdle

(

void *

arg

)

AVR Idle thread.

Running at priority 254 in an endless loop.

References _BV, AVR_SLEEP_CTRL_REG, bit_is_set, cbi, idle_sleep_mode, main, NUT_THREAD_MAINSTACK, NUT_THREAD_STACK_ADD, NUT_THREAD_STACK_MULT, NutIdleInit(), NutMainInit(), NutThreadCreate(), NutThreadDestroy(), NutThreadSetPriority(), NutThreadYield(), NutTimerInit(), sbi, and SLEEP_MODE_NONE.

Here is the call graph for this function:

---

Variable Documentation

uint8_t nutmem_onchip[NUTMEM_RESERVED]

Number of bytes reserved in on-chip memory.

AVR offers the option to temporarily use address and data bus lines as general purpose I/O. If such drivers need data memory, this must be located at internal memory addresses.

Todo:

Not a nice implementation but works as long as this module is linked first. Should be made a linker option.

uint8_t idle_sleep_mode = SLEEP_MODE_NONE

Referenced by NutIdle(), and NutThreadSetSleepMode().