UCOS AVR port context switching time

[artem]

ucos avr port

The context switching time was seen little bit long . It took about 80 usec to
make it .
Approximate measuring was done as :

spi_sendbyte(INT8U byte)
{

SPDR = byte
OSSemPend(spi_IsrSemaphore);
PORTB &= ~(0x80);
}


spi_UcosSpiIsrHandler(void)
{
PORTB |= 0x80;
OSSemPend(spi_IsrSemaphore);
}

SPI speed was set to highest so it took 2 usec to complete transfer .
Highest priority task was invoking the spi_sendbyte() and then .
Portb is set when SPI transfer complete is generated and reset after task resume when OSSemPend is returned .
UCOS works on Atmega128 Freq 16 MHz , external 64 SRAM .

Did somene measure UCOS context switch time and is it usual to have 80-100usec context switch under AVR ?

 

[artem]

avr ucos reset

If nobody is dealing with UCOS on AVR , i could chnage question to :

did someone measure UCOS context switching time and if so - what cointext switching time duration and what kind of processor and freq .

Regards

 

[thinkey]

context switching with avr

on ARM it take about 80 cycles