So habe nun alles zusammengebaut und fogendes steht in der anleitung von meinem modul:
Spi command:

Command | function
0xa0 | return current humidity reading (8bit signed number) in %RH
0xb0 | return current temperature reading (8bit signed number) in °C
0xc0 | return system status, returns 0xaf when system is idle


Recieved command | return value | descriptions

0xb0 | 0xee | the current temperature reading has gone beyond the measuring range
0xb0 | 0xf5 | the current temperature is -11°c
0xb0 | 0x10 | the current temperature is 16°c
0xa0 | 0x32 | the current humdity is 50%RH
0xc0 | 0xaf | system is in idle

Note:
1. The sck frequency of spi interface shall be in range from 3khz to 2mhz.
2. /cs is low level only when spi interface communication is in process and shall be in high level in any other situations.
3. The interval of two successive commands shall be greater than 0.2s.


selber habe ich nun das hier probiert in der controllib.c
Code:
// External Temperatur/Feuchtmodul-Modul:

int SPI_temp_readByte(void)
{
	uint8_t data;
	PORTB &= ~MEM_CS2;
	writeSPI(0xb0);
	mSleep(200);
	data = readSPI();
	PORTB |= MEM_CS2;
	return data;
}
im programm:
Code:
data = SPI_temp_readByte();
und diese fehlermeldung kommt dann.(wird trotzdem ohne schwere fehler compiliert).

warning: implicit declaration of function 'SPI_temp_readByte'[/code]