中文手冊:(的Atmega 324A)http://www.atmel.com/images/Atmel-8272-8-bit-AVR-microcontroller-ATmega164A_PA-324A_PA-644A_PA-1284_P_datasheet.pdfAVR(324A的Atmega)DAC經由SPI接口
中文手冊:(DAC)http://www.ti.com/lit/ds/symlink/dac101s101.pdf
您好!!
我在c學習嵌入式編程,所以請耐心等待。
我正嘗試使用通過SPI連接到ATmega324A的DAC(DAC101S101)生成一個波形。 Dac是單向的。現在我只是試圖從dac獲得輸出。我已經做了一個我將用來獲得所需的正弦波。另外,如何調製波的頻率? (比如讓說,4000Hz的)(另外我連接了外部振盪器到的ATmega芯片。)
i Have connected:
PB5 -- MOSI -------> DIN (DAC)
PB7 -- SCK -------> SCK (DAC)
PA1 --------------->#Sync(DAC)
void init_SPI_Master(void) {
/*
* Set MOSI and SCK output, all others input
* DDR_SPI = (1<<DD_MOSI)| (1<<DD_SCK);
*
* (for ATmega 324A
*
* DDRB = (1<<DDB5) | (1<<DDB7)
*
*/
DDRB = (1<<5) | (1<<7);
/*
*Enable SPI, Master, set clock rate fck/16;
*
*/
SPCR0 = (1<<SPE0) | (1<< MSTR0) | (1<<SPR00) | (1<<CPOL0);
}
void Tx_SPI_Master (unsigned char data) {
/*
* Start transmition
*
*/
SPDR0 = data;
/*
* is Tx complete ?
*
*/
}
int main(void)
{
unsigned char data1 = 0x04;
unsigned char data2 = 0xFC;
DDRA = 1 << 1;
PORTA = 1 << 1;
init_SPI_Master();
while(1)
{
//TODO:: Please write your application code
//sync: i'm not sure as how to provide sync to the dac
// according to the datasheet as soon as the sync bit goes low the
// register starts accepting data into Din.
// so right now i am trying to input 0000001111111100 into
// the dac.
PORTA = 1 << PINA1;
PORTA = 0 << PINA1;
Tx_SPI_Master(data1);
Tx_SPI_Master(data2);
}
}
謝謝!!!!
大多數微控制器都可以選擇關閉SPI中的自動/ SS功能,在這種情況下,該引腳將成爲GPIO。所以唯一需要的「位元音」應該是/ SS引腳本身。 – Lundin