cc2420.c

zigbee 协议堆栈 stack（简化协议）

#include "cc2420.h"

void cc2420_init(void) {	
  
  spi_init();

  P4DIR |= BV(CSN) | BV(VREG_EN) | BV(RESET_N);

  SPI_DISABLE();                /* Unselect radio. */
}

/*
 * On the Tmote Sky access to I2C/SPI/UART0 must always be
 * exclusive. 
 */

/*
 * Initialize SPI bus.
 */
void spi_init(void) {
  
  static unsigned char spi_inited = 0;

  if (spi_inited)
    return;

  /* Initalize ports for communication with SPI units. */

  U0CTL  = CHAR + SYNC + MM + SWRST; /* SW  reset,8-bit transfer, SPI master */
  U0TCTL = CKPH + SSEL1 + STC;		 /* Data on Rising Edge, SMCLK, 3-wire. */

  U0BR0  = 0x02;		/* SPICLK set baud = SMCLK/2 => 250000Hz */
  U0BR1  = 0;  		    /* Dont need baud rate control register 2 - clear it */
  U0MCTL = 0;			/* Dont need modulation control. */

  P3SEL |= BV(SCK) | BV(MOSI) | BV(MISO); /* Select Peripheral functionality */
  P3DIR |= BV(SCK) | BV(MISO);			  /* Configure as outputs(SIMO,CLK). */

  ME1 |= USPIE0;          	/* USART SPI module enable */
  U0CTL &= ~SWRST;      	/* SW Reset Cleared, SPI Ready */
			
  IE1 |= (UTXIE0 | URXIE0); /* Enable Transmit and Receive Interrupts */
}