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ben-wpan/atusb/fw2/board.c
Werner Almesberger f8fbb02bb0 atusb/fw2: further abstract board functions
- atusb.c (main), board.h (board_init), board.c (board_init): moved
  clock and I/O initialization to board file
- board.h (led), board.c (led), atusb.c (main): abstracted LED setting
  in function "led" instead of open-coding it
- spi.c (spi_init): set nSS to 1 before enabling the output, so that we
  don't generate what looks like an empty SPI transaction
2011-02-10 20:49:23 -03:00

78 lines
1.3 KiB
C

#include <stdint.h>
#include <avr/io.h>
#define F_CPU 8000000UL
#include <util/delay.h>
#include "at86rf230.h"
#include "board.h"
#include "spi.h"
static void set_clkm(void)
{
/* switch CLKM to 8 MHz */
/*
* @@@ Note: Atmel advise against changing the external clock in
* mid-flight. We should therefore switch to the RC clock first, then
* crank up the external clock, and finally switch back to the external
* clock. The clock switching procedure is described in the ATmega32U2
* data sheet in secton 8.2.2.
*/
spi_begin();
spi_send(AT86RF230_REG_WRITE | REG_TRX_CTRL_0);
spi_send(CLKM_CTRL_8MHz);
spi_end();
}
void reset_rf(void)
{
/* AT86RF231 data sheet, 12.4.13, reset pulse width: 625 ns (min) */
CLR(nRST_RF);
_delay_us(1);
SET(nRST_RF);
/* 12.4.14: SPI access latency after reset: 625 ns (min) */
_delay_us(1);
/* we must restore TRX_CTRL_0 after each reset (9.6.4) */
set_clkm();
}
uint8_t read_irq(void)
{
return PIN(IRQ_RF);
}
void led(int on)
{
if (on)
SET(LED);
else
CLR(LED);
}
void board_init(void)
{
/* We start with a 1 MHz/8 clock. Disable the prescaler. */
CLKPR = 1 << CLKPCE;
CLKPR = 0;
/* set up all the outputs; default port value is 0 */
OUT(LED);
OUT(nRST_RF); /* resets the transceiver */
OUT(SLP_TR);
}