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ben-wpan/atusb/fw2/board.c
Werner Almesberger e8b68041a5 atusb/fw2: autonomously restore the clock output settings after an RF reset
- atusb.c (main), board.c (set_clkm): moved CLKM initialization to
  board.c
- board.c (reset_rf): initialize the CLKM after each transceiver reset
2011-02-10 10:05:38 -03:00

54 lines
984 B
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);
}