6、射频前端设置功能实现

\qquad 下面是HD-GR GNSS导航软件的射频前端设置功能实现代码：

// spi_max2769.c -- RF front end setting functions.

/* 
 * Copyright (C) 2005 Andrew Greenberg
 * Distributed under the GNU GENERAL PUBLIC LICENSE (GPL) Version 2 (June 1991).
 * See the "COPYING" file distributed with this software for more information.
 */

/* 
 * HD-GR GNSS receiver project
 * Modes    : None
 * version  : V1.0
 * date     : xx/xx/2015
 */

#include <io.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include "includes.h"
#include "system.h"
#include "altera_avalon_pio_regs.h"
#include "alt_types.h"
#include "altera_avalon_spi.h"
#include "spi_max2769.h"

//#define spi_max2769_2_config_GPS_L1
#define spi_max2769_2_config_lna_off

#ifdef spi_max2769_2_config_GPS_L1

// max2769 spi config for GPS L1
alt_u32 spi_max2769_config[10] = {
    
    
#ifdef spi_max2769_2_config_lna_off
	MAX2769_CONF1_LNAOFF,
#else
	MAX2769_CONF1_NORMAL,	// CONF1	// 0xA2919A3
#endif // spi_max2769_config_lnamode_off
     0x0550288,	// CONF2	// 0x0550288
     0xEAFE1DC,	// CONF3	// 0xEAFF1DC
     0x9EC0008,	// PLLCONF	// 0x9EC0008
     0x0C00080,	// DIV,		// 0x0C00080 (GPS)
     0x8000070,	// FDIV		// 0x8000070
     0x8000000,	// STRM		// 0x8000000
     0x10061B2,	// CLK		// 0x10061B2
     0x1E0F401,	// TEST1	// 0x1E0F401
     0x14C0402};// TEST2	// 0x14C0402

#else

//max2769 spi config for BD B1
alt_u32 spi_max2769_config[10] = {
    
    
#ifdef spi_max2769_2_config_lna_off
	MAX2769_CONF1_LNAOFF,
#else
	MAX2769_CONF1_NORMAL,	// CONF1	// 0xA2919A3
#endif // spi_max2769_config_lnamode_off
		0x055028C,	// CONF2
		0xEAFE1DC,	// CONF3
		0x9EC0008,	// PLLCONF
		0x0BE4080,	// DIV,BD1:0x0BE4080
		0x0000070,	// FDIV,L1和BD1:0x00000705
		0x8000000,	// STRM
		0x10061B2,	// CLK
		0x1E0F401,	// TEST1
		0x14C0402};	// TEST2

#endif // spi_max2769_2_config_GPS_L1

void spi_max2769_2_init(void)
{
    
    
	// 设置SPI的control寄存器: 0xc0即bit6=1, bit7=1
	//   bit6 ITRDY置1则为发送就绪状态使能中断
	//   bit7 IRRDY置1则为接收就绪状态使能中断
	IOWR_32DIRECT(SPI_MAX2769_2_BASE, 12, 0xc0);

	// SPI的status寄存器清零: 0x60即bit5=0, bit6=0
	//   bit5 TMT 传输移位寄存器空标志。（主机模式下）当TMT=0时表示一次传输
	//        正在进行。TMT=1表示移位寄存器空。
	//   bit6 TRDY发送等待。TRDY=1表示txdata寄存器空，可以发起新的一次写入。
	IOWR_32DIRECT(SPI_MAX2769_2_BASE, 8, 0x60);
}

void spi_max2769_2_write(alt_u8 addr, alt_u32 cfg)
{
    
    
	alt_u8 wdata[4];
	wdata[0] = (cfg >> 20) & 0xFF;
	wdata[1] = (cfg >> 12) & 0xFF;
	wdata[2] = (cfg >> 4) & 0xFF;
	wdata[3] = ((cfg << 4) & 0xF0) | (addr & 0x0F);
	alt_avalon_spi_command(SPI_MAX2769_2_BASE, 0, 4, wdata, 0, 0, 0);
}

void spi_max2769_2_setup(void)
{
    
    
	alt_u8 addr;
	for (addr = 0; addr < 10; addr ++) {
    
    
		spi_max2769_2_write(addr, spi_max2769_config[addr]);
	}
}