nrf905.c和nrf905.h怎么写？

nrf905.c和nrf905.h是nRF905无线收发器的驱动程序文件，以下是简单的示例代码：

nrf905.h

#ifndef __NRF905_H
#define __NRF905_H

#include <stdint.h>

#define NRF905_CHANNEL_MAX 83

typedef struct {
    uint8_t *tx_buf;
    uint8_t *rx_buf;
    uint32_t tx_buf_size;
    uint32_t rx_buf_size;
    uint8_t channel;
    uint32_t spi_speed_hz;
    uint8_t spi_mode;
    uint8_t ce_pin;
    uint8_t txen_pin;
    uint8_t pwr_pin;
} nrf905_t;

int nrf905_init(nrf905_t *dev);
int nrf905_set_channel(nrf905_t *dev, uint8_t channel);
int nrf905_set_tx_address(nrf905_t *dev, uint8_t *address);
int nrf905_send(nrf905_t *dev, uint8_t *data, uint32_t len);
int nrf905_receive(nrf905_t *dev, uint8_t *data, uint32_t len);

#endif /* __NRF905_H */

nrf905.c

#include "nrf905.h"
#include "spi.h"
#include "gpio.h"

#define NRF905_SPI_MODE_0 0
#define NRF905_SPI_MODE_1 1
#define NRF905_SPI_MODE_2 2
#define NRF905_SPI_MODE_3 3

#define NRF905_COMMAND_R_REGISTER    0x00
#define NRF905_COMMAND_W_REGISTER    0x20
#define NRF905_COMMAND_R_RX_PAYLOAD  0x61
#define NRF905_COMMAND_W_TX_PAYLOAD  0xA0
#define NRF905_COMMAND_FLUSH_TX      0xE1
#define NRF905_COMMAND_FLUSH_RX      0xE2
#define NRF905_COMMAND_REUSE_TX_PL   0xE3
#define NRF905_COMMAND_R_RX_PL_WID   0x60
#define NRF905_COMMAND_W_ACK_PAYLOAD 0xA8
#define NRF905_COMMAND_W_TX_PAYLOAD_NOACK 0xB0
#define NRF905_COMMAND_NOP           0xFF

#define NRF905_CONFIG_PWR_OFF    0x00
#define NRF905_CONFIG_PWR_ON     0x02
#define NRF905_CONFIG_CRC_8      0x00
#define NRF905_CONFIG_CRC_16     0x04
#define NRF905_CONFIG_CRC_EN     0x08
#define NRF905_CONFIG_CRC_DIS    0x00
#define NRF905_CONFIG_LONG_RANGE 0x00
#define NRF905_CONFIG_SHORT_RANGE 0x40
#define NRF905_CONFIG_MODE_RX    0x00
#define NRF905_CONFIG_MODE_TX    0x20
#define NRF905_CONFIG_HZ_433_92  0x00
#define NRF905_CONFIG_HZ_868_00  0x10
#define NRF905_CONFIG_HZ_915_00  0x20

#define NRF905_STATUS_RX_DR      0x40
#define NRF905_STATUS_TX_DS      0x20
#define NRF905_STATUS_MAX_RT     0x10

static int nrf905_write_register(nrf905_t *dev, uint8_t reg, uint8_t val);
static int nrf905_read_register(nrf905_t *dev, uint8_t reg, uint8_t *val);
static int nrf905_spi_transfer(nrf905_t *dev, uint8_t *tx_buf, uint8_t *rx_buf, uint32_t len);

int nrf905_init(nrf905_t *dev)
{
    int ret = 0;

    ret |= gpio_init(dev->ce_pin, GPIO_MODE_OUTPUT);
    ret |= gpio_init(dev->txen_pin, GPIO_MODE_OUTPUT);
    ret |= gpio_init(dev->pwr_pin, GPIO_MODE_OUTPUT);

    gpio_write(dev->ce_pin, 0);
    gpio_write(dev->txen_pin, 0);
    gpio_write(dev->pwr_pin, 1);

    uint8_t config = NRF905_CONFIG_PWR_ON | NRF905_CONFIG_CRC_16 | NRF905_CONFIG_CRC_EN | NRF905_CONFIG_LONG_RANGE | NRF905_CONFIG_MODE_RX | NRF905_CONFIG_HZ_433_92;
    ret |= nrf905_write_register(dev, NRF905_COMMAND_W_REGISTER | 0x00, config);
    ret |= nrf905_set_channel(dev, dev->channel);

    return ret;
}

int nrf905_set_channel(nrf905_t *dev, uint8_t channel)
{
    if (channel > NRF905_CHANNEL_MAX) {
        return -1;
    }

    dev->channel = channel;
    return nrf905_write_register(dev, NRF905_COMMAND_W_REGISTER | 0x01, channel);
}

int nrf905_set_tx_address(nrf905_t *dev, uint8_t *address)
{
    return nrf905_write_register(dev, NRF905_COMMAND_W_REGISTER | 0x10, address[0]) ||
           nrf905_write_register(dev, NRF905_COMMAND_W_REGISTER | 0x11, address[1]) ||
           nrf905_write_register(dev, NRF905_COMMAND_W_REGISTER | 0x12, address[2]) ||
           nrf905_write_register(dev, NRF905_COMMAND_W_REGISTER | 0x13, address[3]) ||
           nrf905_write_register(dev, NRF905_COMMAND_W_REGISTER | 0x14, address[4]);
}

int nrf905_send(nrf905_t *dev, uint8_t *data, uint32_t len)
{
    gpio_write(dev->ce_pin, 0);
    gpio_write(dev->txen_pin, 1);

    int ret = nrf905_write_register(dev, NRF905_COMMAND_W_TX_PAYLOAD, data[0]);
    for (int i = 1; i < len; i++) {
        ret |= nrf905_write_register(dev, NRF905_COMMAND_W_TX_PAYLOAD_NOACK, data[i]);
    }

    gpio_write(dev->ce_pin, 1);

    uint8_t status;
    int timeout = 100000;
    do {
        nrf905_read_register(dev, NRF905_COMMAND_R_REGISTER | 0x07, &status);
        if (--timeout == 0) {
            ret = -1;
            break;
        }
    } while (!(status & NRF905_STATUS_TX_DS));

    gpio_write(dev->txen_pin, 0);

    nrf905_write_register(dev, NRF905_COMMAND_FLUSH_TX, 0);

    return ret;
}

int nrf905_receive(nrf905_t *dev, uint8_t *data, uint32_t len)
{
    gpio_write(dev->ce_pin, 0);

    int ret = nrf905_write_register(dev, NRF905_COMMAND_FLUSH_RX, 0);

    gpio_write(dev->ce_pin, 1);

    uint8_t status;
    int timeout = 100000;
    do {
        nrf905_read_register(dev, NRF905_COMMAND_R_REGISTER | 0x07, &status);
        if (--timeout == 0) {
            ret = -1;
            break;
        }
    } while (!(status & NRF905_STATUS_RX_DR));

    gpio_write(dev->ce_pin, 0);

    ret |= nrf905_read_register(dev, NRF905_COMMAND_R_RX_PAYLOAD, data);

    return ret;
}

static int nrf905_write_register(nrf905_t *dev, uint8_t reg, uint8_t val)
{
    uint8_t tx_buf[2] = {reg, val};
    uint8_t rx_buf[2];

    return nrf905_spi_transfer(dev, tx_buf, rx_buf, 2);
}

static int nrf905_read_register(nrf905_t *dev, uint8_t reg, uint8_t *val)
{
    uint8_t tx_buf[2] = {reg, 0xFF};
    uint8_t rx_buf[2];

    int ret = nrf905_spi_transfer(dev, tx_buf, rx_buf, 2);

    *val = rx_buf[1];

    return ret;
}

static int nrf905_spi_transfer(nrf905_t *dev, uint8_t *tx_buf, uint8_t *rx_buf, uint32_t len)
{
    spi_init(dev->spi_speed_hz, dev->spi_mode);

    gpio_write(dev->ce_pin, 0);

    int ret = spi_transfer(tx_buf, rx_buf, len);

    gpio_write(dev->ce_pin, 1);

    return ret;
}

注意，以上代码中的gpio_init()和gpio_write()函数是GPIO控制相关的函数，spi_init()和spi_transfer()函数是SPI总线控制相关的函数，这些函数的实现需要根据具体的硬件平台进行编写。