/* Copyright (c) 2009 Nordic Semiconductor. All Rights Reserved.
 *
 * The information contained herein is property of Nordic Semiconductor ASA.
 * Terms and conditions of usage are described in detail in NORDIC
 * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
 *
 * Licensees are granted free, non-transferable use of the information. NO
 * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
 * the file.
 *
 */
/** @file
* @addtogroup nrf_dev_radio_rx_example_main nrf_dev_radio_tx_example_main
* @{
*/
 
#include "radio_config.h"
#include "nrf_delay.h"

/* These are set to zero as Shockburst packets don't have corresponding fields. */
#define PACKET_S1_FIELD_SIZE      (0UL)  /**< Packet S1 field size in bits. */
#define PACKET_S0_FIELD_SIZE      (0UL)  /**< Packet S0 field size in bits. */
#define PACKET_LENGTH_FIELD_SIZE  (0UL)  /**< Packet length field size in bits. */

/**
 * @brief Function for swapping/mirroring bits in a byte.
 * 
 *@verbatim
 * output_bit_7 = input_bit_0
 * output_bit_6 = input_bit_1
 *           :
 * output_bit_0 = input_bit_7
 *@endverbatim
 *
 * @param[in] inp is the input byte to be swapped.
 *
 * @return
 * Returns the swapped/mirrored input byte.
 */
static uint32_t swap_bits(uint32_t inp);

/**
 * @brief Function for swapping bits in a 32 bit word for each byte individually.
 * 
 * The bits are swapped as follows:
 * @verbatim
 * output[31:24] = input[24:31] 
 * output[23:16] = input[16:23]
 * output[15:8]  = input[8:15]
 * output[7:0]   = input[0:7]
 * @endverbatim
 * @param[in] input is the input word to be swapped.
 *
 * @return
 * Returns the swapped input byte.
 */
static uint32_t bytewise_bitswap(uint32_t inp);

static uint32_t swap_bits(uint32_t inp)
{
    uint32_t i;
    uint32_t retval = 0;
    
    inp = (inp & 0x000000FFUL);
    
    for (i = 0; i < 8; i++)
    {
        retval |= ((inp >> i) & 0x01) << (7 - i);     
    }
    
    return retval;    
}


static uint32_t bytewise_bitswap(uint32_t inp)
{
      return (swap_bits(inp >> 24) << 24)
           | (swap_bits(inp >> 16) << 16)
           | (swap_bits(inp >> 8) << 8)
           | (swap_bits(inp));
}


/** 
 * @brief Function for configuring the radio to operate in Shockburst compatible mode.
 * 
 * To configure the application running on nRF24L series devices:
 *
 * @verbatim
 * uint8_t tx_address[5] = { 0xC0, 0x01, 0x23, 0x45, 0x67 };
 * hal_nrf_set_rf_channel(7);
 * hal_nrf_set_address_width(HAL_NRF_AW_5BYTES); 
 * hal_nrf_set_address(HAL_NRF_TX, tx_address);
 * hal_nrf_set_address(HAL_NRF_PIPE0, tx_address); 
 * hal_nrf_open_pipe(0, false);
 * hal_nrf_set_datarate(HAL_NRF_1MBPS);
 * hal_nrf_set_crc_mode(HAL_NRF_CRC_16BIT);
 * hal_nrf_setup_dynamic_payload(0xFF);
 * hal_nrf_enable_dynamic_payload(false);
 * @endverbatim
 *
 * When transmitting packets with hal_nrf_write_tx_payload(const uint8_t *tx_pload, uint8_t length),
 * match the length with PACKET_STATIC_LENGTH.
 * hal_nrf_write_tx_payload(payload, PACKET_STATIC_LENGTH);
 * 
*/
void radio_configure()
{
    // Radio config
    NRF_RADIO->TXPOWER   = (RADIO_TXPOWER_TXPOWER_0dBm << RADIO_TXPOWER_TXPOWER_Pos);
    NRF_RADIO->FREQUENCY = 7UL;  // Frequency bin 7, 2407MHz
    NRF_RADIO->MODE      = (RADIO_MODE_MODE_Nrf_1Mbit << RADIO_MODE_MODE_Pos);

    // Radio address config
    NRF_RADIO->PREFIX0 = 
        ((uint32_t)swap_bits(0xC3) << 24) // Prefix byte of address 3 converted to nRF24L series format
      | ((uint32_t)swap_bits(0xC2) << 16) // Prefix byte of address 2 converted to nRF24L series format
      | ((uint32_t)swap_bits(0xC1) << 8)  // Prefix byte of address 1 converted to nRF24L series format
      | ((uint32_t)swap_bits(0xC0) << 0); // Prefix byte of address 0 converted to nRF24L series format
  
    NRF_RADIO->PREFIX1 = 
        ((uint32_t)swap_bits(0xC7) << 24) // Prefix byte of address 7 converted to nRF24L series format
      | ((uint32_t)swap_bits(0xC6) << 16) // Prefix byte of address 6 converted to nRF24L series format
      | ((uint32_t)swap_bits(0xC4) << 0); // Prefix byte of address 4 converted to nRF24L series format

    NRF_RADIO->BASE0 = bytewise_bitswap(0x01234567UL);  // Base address for prefix 0 converted to nRF24L series format
    NRF_RADIO->BASE1 = bytewise_bitswap(0x89ABCDEFUL);  // Base address for prefix 1-7 converted to nRF24L series format
  
    NRF_RADIO->TXADDRESS   = 0x00UL;  // Set device address 0 to use when transmitting
    NRF_RADIO->RXADDRESSES = 0x01UL;  // Enable device address 0 to use to select which addresses to receive

    // Packet configuration
    NRF_RADIO->PCNF0 = (PACKET_S1_FIELD_SIZE     << RADIO_PCNF0_S1LEN_Pos) |
                       (PACKET_S0_FIELD_SIZE     << RADIO_PCNF0_S0LEN_Pos) |
                       (PACKET_LENGTH_FIELD_SIZE << RADIO_PCNF0_LFLEN_Pos); //lint !e845 "The right argument to operator '|' is certain to be 0"

    // Packet configuration
    NRF_RADIO->PCNF1 = (RADIO_PCNF1_WHITEEN_Disabled << RADIO_PCNF1_WHITEEN_Pos) |
                       (RADIO_PCNF1_ENDIAN_Big       << RADIO_PCNF1_ENDIAN_Pos)  |
                       (PACKET_BASE_ADDRESS_LENGTH   << RADIO_PCNF1_BALEN_Pos)   |
                       (PACKET_STATIC_LENGTH         << RADIO_PCNF1_STATLEN_Pos) |
                       (PACKET_PAYLOAD_MAXSIZE       << RADIO_PCNF1_MAXLEN_Pos); //lint !e845 "The right argument to operator '|' is certain to be 0"

    // CRC Config
    NRF_RADIO->CRCCNF = (RADIO_CRCCNF_LEN_Two << RADIO_CRCCNF_LEN_Pos); // Number of checksum bits
    if ((NRF_RADIO->CRCCNF & RADIO_CRCCNF_LEN_Msk) == (RADIO_CRCCNF_LEN_Two << RADIO_CRCCNF_LEN_Pos))
    {
        NRF_RADIO->CRCINIT = 0xFFFFUL;   // Initial value      
        NRF_RADIO->CRCPOLY = 0x11021UL;  // CRC poly: x^16+x^12^x^5+1
    }
    else if ((NRF_RADIO->CRCCNF & RADIO_CRCCNF_LEN_Msk) == (RADIO_CRCCNF_LEN_One << RADIO_CRCCNF_LEN_Pos))
    {
        NRF_RADIO->CRCINIT = 0xFFUL;   // Initial value
        NRF_RADIO->CRCPOLY = 0x107UL;  // CRC poly: x^8+x^2^x^1+1
    }
}

/** 
 * @}
 */
