crashtest-r0ket/firmware/funk/openbeacon.c

#include <stdint.h>
#include "funk/openbeacon.h"
#include "funk/nrf24l01p.h"
#include "basic/byteorder.h"
#include "sysdefs.h"
#include "filesystem/ff.h"

const uint32_t key[4] = {0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF};
const uint8_t useencryption = 0;
const uint8_t mac[5] = {1,2,3,2,1};

uint32_t oid = 0;
uint32_t seq = 0;
uint8_t strength = 0;

void openbeaconSave()
{
    FIL file;
    BYTE buf[4];
    UINT readbytes;

    if( f_open(&file, "beacon", FA_OPEN_ALWAYS|FA_WRITE) )
        return;

    uint32touint8p(seq, buf);

    if( f_write(&file, buf, 4, &readbytes) )
        return; 

    f_close(&file);
}

void openbeaconRead()
{
    FIL file;
    BYTE buf[4];
    UINT readbytes;

    if( f_open(&file, "beacon", FA_OPEN_EXISTING|FA_READ) )
        return;

    if( f_read(&file, buf, 4, &readbytes) )
        return;
    seq = uint8ptouint32(buf);
    
    f_close(&file);
}


void openbeaconSetup(uint32_t id)
{
    oid = id;
    strength = 0;
    openbeaconRead();
}

uint8_t openbeaconSendPacket(uint32_t id, uint32_t seq,
        uint8_t flags, uint8_t strength)
{
    uint8_t buf[32];

    buf[0]=0x10; // Length: 16 bytes
    buf[1]=0x17; // Proto - fixed at 0x17?
    buf[2]=flags;
    buf[3]=strength*85; // Send intensity

    uint32touint8p(seq, buf+4);
    uint32touint8p(id, buf+8);

    buf[12]=0xff; // salt (0xffff always?)
    buf[13]=0xff;

    return nrf_snd_pkt_crc_encr(32,buf,useencryption?key:NULL);
}

uint8_t openbeaconSend(void)
{
    uint8_t status;
    nrf_set_strength(strength);
    nrf_set_tx_mac(sizeof(mac), mac);

    status = openbeaconSendPacket(oid, seq++, 0xFF, strength++);
    if( strength == 4 )
        strength = 0;
    if( seq % OPENBEACON_SAVECOUNTER  == 0 )
        openbeaconSave();
    return status;
}