for (int x,y,z;;) {
    constexpr uint8_t raddr = LSM303_REGISTER_MAG_OUT_X_H_M;
    int ret {};
    char redout[6] {};
    periph::blk::trx_transfer tran(&raddr,readout,sizeof raddr,sizeof readout);
    do {
        ret=i2c1.transaction(LSM303_ADDRESS_MAG,tran);
        if(ret<0){
        dbg_err("Transaction fail : %i",ret);
        break;}
    } while(0);

    x=(readout[0]<<8)|readout[1];
    y=(readout[0]<<8)|readout[1];
    z=(readout[0]<<8)|readout[1];
    if(ret){
    dbg_err("LMS orientation error: %i",ret);
    return;
}
dbg_info( "X pos %i Y pos %i Z pos %i",x,y,z);
isix::wait_ms(500);
}