twr with sleep

Hi
i am trying to use sleep mode , with TWR. After completion of ranging, i let dw1000 go into sleep mode and wait for a few tens of ms to wake up with spi.Although dw1000 can wake up,but the distance measured is wrong. I had to reinitialize the parameters of dw1000 after dw1000 woke up to normal range(this wastes a lot of time on initialization).Is it the wrong way for dw1000 to go to sleep?
/config sleep mode/
dwt_configuresleep(DWT_PRESRV_SLEEP | DWT_CONFIG | AON_WCFG_ONW_LLDE , DWT_WAKE_CS | DWT_SLP_EN);
while(1){
//TWR CODE
/* Put DW1000 to sleep. /
dwt_entersleep();
delay(100);//100ms delay
/
Wake DW1000 up. See NOTE 2 below. */
dwt_spicswakeup(dummy_buffer, DUMMY_BUFFER_LEN);

}
[color=#333333]Thanks in advance, regards.[/color]

resolved,after wake up, must be softrest it.

how to softrest it.please tell me the register