Many thanks for your reply. It's really the issue and good to know.

Ittipong

2009/5/5 Philip Levis <[email protected]>

> If there's an SFD before the timer fires, your code will reset the timer to
> fire. E.g., imagine your mote has an SFD interrupt every 500ms. It will set
> the timer to fire in 1024ms, the SFD goes again, it will reset the timer to
> fire in 1024ms, the SFD goes again...
>
> I don't know if that's the root of your problem, but it's definitely an
> issue.
>
> Phil
>
>
> On Apr 23, 2009, at 2:42 AM, Ittipong Khemapech wrote:
>
>  I start the timer within the receive() event and *nothing* happens. No
>> packet is transmitted by the source. I'm pretty sure that the radio is on at
>> that time.
>>
>> I posted this problem several weeks ago and still got no reply. That's why
>> I have to use the InitW2RTimer and it's started in the receivedSFD() event.
>>
>> Anybody got the same experience?
>>
>> Thanks,
>> Ittipong
>>
>>
>> 2009/4/21 Ittipong Khemapech <[email protected]>
>> It wasn't me asking about the previous Timer questions. Many thanks for
>> your hints. Will try and get back soon.
>>
>> Ittipong
>>
>> 2009/4/21 Michael Schippling <[email protected]>
>>
>> I guess this is what you were trying to get at in previous
>> Timer questions, right?
>>
>> It looks like it should work the way you want. The only thing
>> I can see that is questionable is the long atomic {block} for
>> your message sending in DataSendTimer.fired(). This might
>> block interrupts for too long.
>>
>> I would try to simplify the Timer scheme on it's own, flashing
>> LEDs or something to see if it works the way you expect, and then
>> start adding the radio message drivers back in.
>>
>> I think you should also be able to use the receive() method instead
>> of starting your first timer, because it is called after the message
>> is fully received.
>>
>> MS
>>
>> Ittipong Khemapech wrote:
>> Hi,
>>
>> I have been trying to figure the problems out for days. No idea what
>> causes it.
>>
>> I have a source receiving a packet from the base station. After the SFD is
>> received, a timer is called to run to make sure that the reception is
>> completed. The source waits for a wait_interval duration to send its data
>> packet. So, another timer is used for timing the transmission.
>>
>> I am using AlarmToTimer component. The command startOneShot is called.
>> What I expect is that the source should send *only after* it receives the
>> packet from base station. It seems to me that the source keeps sending.
>>
>> Look forward to hear from you soon.
>>
>> Thanks,
>> Ittipong
>>
>> The codes are as follows:
>>
>> MyDef.h
>>
>> ---------------------------------------------------------------------------------------------------
>>
>> #ifndef MYDEF_H_
>> #define MYDEF_H_
>>
>> enum {
>>  WAIT_TO_RECEIVE = 1024
>> };
>>
>> #endif
>> ==================================================
>>
>> SourceAppC.nc
>>
>> ----------------------------------------------------------------------------------------------------
>>
>> #include "MyDef.h"                   #include "DataMsg.h"
>> #include "ControlMsg.h"
>>
>> configuration SourceAppC {
>> }
>> implementation {
>>  components MainC;
>>  components ActiveMessageC;
>>
>>  components new AMSenderC(AM_DATAMSG) as AMSenderDataC;
>>  components new AMReceiverC(AM_CONTROLMSG) as AMReceiverCtrlC;
>>
>>  components new Alarm32khz32C() as Alarm2Timer;
>>  components new AlarmToTimerC(T32khz) as W2RTimer;             components
>> new AlarmToTimerC(T32khz) as SendTimer;
>>
>>  components CC2420TransmitC;
>>  components CC2420ActiveMessageC;
>>
>>  components SourceC as App;
>>
>>  // Wiring
>>  App.Boot -> MainC;
>>
>>  App.Packet -> AMSenderDataC;
>>  App.AMPacket -> AMSenderDataC;
>>  App.AMSend -> AMSenderDataC;
>>  App.Receive -> AMReceiverCtrlC;
>>
>>  App.AMControl -> ActiveMessageC;;
>>
>>  App.InitW2RTimer -> W2RTimer;     App.DataSendTimer -> SendTimer;
>>   W2RTimer.Alarm -> Alarm2Timer;
>>  SendTimer.Alarm -> Alarm2Timer;
>>               App.CC2420Packet -> CC2420ActiveMessageC;
>>  App.RadioTimeStamping -> CC2420TransmitC;
>>  App.CC2420Transmit -> CC2420TransmitC;
>>     }
>> =====================================================
>>
>> SourceC.nc
>>
>> ----------------------------------------------------------------------------------------------------------
>>
>> #include <Timer.h>
>> #include "MyDef.h"                   #include "DataMsg.h"
>> #include "ControlMsg.h"
>>
>> module SourceC {
>>  uses {
>>     interface Boot;
>>     interface AMSend;
>>     interface Receive;                         interface AMPacket;
>>     interface Packet;
>>     interface Timer<T32khz> as InitW2RTimer;
>>     interface Timer<T32khz> as DataSendTimer;
>>     interface RadioTimeStamping;             interface SplitControl as
>> AMControl;
>>     interface CC2420Packet;                         interface
>> CC2420Transmit;
>>  }
>> }
>> implementation {
>>  message_t dpkt, cpkt;
>>  bool sending = FALSE;
>>  uint16_t pktseq, sentpkts;                 uint8_t current_tx;
>>                                                        uint8_t base_addr,
>> me;
>>  uint32_t no_slot, slot_length, slot_start;         uint32_t
>> wait_interval;
>>
>>  uint16_t rcv_no;
>>
>>  task void callInitW2RTimer() {
>>     call InitW2RTimer.startOneShot(WAIT_TO_RECEIVE);
>>  }
>>
>>  task void callDataSendTimer() {
>>     call DataSendTimer.startOneShot(wait_interval);
>>  }
>>
>>  event void Boot.booted() {
>>     call AMControl.start();
>>  }
>>
>>  event void AMControl.startDone(error_t err) {
>>     if (err != SUCCESS) {
>>         call AMControl.start();
>>     }
>>  }
>>
>>  event void AMControl.stopDone(error_t err) {
>>  }
>>
>>  event void InitW2RTimer.fired() {
>>     post callDataSendTimer();
>>  }
>>  event void DataSendTimer.fired() {
>>
>>     if (!sending) {
>>         atomic {
>>
>>             DataMsg* dataMsg = (DataMsg*)(call Packet.getPayload(&dpkt,
>> NULL));
>>
>>             sentpkts++;
>>             pktseq++;
>>
>>             call CC2420Packet.setPower(&dpkt, MAX_TX);
>> current_tx = call CC2420Packet.getPower(&dpkt);
>>             dataMsg->pkt_type = 1;
>>             dataMsg->source_id = me;
>>             dataMsg->rcv_no = rcv_no;
>>
>>             dataMsg->tx_power = current_tx;
>>             dataMsg->snt_no = sentpkts;
>>             dataMsg->seq_no = pktseq;
>>             dataMsg->slot = no_slot;
>>             dataMsg->length = slot_length;
>>             dataMsg->start = slot_start;
>>             dataMsg->wait = wait_interval;
>>
>>             if (call AMSend.send(base_addr, &dpkt, sizeof(DataMsg)) ==
>> SUCCESS) {
>>                 sending = TRUE;                     }
>>         }
>>     }
>>
>>  }
>>  event void AMSend.sendDone(message_t *msg, error_t error) {
>>     if (&dpkt == msg) {
>>         atomic {
>>             sending = FALSE;
>>         }             }
>>  }
>>  event message_t* Receive.receive(message_t* msg, void* payload, uint8_t
>> len) {
>>
>>     if (len == sizeof(ControlMsg)) {
>>         atomic {
>>               ControlMsg* controlMsg = (ControlMsg*) payload;
>>
>>             base_addr = controlMsg->base_id;
>>             me = TOS_NODE_ID;
>>
>>             rcv_no = controlMsg->snt_no;
>>
>>             no_slot = controlMsg->no_alloc_slot;
>>             slot_length = controlMsg->slot_length;
>>             slot_start = controlMsg->slot_start;
>>
>>             wait_interval = (uint32_t) (((me - 1) * slot_length) +
>> slot_start);
>>
>>         }
>>     }
>>     return msg;
>>  }
>>
>>
>>  async event void RadioTimeStamping.transmittedSFD(uint16_t time,
>> message_t* p_msg) {
>>  }
>>
>>  async event void RadioTimeStamping.receivedSFD(uint16_t time) {
>>     post callInitW2RTimer();           }
>>
>>  async event void CC2420Transmit.sendDone(message_t* p_msg, error_t error)
>> {
>>  }
>>
>> }
>> ====================================================================
>>
>>
>>
>>
>> ------------------------------------------------------------------------
>>
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>
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