[Tinyos-help] Tmote CC2420 MAC payload length

[Erwing Sánchez]

---------- Forwarded message ----------
From: Erwing Sánchez <erwing.sanchez at gmail.com>
Date: May 10, 2007 2:41 PM
Subject: Re: [Tinyos-help] Tmote CC2420 MAC payload length
To: Ole Bischoff <bischoff at item.uni-bremen.de>


Hi,
I actually tryed that too. But it did not work, which I believe is
correct because I'm not working with TOS_msg. Instead, I create my own
'struct' which is similiar to the TOS_msg struct but with less control
fields. Besides, I do not use any component that implements something
like a send() command. Basically, I'm working on top of the
"HPLCC2420" component, which means that for sending I send directly
the bytes trhough the UART to the CC2420 TX-FIFO.
Thanks for your comment, if you have any other idea I'll really appreciate it.
Regards!
Erwing

On 5/10/07, Ole Bischoff <bischoff at item.uni-bremen.de> wrote:
>
>
>
>
> Hi Erwing,
>
>
>
> did you also changed (increased) TOSH_DATA_LENGTH in your Makefile? Because
> in most implementations of the send() command there is something like:
>
>
>
> command result_t Send.send[uint8_t id](TOS_MsgPtr _msg, uint16_t _length) {
>
>     TOS_MHopMsg* _mhopmsg = (TOS_MHopMsg*)_msg->data;
>
>     uint16_t _mhlength = offsetof(TOS_MHopMsg,data) + _length;
>
>
>
>     if (_mhlength > TOSH_DATA_LENGTH){
>
>       return FAIL;
>
>     }
>
>
>
> If a message is longer than TOSH_DATA_LENGTH it will be dropped. So if you
> didn't already consider this fact you'll have to adjust TOSH_DATA_LENGTH.
>
>
>
> Regards,
>
> OLE
>
>
>
>  ________________________________
>
>
> Von: tinyos-help-bounces at Millennium.Berkeley.EDU
> [mailto:tinyos-help-bounces at Millennium.Berkeley.EDU] Im
> Auftrag von Erwing Sánchez
>  Gesendet: Donnerstag, 10. Mai 2007 12:03
>  An: tinyos-help at Millennium.Berkeley.EDU
>  Betreff: [Tinyos-help] Tmote CC2420 MAC payload length
>
>
>
>
>
> Hi everybody:
>  I'm currently trying to develop a forward error correction algorithm above
> the IEEE 802.15.4 protocol stack of the CC2420 module in the Tmote Sky
> platform. Basically, I get rid of all TOS packets and go to the lowest level
> to work almost directly with the physical frame that is send through the
> CC2420 module.
>  So, I'm working with the frame that is shown in the CC2420 datasheet
> (http://www.chipcon.com/files/CC2420_Data_Sheet_1_3.pdf) in
> page 36. I'm getting a lot of trouble trying to send a full-length message,
> that is a 127-byte frame. Basically, I'm not able to send MAC payloads
> higher than 39 bytes... for some strange reason when I try to send 40 or
> more bytes in the MAC payload, the message does not go away!
>  Does anyone have any idea why this could be happening? I've been working on
> that for a couple of weeks and cannot find out anything!
>  Allow me to explain a little bit better how I'm implementing this
> experiment.
>  Basically, I'm working on top of the "HPLCC2420C" component that is part of
> the TinyOS distribution from Moteiv. As you probably know, within that
> component most of the CC2420 chip parameters may be defined (including
> internal control registers and physical frame fields). To tell you the
> truth, I reutilize most of the controlling parameters that are found in
> "CC2420ControlM" component, where CC2420 internal registers are configured.
>  I also create an structure for sending the package where I defined the
> following fields:
>  uint8_t length;
>  uint8_t fcfhi;
>  uint8_t fcflo;
>  uint8_t dsn;
>  uint16_t destpan;
>  uint16_t addr;
>  uint8_t *Data;
>
>  These fields are, essentially, the same as in the CC2420 datasheet.
>  As you can see, I use 8 bytes for controlling fields (length, fcfhi, fcflo,
> dsn, destpan, addr). According to CC2420 datasheet, I can use other 119
> bytes for MAC payload. However as I said before I'm able to send just 39
> bytes because for some reason it stops sending when I try to send a longer
> payload!!!
>  I'd really appreciate if you have any idea that I can use. Probably
> something that has to do with CC2420 configuration.
>  Thanks!
>  Erwing Sanchez
>
>
>
>
>
>
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