AVR-Chat

--- In AVR-Chat@yahoogroups.com, David Kelly <dkelly@...> wrote:
>
> On Tue, Jul 28, 2009 at 07:56:33AM -0700, hossein hashemi wrote:
> > your last paragraph made i read the data sheet again.
> > if data less than 32 bytes exp 25 bytes ,do you think it's transmitted after 30 ms?(pdf is not clear.)
> > it's pleasant for me.
> > 25 bytes as a 5 samples of one patient.but this 30ms,for monitoring, give a discrete state to data,isn't it? but i think i can use the static data for 30ms on monitor.
> > my baud rate is 4800bps.but the data sheet hasn't determined? which baud rate has this problem.? 
> > 
> > 
> > 
> > 
> > --- On Tue, 7/28/09, David Kelly <dkelly@...> wrote:
> > 
> > From: David Kelly <dkelly@...>
> > Subject: Re: [AVR-Chat] RF module
> > To: AVR-Chat@yahoogroups.com
> > Date: Tuesday, July 28, 2009, 6:21 PM
> > 
> > 
> > 
> > 
> > 
> > 
> > ?
> > 
> > 
> > 
> > 
> >     
> >                   On Tue, Jul 28, 2009 at 01:13:45PM -0000, iijfet wrote:
> > 
> > > hi,i wanna to use HM-TRS RF transceiver module,but i have a problem
> > 
> > > with it, i want to send a packet of data to it. The packet include 5
> > 
> > > bytes,& 60 packets come to RF (HM-TRS)per second,my baud rate is
> > 
> > > 4800bps.
> > 
> > > i read the data sheet of HM-TRS & attach its address for you.
> > 
> > > 
> > 
> > > http://www.hoperf. com/pdf/HM- TRS.pdf
> > 
> > > 
> > 
> > > you should know this RF module must accumulate  32 bytes for every
> > 
> > > sending of data. but the matter is :
> > 
> > > 
> > 
> > > has it at 4800bps continous performance or must accumulate 32 bytes?
> > 
> > > second state is unpleasant for me because of my data structure.
> > 
> > > this matter at its data sheet has not determined obviously.
> > 
> > 
> > 
> > You should read your own references:
> > 
> > - The module work mode is half duplex mode. The data will be immediately
> > 
> > - transmitted as soon as it accumulates 32 bytes in the serial port.
> > 
> > - When the data is less than 32 bytes, it will transmit again after
> > 
> > - 30ms. If the data is required to be sent out immediately, make sure it
> > 
> > - is at least 32 bytes.
> > 
> > 
> > 
> > It appears this RF module transmits every 30 mS then spends 5 mS
> > 
> > changing over to receive mode for a period (probably 20 mS) and then
> > 
> > another 5 mS back to transmit mode. So it is very likely there is no way
> > 
> > this RF module can produce the Real Time performance you are expecting.
> > 
> > 
> > 
> > Is not clear whether this unit transmits 30 mS after the last byte or 30
> > 
> > mS after the first byte of its 32 byte buffer. If after the first then
> > 
> > you will receive two of your 5 byte packets at a time.
> > 
> > 
> > 
> > -- 
> > 
> > David Kelly N4HHE, dkelly@HiWAAY. net
> > 
> > ============ ========= ========= ========= ========= ========= ========= ======
> > 
> > Whom computers would destroy, they must first drive mad.
> > 
> > 
> >  
> > 
> >       
> > 
> >     
> >     
> > 	
> > 	 
> > 	
> > 	
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 	
> > 
> > 
> > 	
> > 	
> > 
> > 
> >       
> > 
> > [Non-text portions of this message have been removed]
> 
> If you wish to participate in technical forums then you must unlearn bad
> email habits. Top-post without trim is poor manners. Trim all but the
> parts which relate to the contribution in your reply. Add your
> contributions immediately after the parts they relate to. Study the
> format of my previous replies and those of David VanHorn for examples.
> 
> The following is how *this* (my) reply should have been formed:
> 
> On Tue, Jul 28, 2009 at 07:56:33AM -0700, hossein hashemi wrote:
> > your last paragraph made i read the data sheet again. if data less
> > than 32 bytes exp 25 bytes ,do you think it's transmitted after 30
> > ms?(pdf is not clear.)
> 
> Yes, the data sheet is not clear. The module either transmits 30 mS
> after the first byte of data or 30 mS after the last byte of data, it
> does not say.
> 
> > it's pleasant for me.
> > 25 bytes as a 5 samples of one patient.but this 30ms,for monitoring,
> > give a discrete state to data,isn't it?
> 
> Am lost in your grammar.
> 
> Am a bit frightened that you are collecting data from patients.
> 
> You are collecting 5 bytes of data every 16.7 mS. We do not know if the
> module will transmit in the middle of your 3rd 5 byte packet or 7th 5
> byte packet. It will transmit in the middle of the 3rd if it measures 30
> mS from the first byte, or it will transmit in the middle of the 7th
> when the buffer contains 32 bytes if it is waiting for 30 mS of nothing
> before transmitting.
> 
> Either way it can not deliver your data every 16.7 mS, only once every
> 30 mS. Some of your data will have taken longer to arrive than others..
> 
> > but i think i can use the static data for 30ms on monitor. my baud
> > rate is 4800bps.but the data sheet hasn't determined? which baud rate
> > has this problem.? 
> 
> I don't understand "static data".
> 
> The data sheet says the RF module will keep up with constant stream of
> data at 9600 bps. That if you send faster than 9600 you have to slow the
> data, but on closer examination the module has no means of indicating
> that data is being sent too fast.
> 
> -- 
> David Kelly N4HHE, dkelly@...
> ========================================================================
> Whom computers would destroy, they must first drive mad.
>




ok,but i send  email from yahoo not group!i don't repeat again.
your reply is true.i must add a part to codevision for this problem or use another module.