Response time for TRF 7970

Nanda -

The question seems like a simple one, but since alot of variables in the timings are allowed, it is not quite an easy answer as it completely depends on the ISO Standard card/tag device being interacted with and the command begin sent or responded to. And since the timings are dictated by the ISO standards, they are what they are. For example, with ISO15693 high tag data rate, it takes about 1.5mSec to send command out and about 4.5mSec to get response. (this is the easy one to use as example) I did the attached doc a few years back and correlated it with the timings listed in the back of all the Feig user manuals.

6266.Tag-It HF-I Timing_Rev1.pdf

However, for ISO14443B example, the data rates start at 106kbps and can go up to 848kbps and the standard allows for a variable frame wait time integer, so the response is allowed to be up to almost 5 seconds later from the command being sent out. Type A might be a little easier to figure out, since the most popular of those devices stay at 106kbps, but to be honest i have not done this timing study of those.  

The bottom line here is that the over the air time can be calculated for any standard or card type possible, but since there are so many, if you could narrow it down then you could figure out the exact time it would take, based on those card requirements.

Thanks for the information Josh

As my experiment goes i dont want an initiator to send a commant to the target and get the command back to the initiator. I want target to send the data continiously and the initiator to recive it all the time.

Is that possible?? i dont want to use DirectMode 0 or 1. I want to use current setup and acheive it by changing the software code.

Regards

Nanda

Nanda -

your brief explanation seems a little reversed from how it works. An initiator is exactly that, otherwise how will the target know when/how to send data back?

Josh

Thats exactly what i wanted to do. It is like using Direct Mode 0, I dont want the initiator to turn on the transmitter instead i want the transmitter to be ON all the time and send the data to the receiver.

Nanda

Nanda -

What you are describing is possible I think, but this description you have given (sounds like an active beacon of some sort) is quite unique. What is the application? How does any other device sync up with this one and then retrieve the data in correct order/timing?  

Josh

My project is to identify right vehicle among many vehicles. I wanted to transmit some 10Bites of data from the vehcile and that data must be read by the loops placed on the ground ( Receiver) . It is some thing like Tranmitter always transmits and Receiver always Recives. The receiver unit must be pre defined that it can read the vehicle data and display on hyperterminal showing the vehicle information. This project is more of like identifying the vehicle.

I have another question about Active Mode in TRF7970. I have seen information on passive targets in the datasheet for TRF7970 but not much on active mode. Can you please let me how and which registers to tweak to make the unit work on active mode. I prefer working on active mode than using passive as range is another issue if i work on passive.

Nanda

Nanda -

I do not think that the HF technology is the correct one here for your application since the description you are giving makes reference to loops in the ground and implies some longer distance requirement that what is realistically possible with HF technology the and the presence of a vehicle (which is quite a bit of metal, moving). I would recommend that you have a look at our extensive line of low frequency (134.2kHz) RFID devices. This product line is made for and has a long history of working in this sort of application. We offer completed tags which are preprogrammed with just 64 bit serial #, devices you can program your own 80 bit serial #, as well as devices with much more user memory (208 & 1360 bits, plus 64 bit serial #). We also offer the reader and antenna solutions as well - but i would imagine you would be making your own ground loops, which is not difficult to do.

For the reader side, have a look at the RI-STU-251B (which is complete housed reader) or the modules RI-RFM-007B/-008B to be used with either RI-CTL-MB2B (since you said you wanted to use HyperTerminal, this control module uses RS-232)

http://focus.ti.com/docs/prod/folders/print/ri-stu-251b.html?qgpn=ri-stu-251b

http://focus.ti.com/docs/prod/folders/print/ri-rfm-007b.html?qgpn=ri-rfm-007b + http://focus.ti.com/docs/prod/folders/print/ri-ctl-mb2b.html?qgpn=ri-ctl-mb2b

Housed LF antennas are here ==> http://focus.ti.com/paramsearch/docs/parametricsearch.tsp?family=rfid&sectionId=475&tabId=2104&familyId=1354&paramCriteria=no

LF Tags are here ==>  http://focus.ti.com/paramsearch/docs/parametricsearch.tsp?family=rfid&sectionId=475&tabId=2102&familyId=1352 , just choose 134.2kHz in the parametric selection table and you will see all the devices available.

You could also see this app note i wrote (which was for waste management RFID technology selection, but you can use for your own basic understanding here) 

Nanda -

I do not think that the HF technology is the correct one here for your application since the description you are giving makes reference to loops in the ground and implies some longer distance requirement that what is realistically possible with HF technology the and the presence of a vehicle (which is quite a bit of metal, moving). I would recommend that you have a look at our extensive line of low frequency (134.2kHz) RFID devices. This product line is made for and has a long history of working in this sort of application. We offer completed tags which are preprogrammed with just 64 bit serial #, devices you can program your own 80 bit serial #, as well as devices with much more user memory (208 & 1360 bits, plus 64 bit serial #). We also offer the reader and antenna solutions as well - but i would imagine you would be making your own ground loops, which is not difficult to do.

For the reader side, have a look at the RI-STU-251B (which is complete housed reader) or the modules RI-RFM-007B/-008B to be used with either RI-CTL-MB2B (since you said you wanted to use HyperTerminal, this control module uses RS-232)

http://focus.ti.com/docs/prod/folders/print/ri-stu-251b.html?qgpn=ri-stu-251b

http://focus.ti.com/docs/prod/folders/print/ri-rfm-007b.html?qgpn=ri-rfm-007b + http://focus.ti.com/docs/prod/folders/print/ri-ctl-mb2b.html?qgpn=ri-ctl-mb2b

Housed LF antennas are here ==> http://focus.ti.com/paramsearch/docs/parametricsearch.tsp?family=rfid&sectionId=475&tabId=2104&familyId=1354&paramCriteria=no

LF Tags are here ==>  http://focus.ti.com/paramsearch/docs/parametricsearch.tsp?family=rfid&sectionId=475&tabId=2102&familyId=1352 , just choose 134.2kHz in the parametric selection table and you will see all the devices available.

You could also see this app note i wrote (which was for waste management RFID technology selection, but you can use for your own basic understanding here) http://www.ti.com/lit/an/scba026/scba026.pdf

Josh

Thank you for information

I want to work on HF itself as i have bought 4 TRF7960 from TI. All i want to do is to send continious data from transmitter to reader all the time and reader recognising the righ data. At the moment am using hyperterminal but may use labview to show the output once am sucessfull.

I have replaced TRF7970 chips on two 7960 boards and started working on Peer-Peer communication. Am prefering 7970 as i can use the protocol itself in Mode 2 and send my data ( Was sucessful using TRF7960 with the experiment am working on in DirectMode 0) . I have seen your GUI and couldnt figure out how i can use it in active mode on GUI. Please let me know how and where can i change to make the whole system work in active mode ( C code) .

Cheers

Nanda

Nanda -

i don't want to discourage you here - but again, this is not how the devices are intended to work with each other. So we do not have any canned C code to share with you here other than what is in the firmware now to put the parts into Direct Mode 1 and 0. And the GUI is not set up for this at all, so would recommend that you would be writing your own script here in com emulator/HyperTerminal, Docklight, etc. until you wanted to create a real GUI. In talking to Eddie, who you have the other thread going with, he pointed out you originally wanted 10m of range and were also using an amplifier, too. Truly i think you should have an honest look at the LF approach and also now that i hear about this 10m range, you might also consider using an active radio from us (sub-1GHz like the CC430, CC1101) or higher frequency devices like the RF2500, etc.     

Josh-

In other thread talking to Eddie was about an experiment i was working on where i had big loop of about 10meters on the ground connected to the trf7960 module and at the transmitter side i had another loop which was always transmitting the 10Bites of data. I acheived what i wanted to do in TRF7960 but in DirectMode 0.

As TRF7970 works for Peer-Peer connection(NFC concept), i was expecting to make it work in mode 2 itself with out gettting into Directmode0 as data sent in directmode0 was async data.

For TRF7970 with the GUI available for download in TI website, i want to communicate in active mode which am not able to, can you please give me information on how to connect two units in active mode ??? also can you please share the Host commands for TRF7970 that would help me in understanding the C codes .

Cheers

Nanda