The actual datasheet for TRF7970 is full of errors ( SLOS743 - AUGUST 2011). It seems to be a copy of the datasheet for TRF7960, slightly modified with the new features / functions of the TRF7970. In particular the length of the FIFO is mixed several times between 12 bytes and 128 bytes. The description of Register 0x1C (FIFO status) on page 74 must be wrong because it says that there are just 4 bits as FIFO counter.
Is there any clarification on the FIFO matter available. Is there an updated datasheet available ?
Btw the position of C7 in the application schematics on pages 13 and 14 is wrong (...what is a little bit embarrasing)
Thank you...
i've noticed it too, and i've already asked for some explanations about the FIFO status register here -> http://e2e.ti.com/support/low_power_rf/f/667/t/168173.aspx but I still didn't get any answer.
0268.TRF7970A_SPI_MSP430F23x0_schematic.pdf
7558.TRF7970A_Parallel_MSP430F23x0_schematic.pdf
Updated schematics attached - DS update is on the way - no kidding this time. :) Should be updated on the web this week.
Sorry it has taken this long - BTW - in the DS - there are multiple links (like on almost every page) to submit document feedback - this is the correct mechanism for when you find errors in our docs.
RE: the FIFO status register - i thought i had answered this before.
The answer is that B7 of this register is the overflow indicator and B6: B0 now indicate # of bytes in the register to read (value is n, not n-1, like what is seen in the TRF796x devices.)
BR-
Josh
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Thank you Josh,
looking forward to the updated DS.
I never really noticed the "Submit Document Feedback" on the bottom of each page as a way to submit errors. I will use it in the future.
Regards
Rolf
as promised - the updated version of the DS is up on the web now in the TRF7970A product folder.
http://www.ti.com/lit/ds/symlink/trf7970a.pdf
the new one is much better !
Although your link still points to the old datasheet.
I got the updated one under the following link from the TFR7970A folder:
http://www.ti.com/lit/ds/slos743a/slos743a.pdf
There are still some minor errors.
This time i used the 'Submit Document Feedback' at the bottom of each page of the new DS to tell you, what I did notice.
The new DS still says, that B3 of register 0x00 has to be "1" to select the Main RX input. That isn't right, is it ?
Josh Wyatt no kidding this time. :)
Are you sure?
The default value for register 0x01 is not 0x02 (ISO15693 high bit rate, one subcarrier, 1 out of 4) but 0x21 NFC Mode 106 kbps.
In another thread I written the copy and paste for bit 5/6 in register 0x1A.
I'm a newbie and I never found error in datasheets, for this datasheet is too easy find errors.
john -
this time its your mistake. The default for register 0x01 is 0x02.
After command 0x03 (0x83 with SPI)
read register 0x01(0x41 with SPI) return 0x21.
I test many times before write it, and now I retest another one, always 0x21.
My TRF7970A is not a clone chinese, I hope.
In my board EN2 is attached to GND and EN became VCC, one second after power up.
Can you explain me?
Thank you
John.
John -
the sequence for the TRF7970A should be: bring up the EN line, 0x83 (soft init), write the 0x09 register with B7=0 (if using 13.56MHz crystal), then you can read the registers - please try this out for me.
This is my sequence:
All other registers is read correctly, only register 0x01 hasn't default value. My TRF7970A is sample from TI, can't be a clone chinese. My TRF7970A works very well with my tests ISO14443A/B and ISO15963. It's not broken.
I hope someone do the same test and report it.
John