P71D600 or P71D321

[fcovely]

I'm a newbie to hardware in general and have a question that is probably common knowledge but I have been unable to find an answer, so apologies if this is a super basic question.

My team put a P71D600 on a PCB that always has power going to the P71.  The chip cannot be seen by RFID readers unless we power down the entire product then it works fine.

Is there a lock mechanism between contactless and contact operations on these chips?  Is there anway to still do contactless transactions while supplying power to the P71?

[Kan_Li]

Hi @fcovely ,

The interface in use is chosen at boot so if the device is powered via power pins either the I2C or the contact interface will be chosen according to configuration. Note it is not possible to have two interfaces operating simultaneously.

If the device is powered up in a field but no power is applied to the pins directly, then the contactless interface is enabled.

We have raised as a requirement on R & D to update the documentation, as it is not clearly stated.

Have a great day,
Kan

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[msjcard · Accepted solution]

The short answer is no.

I think it's in one of the long data sheets for the JCOP 4 or 4.5 product - but there's a specific flow chart that describes which connection becomes active at which point in time.  Generally, the physical connections tend to have priority over the NFC connection.   Once you power on the chip via that connection, you can use multiple logical channels to the chip over that connection, but the chip will not see or be seen on the RF side of things.

The only real way to get a dual connection might be to have a second chip NFC reader and use the JCOP4/4.5s ability to act as an I2C master to talk to that chip.

[fcovely]

Thank you, that's all I was looking for I'll try and run down the actual document.

[msjcard]

It's in the UM615217 User Guidance and Admin for JCOP4.5 P71.  Section 3.2:

Communication can only be initiated on a
single interface at any one time. Interface selection is performed at card power on, therefore the active communication
interface can only be changed by resetting the card. If more than one physical interface is detected then
the priority order for selection is contact, then contactless, then I2C or SPI depending on the platform base mask.

[msjcard]

On a quick search I can't find the document specific to the P71 series, but take a look at DS206631 - Product data sheet for the A700x series.  Section 10.5.  

I know I've seen a similar section for either the D321 or D600 - but I couldn't tell you where right now.