nRF52 support ISO7816 protocol

RE: nRF52 support ISO7816 protocol

Tony Garland — Fri, 03 Mar 2017 18:10:09 GMT

Whoops - I just now saw a previous response you made that I hadn't noticed where you say, "if you are using UART of nRF52, there is no such [simultaneous use] issue, since nRF52 take care of UART and BLE." So that answers my question--no need to respond.

RE: nRF52 support ISO7816 protocol

Tony Garland — Fri, 03 Mar 2017 18:06:56 GMT

Hi Jiacheng,

A couple of additional questions if you will permit me?

Are you using the UART for send/receive of the individual ISO-7816 bytes? Or are you bit-banging a GPIO pin (a software UART)?

If you are using the UART, then I'm not certain I understand why 7816 communications would be disturbed by ongoing radio operations by the BLE stack? If the 7816 interface is asynchronous and the UART can buffer data, wouldn't that provide immunity from interference by the radio (similarly to when one uses the UART for debug printing while BLE is active)?

Thanks for your patience - Tony

RE: nRF52 support ISO7816 protocol

Tony Garland — Thu, 02 Mar 2017 02:36:40 GMT

Hi Jiacheng,

I may have misinterpreted your earlier comment:

*I'm not sure if Nordic think it is useful for general purpose and have an official support.*

It sounded like you were saying that the 7816 library you were working on might be "useful for general purpose" and wind up finding "official support" from Nordic for all their customers. Apparently I misunderstood you.

Thanks - Tony

RE: nRF52 support ISO7816 protocol

JiachengWang — Thu, 02 Mar 2017 02:03:03 GMT

(Continue..., there is 1000 Chars limit)

Our ISO7816 library is a proprietary implementation for a new product development, I can not understand what is your mean "to make the library available"? Since the ISO7816 protocol is a part of built-in application program with the final product delivering to customer.

RE: nRF52 support ISO7816 protocol

JiachengWang — Thu, 02 Mar 2017 01:51:38 GMT

It seems we are talking different use case. If you are using UART interface of nRF52 to talk with an IC card, there should have another device is used to connect nRF52 and IC card, one side by UART connection with nRF52, the other side by ISO7816 to talk with IC card. If this is your case, nRF52 only take are the UART package, no relationship with ISO7816.

What I've said is that nRF52 is working as full functional card reader, the IC card contactors have directly electrical connection with nRF52 GPIO.

Yes, ISO7816 has no relationship with BLE. In our case, the application program take care the time events form BLE and ISO7816. For example, since Softdevice use the highest interrupt of nRF52, so the ISO7816 packets may be corrupted by BLE events, a sanity check is used for each ISO7816 packet. But if you are using UART of nRF52, there is no such issue, since nRF52 take care UART and BLE.

RE: nRF52 support ISO7816 protocol

Tony Garland — Thu, 02 Mar 2017 00:57:59 GMT

Hi Jiacheng,

Thanks for the additional information.

In our case, we are talking to a custom part and the UART interface to the card/part does not require the high current supply--so that part isn't an issue for us. But we do need to talk using 7816 protocol. I'm not certain yet whether we would try to interleave it with BLE using time slots, or whether we may be able to make the two mutually exclusive (e.g., disable the radio for the situations where we need to use 7816 protocol).

From what you've said, it sounds like the 7816 library you are using does not have built-in support for arbitrating with the radio using time slots--that the application level has to take care of managing the time slots and be sure to only use the 7816 library at the allowable times? Or does the library provide time slot management too?

Finally, is there any plan to make the library available?

RE: nRF52 support ISO7816 protocol

JiachengWang — Thu, 02 Mar 2017 00:27:59 GMT

It is a total custom implementation, I'm not sure if Nordic think it is useful for general purpose and have an official support.

I think it is no problem for nRF51/52 work as a card to interact with interface device (card reader). However, if use nRF51/52 as a general card reader, there are some electrical specification issues, for example, ISO/IEC 7816 requires the current supply is up to 50mA, this can not be provided by GPIO of nRF51/52. Although with our implementation, nRF51/52 are working perfectly as a SIM/USIM card reader, but I have no idea if use nRF 51/52 as a general card reader.

About our progress, it is no problem to let the 2 stacks (Softdevide and ISO7816) work "together" as TDM manner, it is working in our implementation. Since at any time, there is only 1 stack running. We are trying to make 2 stacks work concurrently by using timeslot feature of Softdevice.

RE: nRF52 support ISO7816 protocol

Tony Garland — Wed, 01 Mar 2017 17:35:33 GMT

Hello Jiacheng,

You mentioned "currently we are working on 2 protocol stack (BLE and ISO7816) work together with TDM." Is this something that Nordic is making available for general use? Is it available yet--or is there a timeline where you can say it might become available?

Thanks - Tony

RE: nRF52 support ISO7816 protocol

JiachengWang — Fri, 07 Oct 2016 13:34:35 GMT

One point, with our implementation, the ISO7816 stack can not be run as an application program of SoftDevice, i.e., ISO7816 stack and BLE stack can not be run at the same time, since ISO7816 packet TX/RX can not be interrupted. Currently we are working on 2 protocol stack (BLE and ISO7816) work together with TDM (time division multiplexing) manner.

RE: nRF52 support ISO7816 protocol

Gopal — Fri, 07 Oct 2016 09:04:16 GMT

Thank you Jiacheng... we will implement this.. if any issues we will get back to you..

RE: nRF52 support ISO7816 protocol

JiachengWang — Fri, 07 Oct 2016 08:46:54 GMT

For clock signal generation, "devzone.nordicsemi.com/.../ give an example to let GPIO has 4M clock signal output.

For GPIO work as IO pin of ISO/IEC7816, "devzone.nordicsemi.com/.../" give the example code.

To implement the ISO/IEC7816 protocol stack, just according the Spec document of ISO/IEC7816 to interact with the smart card or card reader (depends on nRF52/51 act as card reader or start card).

RE: nRF52 support ISO7816 protocol

Gopal — Fri, 07 Oct 2016 05:58:33 GMT

Hi,

Do you have any reference design with ISO7816 protocol/interface?

if so, can you kindly share the design?

RE: nRF52 support ISO7816 protocol

JiachengWang — Fri, 07 Oct 2016 03:29:36 GMT

You can use nRF52/51 as a general MCU to implement ISO/IEC 7816 protocol, the GPIOs of nRF52/51 are the smart card interface VCC/CLK/RST/IO, etc. nRF52/51 can work as card device or interface device (card reader). In our wireless SIM implementation, nRF52/51 is used to run SIM/USIM protocol.