pnev7642fama_pn76_hostif_spi

[asknxp]

Hi there,

We tried to develop a communication channel between PN7642 and our Linux host through SPI bus.

Here is what we tried on the PN7642 devKit((https://www.nxp.com/products/rfid-nfc/nfc-hf/nfc-readers/development-kit-for-pn7642-secure-compact-n...))

• PN7642 devkit Connect SPI bus to RPI4 linux host's SPI master node.
  • J36 PIN 8 : GND     <--> PIN 25
  • J36 PIN 10: SCLK  <--> PIN 23
  • J36 PIN 12: MISO.  <-->PIN 21
  • J36 PIN 14: MOSI.  <-->PIN 19
  • J36 PIN 16: CS       <-->PIN 24
• Loading pnev7642fama_pn76_hostif_spi fw onto PN7642
• Set HOSTSEL SW 0-2 to SPI interface. This should be the default value
• Send lookBack TLV command from linux host to PN7642 devKit
• We also verified our program and make sure it can send proper lookback TLV command with Ardunio board to make sure nothing wrong on our linux host end

Here is the command we sent.

7F 00 00 20 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F

It seems the PN7642 did not receive the command. Any insight? Do we need to do anything besides SPI wiring?

Thank you very much.

--Kenny

[EduardoZamora]

Hello,

Could you please provide a log/output from your application? Also, it would be very helpful if you could share a capture of the SPI lines by using a logic analyzer or an oscilloscope.

What is the position of SW5, SW6, SW7 in your setup?

You can find more information about this demo, requirements, settings and preparation inside the project > docs > readme.txt.

Regards,
Eduardo.

[asknxp]

Thanks Eduardo.

I got the LPCXpresso55S16 board and followed readme.txt to compiled the firmware on PNEV7642FAMA and run HifEx_Counterpart project on LPCXpresso55S16. The SPI communication works as expected.

For hostSel switches,

SW5:0

SW7:0

SW6:1

We have no problem to run HifEx_Counterpart example. In that case, hardware PNEV7642FAMA settings should be all good. Quickly skimmed HifEx_Counterpart source code. It seems that host end needs to trigger a couple of gpio pins. 

J37 PIN3: DWL_REQ
J37 PIN5: hostSel0
J38 PIN8 : hostSel2
J38 PIN10: hostSel1
J38 PIN12: VEN_RST

I am going to modify my test program to trigger those gpio pins to simulate the behavior and see how it goes.

Ideally, do you have any linux example to work with pnev7642fama_pn76_hostif_spi?

Other than that, I have another question for you.

PN7642 does not support NCI method so we need to have a way for PN7642 to send MIFAREDESFire credential data to our linux host. We have another project by using PN7150 and it is pretty easy to implement a linux application by using linux_libnfc-nci library.

Do you think it is a good idea by using something like pnev7642fama_pn76_hostif_spi as an example to provide the communication channel between PN7642 and host? If not, do you have any suggestions. Majorly we just need to have a way for PN7642 to send credential data to linux host when people present a credential

Thank you very much.

--Kenny

[EduardoZamora]

Hi,

Unfortunately, there is no Linux example that could meet your requirements.

Since PN7642 is a Programmable NFC Controller combining an NFC frontend with an Arm® Cortex®-M33-based MCU, it is intended to be a solution that replaces the need for an extra MCU. As you mention, some devices such as PN7160 or PN5190 are a good choice when working with a host OS like Linux.

I truly apologize for the inconvenience this might cause you.

Regards,
Eduardo.

[asknxp]

Got it. Thanks Eduardo.

--Kenny