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OM5578: PN7150 not detected on i2c

Question asked by Marcin Pawelec on Jan 11, 2019
Latest reply on Jan 15, 2019 by Marcin Pawelec

Hi,

 

[Background]

Continuing my last time research on new NFC ICs I've obtained a OM5578 board [Arduino pinout] and PN7150 USB Dongle from Mikroelektronika. The Dongle itself was communicating with an USB through LPC11U24 uC. As a ready product it worked well. Then came a time to dismount a uC and to try merging a PN7150 with a HID USB to SMBus/I2C bridge: CP2112-EK from Silicon Labs. The task was to interface a PN7150 with an i2c master circuit that way it would not require additional uC programming [only an app running on linux].

 

[Problem]

A problem I've encountered is an inability to detect a PN7150 via I2C. Neither dismounted Dongle nor OM5578 can be seen when i2cdetect runs. I2C bridge actually works correctly - e.g. AT24C01A EEPROM is being detected correctly.

 

[Hardware]

Basing on available circuits:

https://download.mikroe.com/documents/add-on-boards/other/wireless-connectivity/nfc-usb-dongle/nfc-usb-dongle-schematic-… 

https://www.silabs.com/documents/public/user-guides/CP2112-EK.pdf 

https://www.nxp.com/docs/en/user-guide/UM10935.pdf 

 

The OM5578 is wired to CP2112-EK as follows:

VBAT+PVDD -> 3.3V
VANT -> 5V
VEN -> 3.3V
SCL -> SCL
SDA -> SDA
GND -> GND
IRQ -> floating

 

The actual measurement of 3.3 line shows up to 3.6 but it remains within the working range.

 

[Questions]

1.) Am I missing some connection here?

2.) Is there a chance I've fried both PNs?

3.) Is there perhaps a peculiar timing required to turn the VEN on or an ON/OFF sequence?

4.) Prowling on the Farnell I've encountered a PN7150 with 1.65V to 1.95V supply: https://www.newark.com/nxp/pn7150b0hn-c11002y/frequency-min/dp/06AC2460?st=pn7150 - it is not an actual supply but it applies to VDD and it is just an output which should be connected to VDDA and VDDD, am I right?

5.) I'm expecting a 0x28 address to be found.

 

Regards,

Marty

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