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OM5578: PN7150 not detected on i2c

Question asked by Marcin Pawelec on Jan 11, 2019
Latest reply on Jul 11, 2019 by Jimi Lin




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].



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.



Basing on available circuits:… 


The OM5578 is wired to CP2112-EK as follows:

VANT -> 5V
VEN -> 3.3V
IRQ -> floating


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



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: - 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.