libnfc：无法打开NFC设备

Question

I have a problem with libnfc on a Raspberry Pi 3B trying to read data from a PN532 card reader. I installed libnfc as the official site suggest to do and in fact it all worked this morning. I was able to detect my device using the nfc-list and nfc-scan-device commands.

Then I tried to run a C program (not done by me, but done by a person here in the company) and it worked. Did it again and it didn't work, but returned an error. Tried to run the nfc-list command and it returned the same error. Since then, it looks like the libnfc library stopped working properly.

These are the errors I get when I try to run some commands:

nfc-list :

nfc-list uses libnfc 1.7.1
error   libnfc.bus.i2c  Error: wrote only -1 bytes (10 expected).
error   libnfc.driver.pn532_i2c Unable to transmit data. (TX)
pn53x_check_communication: Input / Output Error
error   libnfc.bus.i2c  Error: wrote only -1 bytes (10 expected).
error   libnfc.driver.pn532_i2c Unable to transmit data. (TX)
nfc-list: ERROR: Unable to open NFC device: pn532_i2c:/dev/i2c-1

nfc-scan-device -v :

nfc-scan-device uses libnfc 1.7.1
1 NFC device(s) found:
error   libnfc.bus.i2c  Error: wrote only -1 bytes (10 expected).
error   libnfc.driver.pn532_i2c Unable to transmit data. (TX)
pn53x_check_communication: Input / Output Error
error   libnfc.bus.i2c  Error: wrote only -1 bytes (10 expected).
error   libnfc.driver.pn532_i2c Unable to transmit data. (TX)
nfc_open failed for pn532_i2c:/dev/i2c-1

LIBNFC_LOG_LEVEL=3 nfc-list :

debug   libnfc.config   key: [device.name], value: [PN532 over I2C]
debug   libnfc.config   key: [device.connstring], value: [pn532_i2c:/dev/i2c-1]
debug   libnfc.config   Unable to open directory: /etc/nfc/devices.d
debug   libnfc.general  log_level is set to 3
debug   libnfc.general  allow_autoscan is set to true
debug   libnfc.general  allow_intrusive_scan is set to false
debug   libnfc.general  1 device(s) defined by user
debug   libnfc.general    #0 name: "PN532 over I2C", connstring: "pn532_i2c:/dev/i2c-1"
nfc-list uses libnfc 1.7.1
debug   libnfc.general  0 device(s) found using acr122_usb driver
debug   libnfc.general  0 device(s) found using pn53x_usb driver
debug   libnfc.chip.pn53x   Diagnose
debug   libnfc.chip.pn53x   Timeout value: 500
debug   libnfc.chip.pn53x   SAMConfiguration
debug   libnfc.chip.pn53x   Timeout value: 1000
debug   libnfc.bus.i2c  TX: 00 00 ff 03 fd d4 14 01 17 00
error   libnfc.bus.i2c  Error: wrote only -1 bytes (10 expected).
error   libnfc.driver.pn532_i2c Unable to transmit data. (TX)
pn53x_check_communication: Input / Output Error
debug   libnfc.chip.pn53x   InRelease
debug   libnfc.bus.i2c  TX: 00 00 ff 03 fd d4 52 00 da 00
error   libnfc.bus.i2c  Error: wrote only -1 bytes (10 expected).
error   libnfc.driver.pn532_i2c Unable to transmit data. (TX)
debug   libnfc.general  Unable to open "pn532_i2c:/dev/i2c-1".
nfc-list: ERROR: Unable to open NFC device: pn532_i2c:/dev/i2c-1

Searched a lot but didn't find anything useful. Thank you.

Answer 1

Have the same problem it was a problem on the circuit I believe. Taking it off and re putting it back solved the problem for me.