Files

michael 90eab7990c Rewrite config check for PCSC, document uFR Zero CCID limitations

The uFR Zero presents as CCID (not serial), so the uFCoder library
cannot communicate with it. Rewrote ntag5_config_check.py to use
pyscard with auto-detection: ACR1552 for full NXP config verification,
generic PCSC for basic tag info. Removed uFCoder library (unusable).

Backed up CCID Info.plist before adding uFR Zero VID:PID entry.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

2026-03-03 15:27:04 -08:00

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NTAG5Link Config Verification via NFC Reader

Date: 2026-03-03 Status: Partial — tag detected, config read requires ACR1552

Goal

Read-only verification that the NTAG5Link Click board's configuration matches xblink requirements.

Tool

tools/ntag5_config_check.py — Python script using pyscard (PCSC) with auto-detection of reader capabilities.

Reader support:

ACR1552: Full NXP config verification via transparent ISO15693 mode (NXP READ_CONFIG 0xC0)
uFR Zero (CCID): Basic tag info only — UID, EEPROM blocks. Cannot read NXP config registers.

Expected Config

Setting	Expected	Config Location
EH mode	low_field_strength	CONFIG byte 0, bits 3:2 = 10
Use case	i2c_slave	CONFIG byte 1, bits 5:4 = 00
SRAM enabled	true	CONFIG byte 1, bit 1 = 1
Arbiter mode	sram_passthrough	CONFIG byte 1, bits 3:2 = 10
EH enable	true	EH_CONFIG byte 0, bit 0 = 1
EH voltage	3.0V	EH_CONFIG byte 0, bits 2:1 = 10

uFR Zero Investigation Results

The D-Logic uFR Zero Multi-ISO reader presents as a CCID (USB SmartCard class 0x0B) device, not serial.

USB: VID:PID 3629:301b, serial "UD101156"

What works (PCSC/CCID)

Command	APDU	Result
GET_DATA (UID)	`FF CA 00 00 00`	UID: `E0:04:01:58:7F:8F:11:00` (NXP ISO15693)
READ_BINARY	`FF B0 00 xx 00`	Reads ISO15693 user EEPROM blocks
NDEF CC (block 0)	`FF B0 00 00 00`	`E1 40 80 09` — NDEF v4.0, 1024 bytes

What doesn't work

Approach	Result	Why
uFCoder `ReaderOpen`	0x1002 (timeout)	Library scans serial/tty, doesn't support CCID USB
uFCoder `ReaderOpenHnd_ZeroUSB`	0x0054 (opening error)	Even with pcscd stopped
PCSC transparent (FF C2)	SW=6A81	Not supported by uFR Zero CCID firmware
CCID escape (IOCTL 0x42000001)	6A81 for all commands	Advertised but non-functional
Raw ISO15693 via SCardControl	6A81	No passthrough mechanism

Key finding: CP210x is NOT the uFR Zero

/dev/ttyUSB0 (10c4:ea60, Silicon Labs CP210x) is a separate device (Proxmark3). The uFR Zero is a pure CCID device with no serial interface.

CCID setup required

The uFR Zero must be added to the CCID driver's device list:

Add VID 0x3629 / PID 0x301B to /usr/lib/pcsc/drivers/ifd-ccid.bundle/Contents/Info.plist
Set ifdDriverOptions to 0x0001 (enables CCID exchange — though escape commands still return 6A81)
Restart pcscd: systemctl restart pcscd

Path Forward: ACR1552

The ACR1552 reader supports transparent ISO15693 mode (FF C2 pseudo-APDUs with TLV encoding), enabling NXP custom commands. The ntag5_config_check.py tool auto-detects the ACR1552 and switches to full config verification mode.

# ntag5sensor has proven ACR1552 + NXP custom command support:
chip = NTAG5Link(reader)
config = chip.get_config_info()
eh_config = chip.get_eh_ed_config_info()

Config Change Plan (if mismatches found)

Use ntag5sensor's write functions via ACR1552:

# Set I2C slave mode + SRAM passthrough + SRAM enable
chip.write_config1(
    sram_enable=True,
    arbiter_mode=NXP_CONFIG_1_ARBITER_MODE_SRAM_PASSTHROUGH,
    use_case=NXP_CONFIG_1_USE_CASE_CONF_I2C_SLAVE
)

# Set EH: 3.0V, enabled, current limit TBD
chip.write_eh_ed_config(
    enable=True,
    voltage=NXP_EH_CONFIG_EH_VOUT_V_SEL_3_0,
    current=NXP_EH_CONFIG_EH_VOUT_I_SEL_12_5,  # max for testing
    ed_config=NXP_ED_CONFIG_NFC_FIELD_DETECT
)

# Set EH mode in CONFIG byte 0
chip.write_config0(eh_mode=NXP_CONFIG_0_EH_MODE_LOW_FIELD_STRENGTH)

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