xblink/tools/provision_eh.py

#!/usr/bin/env python3
"""
Configure NTAG5Link energy harvesting for 1.8V automatic VOUT.

Writes EH_CONFIG to persistent EEPROM (block 0x3D) so the NTAG5
automatically outputs 1.8V when an NFC field is present — powering
the SAMD21 MCU without any firmware intervention.

Also sets ED_CONFIG (FD pin) for NFC-to-I2C SRAM pass-through so
the MCU can detect SRAM writes from the phone.

Usage:
    # Read current EH config:
    python provision_eh.py --read

    # Write 1.8V / 6.5mA EH config:
    python provision_eh.py --write

    # Write with custom current limit:
    python provision_eh.py --write --current 4.0

    # Also configure CONFIG_0 and CONFIG_1 for xblink:
    python provision_eh.py --write --full
"""

import argparse
import sys
import os

# Add ntag5sensor to path
ntag5sensor_path = os.path.join(os.path.dirname(__file__), "..", "..", "ntag5sensor")
sys.path.insert(0, ntag5sensor_path)

from reader.acr1552 import ACR1552
from vicinity.iso15693 import ISO15693
from vicinity.ntag5link import (
    Ntag5Link,
    NXP_EH_CONFIG_EH_VOUT_V_SEL_1_8,
    NXP_EH_CONFIG_EH_VOUT_V_SEL_2_4,
    NXP_EH_CONFIG_EH_VOUT_V_SEL_3_0,
    NXP_EH_CONFIG_EH_VOUT_I_SEL_0_4,
    NXP_EH_CONFIG_EH_VOUT_I_SEL_0_6,
    NXP_EH_CONFIG_EH_VOUT_I_SEL_1_4,
    NXP_EH_CONFIG_EH_VOUT_I_SEL_2_7,
    NXP_EH_CONFIG_EH_VOUT_I_SEL_4_0,
    NXP_EH_CONFIG_EH_VOUT_I_SEL_6_5,
    NXP_EH_CONFIG_EH_VOUT_I_SEL_9_0,
    NXP_EH_CONFIG_EH_VOUT_I_SEL_12_5,
    NXP_ED_CONFIG_NFC_TO_I2C_PASS_THROUGH,
    NXP_CONFIG_0_EH_MODE_LOW_FIELD_STRENGTH,
    NXP_CONFIG_1_ARBITER_MODE_SRAM_PASSTHROUGH,
    NXP_CONFIG_1_USE_CASE_CONF_I2C_SLAVE,
)

# Current limit lookup: string -> constant
CURRENT_MAP = {
    "0.4": NXP_EH_CONFIG_EH_VOUT_I_SEL_0_4,
    "0.6": NXP_EH_CONFIG_EH_VOUT_I_SEL_0_6,
    "1.4": NXP_EH_CONFIG_EH_VOUT_I_SEL_1_4,
    "2.7": NXP_EH_CONFIG_EH_VOUT_I_SEL_2_7,
    "4.0": NXP_EH_CONFIG_EH_VOUT_I_SEL_4_0,
    "6.5": NXP_EH_CONFIG_EH_VOUT_I_SEL_6_5,
    "9.0": NXP_EH_CONFIG_EH_VOUT_I_SEL_9_0,
    "12.5": NXP_EH_CONFIG_EH_VOUT_I_SEL_12_5,
}


def read_config(chip):
    """Read and display current EH and general config."""
    print("=== NTAG5 Configuration ===\n")

    info = chip.get_system_info()
    print(f"UID: {info['uid'].hex()}")

    config = chip.get_config_info()
    print(f"\nCONFIG_0:")
    print(f"  EH mode: {config.get('energy_harvesting_mode', '?')}")
    print(f"  SRAM copy: {config.get('sram_copy_enabled', '?')}")
    print(f"  Auto standby: {config.get('auto_standby_mode', '?')}")

    print(f"\nCONFIG_1:")
    print(f"  SRAM enable: {config.get('sram_enabled', '?')}")
    print(f"  Arbiter mode: {config.get('arbiter_mode', '?')}")
    print(f"  Use case: {config.get('use_case', '?')}")
    print(f"  EH arbiter: {config.get('eh_arbiter_mode_enabled', '?')}")

    eh = chip.get_eh_ed_config_info()
    print(f"\nEH_CONFIG (block 0x3D):")
    print(f"  EH enable: {eh.get('eh_enable', '?')}")
    print(f"  VOUT voltage: {eh.get('eh_vout_v_sel', '?')}V")
    print(f"  VOUT current: {eh.get('eh_vout_i_sel', '?')}mA")
    print(f"  Power check disabled: {eh.get('disable_power_check', '?')}")
    print(f"  ED/FD config: {eh.get('ed_config', '?')}")


def write_eh(chip, current_sel, full_config=False):
    """Write EH config for 1.8V automatic come-up."""

    print("Writing EH config: 1.8V, current limit = "
          f"{[k for k,v in CURRENT_MAP.items() if v == current_sel][0]}mA")
    print(f"  ED/FD pin: NFC-to-I2C pass-through (SRAM write detect)")

    chip.write_eh_ed_config(
        enable=True,
        disable_power_check=False,
        current=current_sel,
        voltage=NXP_EH_CONFIG_EH_VOUT_V_SEL_1_8,
        ed_config=NXP_ED_CONFIG_NFC_TO_I2C_PASS_THROUGH,
    )
    print("  EH_CONFIG written.")

    if full_config:
        print("\nWriting CONFIG_0: EH mode = low field strength")
        chip.write_config0(
            eh_mode=NXP_CONFIG_0_EH_MODE_LOW_FIELD_STRENGTH,
        )
        print("  CONFIG_0 written.")

        print("Writing CONFIG_1: SRAM enable, arbiter=passthrough, use_case=I2C slave")
        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,
        )
        print("  CONFIG_1 written.")

    # Verify
    print("\n--- Verify ---")
    read_config(chip)


def main():
    parser = argparse.ArgumentParser(
        description="Configure NTAG5Link energy harvesting for 1.8V")
    parser.add_argument("--read", action="store_true",
                        help="Read current config (no writes)")
    parser.add_argument("--write", action="store_true",
                        help="Write EH config for 1.8V automatic VOUT")
    parser.add_argument("--current", default="6.5",
                        choices=list(CURRENT_MAP.keys()),
                        help="VOUT current limit in mA (default: 6.5)")
    parser.add_argument("--full", action="store_true",
                        help="Also write CONFIG_0 and CONFIG_1 for xblink")
    args = parser.parse_args()

    if not args.read and not args.write:
        parser.print_help()
        sys.exit(1)

    reader = ACR1552()
    reader.connect()
    iso = ISO15693(reader)
    chip = Ntag5Link(iso)

    if args.read:
        read_config(chip)

    if args.write:
        current_sel = CURRENT_MAP[args.current]
        write_eh(chip, current_sel, full_config=args.full)

    reader.disconnect()


if __name__ == "__main__":
    main()