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232204 - EverTag Connectivity Module Base PCB Full
Article Number 232204
Name EverTag Connectivity Module Base PCB Bat + WIFI + PIR + LTE Ext
Base PCB 232200 Base Std
Added Features Battery + WiFi + PIR/Radar sensor + LTE extension connector
Status Not included in the first PCB iteration

Not in First PCB Iteration

This PCB variant is fully specified but is not included in the first PCB production run. The base platform (232200) and enclosure (232506) are designed to accommodate this variant in a future iteration. The specification is provided here so that the PCB designer can ensure forward-compatibility in the base platform design.

1. Overview

The 232204 is the full-featured base PCB variant, extending the 232203 (battery + WiFi) with a PIR/Radar occupancy sensor and a board-to-board connector for the LTE extension PCB (232210/232211). It is the most populated and complex variant in the EverTag Connectivity Module family.

Key Features

  • Everything in 232203 Base Bat+WIFI: PAN611, ST25DV04K NFC, dual SK6812 LED (both populated), USB-C, service button, battery, WiFi
  • PIR or Radar occupancy/presence sensor
  • Board-to-board connector footprint (Harwin M20, 2.54mm, SMT) for LTE extension PCB (232210/232211)
  • Power rail designed for 2A burst (required for LTE modem TX via B2B connector)

SIM, Antenna, and Level Shifters on Extension Board

The SIM card holder, on-board chip antenna (Quectel YC0001CA), 3.8V LDO, and 1.8V↔3.3V level shifters are all on the extension PCB (232210/232211), not on this base PCB. SIM signals stay local to the modem on the extension board. The chip antenna is SMD-mounted directly on the extension PCB (no cable). Level shifting between the modem's 1.8V logic and the ESP32's 3.3V logic happens on the extension board. All B2B signals are at 3.3V -- this base PCB needs no LTE-specific voltage translation.

2. Block Diagram

graph TB
    subgraph power [Power Supply - Full Platform]
        VIN["5V Input from Power Base"] --> PPM["Power-Path Manager"]
        BAT["LiFePO4 Battery"] --> VPROT["Voltage Protection"]
        VPROT --> PPM
        PPM --> BUCK["TPS62160 Buck Converter"]
        BUCK --> RAIL["3.3V Rail"]
        RAIL --> LDO_WIFI["WiFi LDO"]
        LDO_WIFI --> WIFI_PWR["3.3V WiFi Rail"]

        PPM --> CHRG["MCP73123 Charger"]
        CHRG --> VPROT

        VIN --> LTE_PWR["LTE Power Rail - 2A burst"]
    end

    subgraph mcu_block [MCU / Radio Module]
        PAN611["PAN611 - nRF54L15"]
    end

    subgraph wifi_block [WiFi Gateway]
        ESP32["ESP32-C5 WROOM"]
    end

    subgraph sensor [Occupancy Sensor]
        PIR["PIR / Radar Sensor"]
    end

    subgraph lte_base [LTE Extension Interface - on 232204 base]
        B2B_BASE["B2B Header: Harwin M20"]
    end

    subgraph lte_ext [232210/232211 Extension PCB - stacked on top]
        B2B_EXT["B2B Socket: Harwin M20"]
        MODEM["SIMCom SIM7672E/NA<br/>(1.8V I/O)"]
        LVLSHIFT["Level Shifters<br/>(1.8V↔3.3V)"]
        LDO38["3.8V LDO"]
        SIM["SIM Card Holder"]
        CHIP_ANT["Chip Antenna<br/>(YC0001CA)"]
    end

    subgraph nfc_block [NFC]
        ST25DV["ST25DV04K"]
        NFCANT["2-Layer Coil Antenna"]
    end

    subgraph indicators [UI]
        LED1["SK6812 #1 System LED"]
        LED2["SK6812 #2 Telematics LED"]
    end

    RAIL --> PAN611
    WIFI_PWR --> ESP32
    RAIL --> PIR
    LTE_PWR --> B2B_BASE

    PAN611 <-->|"UART1: Dual-MCU API"| ESP32
    ESP32 -->|"COEX REQUEST"| PAN611
    PAN611 -->|"COEX GRANT"| ESP32
    ESP32 -->|"READY"| PAN611
    PAN611 <-->|"I2C/GPIO"| PIR
    ESP32 <-->|"LTE UART + control"| B2B_BASE
    B2B_BASE <-->|"14-pin B2B"| B2B_EXT
    B2B_EXT -->|"5V"| LDO38
    LDO38 -->|"3.8V"| MODEM
    B2B_EXT <-->|"3.3V"| LVLSHIFT
    LVLSHIFT <-->|"1.8V"| MODEM
    MODEM <--> SIM
    MODEM --> CHIP_ANT
    PAN611 -->|"I2C"| ST25DV
    ST25DV --> NFCANT
    PAN611 -->|"P0.01 data"| LED1
    LED1 -->|"daisy-chain"| LED2

    PAN611 -.->|"Battery mgmt"| PPM

3. Schematics

3.1 Occupancy Sensor Interface (Multi-Option)

The sensor type is a customer-driven BOM decision. The PCB routes a 5-pin sensor interface to a footprint area near the enclosure front, supporting three sensor families via the same pin set:

Parameter Value
Interface Options SPI (radar), UART (radar), Analog + digital (PIR), I2C (shared)
Supply 3.3V
Detection Occupancy / presence (motion and/or static)
nRF54 Pins P1.11, P1.13, P1.14 (SAADC-capable), P1.08, P2.09

Sensor Interface Pin Assignment

Pin SAADC Direction SPI Use (Radar) UART Use (Radar) Analog Use (PIR) Notes
P1.11 AIN4 Output SPI_CLK UART_TX (to sensor) -- Freed from UART1 TX
P1.13 AIN6 Input SPI_MISO UART_RX (from sensor) Analog in (PIR signal) Freed from UART1 RX
P1.14 AIN7 Output SPI_MOSI -- -- Freed from ESP32_RESET
P1.08 -- Output SPI_CS -- -- Freed from SPI CS
P2.09 -- Input IRQ / data ready Presence out Digital out (comparator) Freed from ACC INT2

Additionally, the I2C bus (P1.04/P1.05) is available as a shared bus with ST25DV04K for I2C-based sensors.

Option A: SPI Radar (e.g., Acconeer A121)

Pulsed coherent radar (60 GHz). Excellent static presence detection. SPI interface uses all 4 dedicated pins + IRQ.

Feature Value
Interface SPI (CLK, MISO, MOSI, CS) + IRQ
Detection Motion + static presence, 0--10m
Power ~30--80 mA active, duty-cyclable
RF coexistence 60 GHz -- zero concern with 2.4 GHz
Enclosure No IR window needed (radar penetrates plastic)
Dev effort Medium (SPI driver + algorithm tuning)
BOM ~$5--8 (module)

Integrated 24 GHz radar module with built-in signal processing. UART AT command interface.

Feature Value
Interface UART (TX, RX) + digital presence out
Detection Motion + presence, 0--5m
Power ~50--80 mA active
RF coexistence 24 GHz -- zero concern with 2.4 GHz
Enclosure No IR window needed
Dev effort Low (UART AT commands, digital threshold)
BOM ~$3--5 (complete module, larger footprint ~20x15mm)

Option C: Analog PIR (e.g., Murata IRA-S210ST01, Winsen RD-624)

Bare dual-element pyroelectric sensor in TO-5 package. Requires an external analog frontend (amplifier + bandpass filter + comparator) on the PCB.

Feature Value
Sensor interface Analog output → AIN6 (P1.13) via frontend
Frontend output Digital comparator → P2.09
Detection Motion only (not static presence), 5--10m
Power ~1--10 uA (sensor), ~50--100 uA (frontend)
Enclosure IR-transparent window required (Fresnel lens)
Dev effort Low (ADC threshold + digital interrupt)
BOM ~$2--3 (element + frontend ASIC + lens)

PIR analog signal path:

graph LR
    PIR["PIR Element<br>(IRA-S210ST01<br>or RD-624)"] -->|"µV signal"| AMP["Frontend ASIC<br>(e.g. Renesas EFM310)"]
    AMP -->|"Amplified analog"| AIN["P1.13 / AIN6<br>(nRF54 SAADC)"]
    AMP -->|"Comparator out"| DIG["P2.09<br>(digital IRQ)"]

The analog mid-point on AIN6 enables firmware-adjustable detection thresholds via SAADC, while the hardware comparator on P2.09 provides low-latency interrupt wakeup without requiring the ADC to be continuously running.

Candidate PIR elements:

Manufacturer Part Number Package Supply Est. Price Notes
Murata IRA-S210ST01 TO-5 2--15V ~€1.10 Industry standard, Murata IML lens compatible
Winsen RD-624 TO-5 3--15V ~$0.80 Drop-in alternative, budget-friendly

Candidate Fresnel lenses: Murata IML-0686/IML-0687, FresnelFactory PD05-12005, Senba SB-F-02.

Frontend ASIC candidate: Renesas EFM310 (SOP-8, integrates amp + filter + comparator, single-chip PIR frontend).

Option D: I2C Sensor (Future)

Any I2C occupancy sensor can share the existing bus (P1.04 SCL, P1.05 SDA) with ST25DV04K. P2.09 serves as alert/IRQ pin. No additional pin routing needed.

Sensor Comparison Summary

Criterion A: SPI Radar (A121) B: UART Radar (LD2410) C: Analog PIR D: I2C Sensor
Static presence detect Excellent Moderate No Depends
10m range Yes Borderline Yes Depends
IR window needed No No Yes Depends
Assembly complexity 1 module 1 module (large) TO-5 + ASIC + lens 1 module
BOM cost $$ $ $ Varies
Dev effort Medium Low Low Depends
Power 30--80 mA 50--80 mA <0.1 mA Varies

Customer-Driven Selection

The sensor type is not finalized -- it depends on end-customer requirements (capability vs. cost vs. dev effort). The PCB is designed to accommodate all options via the same 5-pin interface. The BOM and sensor sub-assembly determine which option is populated. Assembly is optimized for European SMT: radar options are single-module reflow; PIR option is TO-5 element + SOP-8 ASIC + through-hole or clip-on Fresnel lens.

Design notes:

  • Sensor footprint area must face the enclosure front -- the enclosure (232506) has a prepared sensor window region
  • Keep sensor away from heat-generating components (buck converter, ESP32 during TX)
  • For PIR option: consider IR-transparent window material in enclosure cover
  • For radar options: no special enclosure window needed (24/60 GHz penetrates plastic)

3.2 LTE Extension Board-to-Board Connector

Parameter Value
Connector Family Harwin M20 series, 2.54mm (0.1") pitch
Base PCB (header) Harwin M20-8750742 (2x7, 14-pin, vertical SMT)
Stacking Height ~10--11mm PCB-to-PCB (5.8mm pin + 3.75mm socket)
Pin Count 14 (11 assigned + 3 spare)
Current Rating 3A per contact
Power 5V / 2A burst capable (doubled GND pins for current return)

The B2B connector carries power and ESP32 control signals only -- no SIM or RF signals. SIM and RF coax are local to the extension board.

B2B Pin Assignment

Pin Signal Direction (base→ext) Notes
1 VIN_5V Power → ext 2A burst for LTE modem TX
2 GND Power Current return #1
3 GND Power Current return #2 (doubled for 2A)
4 LTE_UART_TX ESP32 → modem AT commands to LTE modem
5 LTE_UART_RX modem → ESP32 AT responses from LTE modem
6 LTE_POWER_KEY ESP32 → modem Modem power on/off
7 LTE_RESET ESP32 → modem Hardware reset (recovery from hung modem)
8 LTE_STATUS modem → ESP32 Network registration indicator
9 NETLIGHT modem → ESP32 Blink pattern decoded by ESP32 for LED2 status
10 LTE_TX_BLANK ESP32 → modem WiFi/LTE TX coexistence blanking
11 EXT_DETECT ext → base (P1.12) Extension variant ADC divider
12 Spare -- Reserved for future use
13 Spare -- Reserved for future use
14 Spare -- Reserved for future use

ESP32 Manages LTE Modem

The LTE modem is managed by ESP32, not nRF54 directly. ESP32 already handles IP connectivity (WiFi) -- adding LTE as a second transport is natural. nRF54 sends gateway data to ESP32, and ESP32 routes it via WiFi or LTE. ESP32 also manages WiFi/LTE coexistence (TX blanking). See ESP32 to LTE Modem.

NETLIGHT Blink Pattern

The SIMCom SIM7672 NETLIGHT pin outputs a hardware blink pattern (1.8V logic, level-shifted to 3.3V on the extension board): 64ms/800ms = not registered, 64ms/3000ms = registered, 64ms/300ms = data transfer. ESP32 firmware decodes this pattern and relays LTE status to nRF54 via UART1 for display on LED2 (gateway status SK6812). A development LED on the extension board also taps this signal (at 1.8V, before level shifting) for visual debugging -- see 232210 extension documentation.

3.3 LTE Power Rail

Parameter Value
Source 5V from Power Base Module (direct, not via 3.3V regulator)
Current 2A burst capability
Purpose LTE modem requires high peak current during TX

Design notes:

  • Wide power trace or copper pour from 5V input to board-to-board connector
  • Bulk capacitance near connector to handle modem TX current spikes
  • LTE modem has its own on-module regulator on the extension board

4. Pin-Out (Delta)

Additional GPIO requirements beyond 232203 pin-out:

nRF54 Pins -- Occupancy Sensor (Delta from 232203)

GPIO SAADC Function Direction Notes
P1.11 AIN4 SENSOR_CLK / TX Output SPI CLK or UART TX to sensor (freed from UART1 TX)
P1.13 AIN6 SENSOR_MISO / RX / AIN Input SPI MISO or UART RX or analog PIR (freed from UART1 RX)
P1.14 AIN7 SENSOR_MOSI Output SPI MOSI (freed from ESP32_RESET)
P1.08 -- SENSOR_CS Output SPI CS (freed from SPI accelerometer)
P2.09 -- SENSOR_IRQ Input IRQ / presence detect digital output

Multi-Option Sensor Interface

These 5 pins route to a common sensor footprint area. The BOM determines which sensor is populated. SPI radar uses all 5 pins. UART radar uses P1.11 + P1.13 + P2.09. Analog PIR uses P1.13 (AIN6 for ADC) + P2.09 (digital comparator). I2C sensors share the existing bus (P1.04/P1.05) and use P2.09 for IRQ. All directions are preserved from the 230220 reference design.

ESP32 Pins (LTE Modem -- via B2B Connector)

LTE modem control signals are on ESP32 GPIO, not nRF54. They route through the board-to-board connector to the extension PCB.

Function ESP32 Direction Notes
LTE_UART_TX Output AT commands to LTE modem
LTE_UART_RX Input AT responses from LTE modem
LTE_POWER_KEY Output Modem power on/off
LTE_RESET Output Modem hard reset
LTE_STATUS Input Network registration indicator
NETLIGHT Input Modem blink pattern, decoded for LED2 status
LTE_TX_BLANK Output TX blanking for WiFi/LTE coexistence

5. Component Selection (Delta)

5.1 Occupancy Sensor (Customer-Driven Selection)

Parameter Value
Type TBD -- PIR analog, SPI radar, UART radar, or I2C
nRF54 Interface 5-pin sensor bus (P1.11, P1.13, P1.14, P1.08, P2.09) + optional I2C shared bus
Est. Price $2--8 depending on sensor family

See Section 3.1 Occupancy Sensor Interface for full option comparison, pin mapping, and candidate parts.

5.2 Board-to-Board Connector (Base Side -- Header)

Parameter Value
Manufacturer Harwin
Part Number M20-8750742 (2x7 = 14-pin, vertical SMT, male)
Pitch 2.54mm (0.1")
Mating Pin 5.8mm, 0.64mm square
Current Rating 3A per contact
Stacking Height ~10--11mm mated (with M20-781 socket)
Est. Price ~$0.50--0.80

Rationale: Harwin M20 is a standard 2.54mm pitch connector with excellent sourcing (DigiKey, Mouser, LCSC). The 14-pin count provides 11 assigned signals + 3 spare. The ~10--11mm stacking height fits the enclosure stack-up. DNP on non-LTE variants (232200--232203).

SIM, Antenna, LDO, and Level Shifters on Extension Board

The SIM card holder, on-board chip antenna (Quectel YC0001CA), 3.8V LDO (modem power), 1.8V↔3.3V level shifters, and NETLIGHT dev LED are all located on the extension board (232210/232211). They are not present on this base PCB. See 232210 component selection for details.

6. PCB Design Notes (Delta)

6.1 Board Area

This is the most populated base variant. The PCB designer must verify all components fit within the enclosure PCB outline, accounting for:

  • PAN611 + ESP32-C5 modules (with RF clearance zones)
  • Battery connector and charger circuit
  • PIR/Radar sensor (facing front of enclosure)
  • Board-to-board header (Harwin M20-8750742, positioned for extension board stack-up)

6.2 Extension Board Stack-Up

Parameter Value
Base PCB (232204) Bottom, ~1.6mm thickness
B2B stacking height ~10--11mm PCB-to-PCB
Extension PCB (232210) Top, ~1.6mm thickness, components on top side
Total stack-up ~13--14mm (base PCB + gap + extension PCB)
  • 232204 base PCB on bottom (USB-C male plug protrudes downward / to the side)
  • 232210/232211 extension PCB stacks on top via Harwin M20 B2B connector
  • Extension board components face upward (top side only)
  • SIM card holder on extension board: push-push type, card slot accessible from underneath the extension board (same access side as USB-C on base PCB)
  • Total height must fit within enclosure (232506) internal volume

6.3 Power Routing for LTE

  • 5V power trace to board-to-board header: minimum width for 2A burst
  • Bulk capacitors (>100 uF) near B2B header power pins
  • Separate from sensitive analog/RF signal routing
  • No SIM or RF traces on this base PCB -- all SIM and RF routing is local to the extension board

7. Test Points (Delta)

Additional test points beyond 232203:

TP # Signal Expected Value Notes
TP30 LTE_5V 5.0V Power to B2B header (extension)
TP31 LTE_UART_TX Logic ESP32 → LTE modem (via B2B)
TP32 LTE_UART_RX Logic LTE modem → ESP32 (via B2B)
TP33 PIR_OUT Logic Sensor detection output

232204-Specific Tests

  • PIR/Radar sensor detection test (motion in front of enclosure)
  • Board-to-board header: verify 5V / 2A power delivery to extension board
  • Board-to-board header: verify UART communication through connector to extension modem
  • Board-to-board header: mechanical fit with extension board socket
  • Combined power budget: all subsystems active simultaneously (nRF54 + ESP32 + LTE modem via extension)

8. Revision History

Revision Date Author Changes
Rev A TBD TBD Initial design (not in first PCB iteration)