> For the complete documentation index, see [llms.txt](https://dev.solid-run.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dev.solid-run.com/solidsense/solidsense-other-articles/solidsense-n8-ble-module-variants.md).

# SolidSense N8 BLE Module Variants

* [Intro](#intro)
* [Hardware Variants & PCB Revisions](#hardware-variants-pcb-revisions)
* [SKU-to-Module Mapping](#sku-to-module-mapping)
* [Firmware Options & Defaults](#firmware-options-defaults)
* [UART Pinout Differences (Developer Critical)](#uart-pinout-differences-developer-critical)
* [Schematics & Hardware Resources](#schematics-hardware-resources)

## **Intro**

This page documents the two BLE module options used across SolidSense N8 hardware revisions, how they map to SKUs, and the key UART pin differences developers must consider. It also links to the module schematics and provides migration notes between PCB revisions.

***

## Hardware Variants & PCB Revisions

* **Legacy N8 (PCB ≤ v1.3):** populated with **u-blox NINA-B1**.
* **Current N8 (PCB v1.4+):** populated with **Fujitsu FWM7BLZ22**.

Both variants are functionally compatible at the system level but differ in BLE module and UART pin mapping.

***

## SKU-to-Module Mapping

* **SRG40x.01SD** (x ∈ {1, 2, 5, 6, 7}) → **u-blox NINA-B1**
* **SRG40x.02SD** (x ∈ {1, 2, 5, 6, 7}) → **Fujitsu FWM7BLZ22**
* Example:
  * **SRG0405.01SD** — N8 Compact with Wi-Fi, BLE-**u-blox**, LTE, RS485, CAN, ETH-Atheros
  * **SRG0405.02SD** — N8 Compact with Wi-Fi, BLE-**FWM7BLZ22**, LTE, PoE, RS485, CAN, ETH-ADIN

{% hint style="info" %}
**Note:** **“.02SD”** SKUs ship FWM7BLZ22 with **BLE firmware** by default. **“.02SW”** SKUs (e.g., `SRG40x.02SW`) ship with **Wirepas** firmware.
{% endhint %}

***

## Firmware Options & Defaults

* **NINA-B1:** BLE stack as per u-blox defaults.
* **FWM7BLZ22:**
  * **.02SD** → BLE firmware by default.
  * **.02SW** → Wirepas firmware preloaded.\
    If a different firmware load is required, specify at order time.

***

## UART Pinout Differences (Developer Critical)

| Module            | UART\_0\_TX | UART\_0\_RX | UART\_0\_RTS | UART\_0\_CTS |
| ----------------- | ----------- | ----------- | ------------ | ------------ |
| u-blox NINA-B1    | 6           | 5           | N.C.         | PD           |
| Fujitsu FWM7BLZ22 | 6           | 8           | N.C.         | PD           |

**Legend:** N.C. = Not Connected, PD = Pulled Down.\
**Impact:** If migrating from NINA-B1 to FWM7BLZ22, update any pin mappings that reference UART0 RX (pin 5 → pin 8).

***

## Schematics & Hardware Resources

* **NINA-B1 Module Schematic**

![image-20250814-103121.png](/files/nS8NDF6oDROTAlzeTX5T)

TX/RX Nordic pin number

**UART\_TX** on pin **6** and **UART\_RX** on pin **5**

![image-20250814-103414.png](/files/uL4ao8YGyt8wfMOy3IPH)

* **Fujitsu** **FWM7BLZ022W Module Schematic**\
  ![image-20250814-103035.png](/files/Ft06IArBScIMuXaIvE8O)

TX/RX Nordic pin number

**UART\_TX** on pin **6** and **UART\_RX** on pin **8**

![image-20250814-093728.png](/files/4CtVYCgDcauWry4nqYRV)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://dev.solid-run.com/solidsense/solidsense-other-articles/solidsense-n8-ble-module-variants.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.