---
title: Compile-Time Configuration (sdk_sgr_config.h)
description: Compile-Time Configuration (sdk_sgr_config.h)
---
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October 6, 2026
# Compile-Time Configuration (sdk\_sgr\_config.h)
**Who this is for:** Developers who need to understand or change how the SDK is built.
**What you'll accomplish:** Understand each compile-time parameter, what it controls, and which ones you must set intentionally for production.
**These take effect at compile time.** Changing them means rebuilding (`make clean && make`). Several can also be overridden from the build system with a `-D` flag, noted below.
### Parameters in `sdk_sgr_config.h`
#### `SDK_MODE`
Selects `DEVICE_MODE` or `GATEWAY_MODE`, which functions and port implementations are compiled in. **If undefined, the build fails with a compile-time error.** See *Device Mode vs Gateway Mode*.
#### `GW_CRYPTO_ENABLED`
Whether the Gateway requires its own crypto Token via USB/SPI. Default: **not required**. Has no effect in `DEVICE_MODE` (the Token is always required there).
#### `MAX_RETRIES` / `GW_MAX_RETRIES`
Device-side and gateway-side retry limits. Validated at compile time; a minimum is enforced with a compiler warning.
#### `CW_BITFLIP_THRESHOLD` / `RW_BITFLIP_THRESHOLD`
Tolerated bit differences when comparing Challenge/Response Words. **Lower = stricter, higher = more tolerant.**
A value of `0` means any single bit difference triggers Error Management / immediate failure. That's valid, but **set it intentionally**, it's not a safe default to leave unexamined.
#### `CRC_ENABLE`
Message CRC integrity checking.
- **Disabled (`0`) by default in this branch** for local testing.
- **Mandatory outside local testing.** Enable it with `-DCRC_ENABLE=1`.
- A mismatch produces `SGR_SDK_CRC_ERROR`.
### Debug flags (six, independent)
`MW_DEBUG`, `PORT_COMM_DEBUG`, `PORT_COMM_INPUT_DEBUG`, `PORT_COMM_DEVICE_DEBUG`, `APP_GW_DEBUG`, `MW_GW_DEBUG`. Each can be overridden from the build system (e.g. `-DMW_DEBUG`).
#### **Important: don't edit the core files**
The default values live in files you should **not** edit:
- `poc_sdk_device/sdk_fw/include/sdk_sgr_config.h`
- `poc_sdk_gateway/sdk_fw/include/sdk_sgr_config.h`
More broadly, the `sdk_fw/` core directory should not be modified, with the single exception of `src/services/database/auth_db_whitelist.c` (the device whitelist). To change behavior, pass `-D` flags at build time rather than editing these headers.
### Production checklist
Before shipping a production build:
- \[ \] **Disable all debug flags.**
- \[ \] **Enable CRC** (`-DCRC_ENABLE=1`).
- \[ \] **Set bit-flip thresholds explicitly** and intentionally.
- \[ \] Keep secret keys inside the crypto chip (never exposed by the SDK).
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