Update README to reflect current repository status.

Author: pi-anl

README.md

@@ -1,5 +1,41 @@
 # NXP MCU Driver
 
-This repository contains a copy of MCU peripheral library, original sources are obtained from `https://www.nxp.com`
+This repository contains a trimmed-down version of NXP's MCUXpresso SDK peripheral drivers for use with MicroPython.
+
+## Overview
+
+This repository follows the structure of the official [NXP MCUX SDK](https://github.com/nxp-mcuxpresso/mcux-sdk) but includes only the driver files needed for supported target chips, reducing the size from approximately 1.6GB to under 100MB.
+
+The repository is designed to be included as a Git submodule in projects like [MicroPython](https://github.com/micropython/micropython) that target i.MX RT and other NXP MCU families.
+
+## Updating to Newer SDK Versions
+
+The `update_sdk.py` script automates updating driver files from the official NXP MCUX SDK releases:
+
+```bash
+# Update to the latest SDK release
+./update_sdk.py
+
+# Update to a specific release tag
+./update_sdk.py --release MCUX_2.16.0
+```
+
+The script downloads the specified SDK release, updates existing target chip drivers, and commits the changes to a new branch.
+
+## Adding Support for New Chips
+
+To add a new target chip:
+
+1. Create an empty folder with the chip name in `sdk/devices/`
+2. Run `./update_sdk.py` to populate it with drivers from the latest SDK
+
+The automation tool will detect the new target and include it in future updates.
+
+## Current SDK Version
+
+The current SDK version is stored in `sdk/version.txt`.
+
+## History
+
+This repository was originally maintained at [hathach/nxp_driver](https://github.com/hathach/nxp_driver) as part of the TinyUSB project. When TinyUSB migrated to using the official NXP SDK directly, this trimmed version was forked to the MicroPython organization to continue serving projects requiring a smaller dependency footprint.
 
-This repository is meant to be included as submodule and conveniently run [Tinyusb](https://github.com/hathach/tinyusb) examples.