Application note from NXP Semiconductors introduces a wireless gamepad solution based on LPC5528 and NxH3670. Link here (PDF)
LPC5528 is a Cortex®-M33 based microcontroller for embedded applications. It has two USB device controllers which are key peripherals for the gamepad solution: Full-speed USB and High-speed USB device controllers. All of these features make LPC5528 very suitable as a gamepad or headset host controller. NxH3670 is a ultra-low-power 2.4 G wireless transceiver. It integrates a Cortex-M0 processor and has passed the Bluetooth Low Energy 4.2 certification. It has low latency and low power consumption characteristics and is used in wireless gaming headset products.
The main functions implemented are as follows:
• Wireless mode
USB cables are not required to connect PC (game console) and gamepad.
• Wired mode
When the battery of gamepad is exhausted or there is no USB dongle module, the gamepad can be connected to the PC (game console) through a USB cable to make the gamepad work in wired mode and charge the battery.
• Audio playback and recording function
When the gamepad is working in wireless mode, the audio data on the PC is transmitted to dongle board through the USB interface, and then the audio is transmitted to the gamepad through the NxH3670 for playback. The gamepad can also transmit microphone data to the PC.
• USB VCOM and OTA upgrade function
During the OTA upgrade process, the PC sends the new firmware to the dongle board via USB VCOM. Then, the dongle forwards the firmware to the gamepad. This new firmware will be written to the specified flash address.