The design skills of gaming keyboard, mouse and headset based on NXP Cortex M33 LPC55S26 are revealed

This solution uses the NXP Cortex M33 LPC55S26 to design an industry-standard reference design, and makes a matching solution for the Anti Ghost Key of the gaming keyboard, the 2K Report Rate of the mouse, and the Hi-Res of the headset.

Real photo of the development version of the gaming keyboard, mouse and headset three in one.

Reference design features 1 (2K Report Rate ):

We use Mouse Rate Checker of the public web software to measure USB data up to 2K report rate.

Reference design features 2 (Key Scan solution):

The LPC55 MCU uses an internal hardware accelerator to assist in determining the Key Scan. It uses Port0 design, which can set the pins according to the key hardware specifications selected by the developer and play a higher performance. Ram will report which keys are pressed or Release, and the delay time for pressing or releasing can also be set internally to achieve the best return performance. The hardware accelerator assists in the Key Scan function without occupying the core of the LPC55 M33, achieving a return every 500us.

Reference design features 3 (Audio Hi-Res ):

The LPC55 MCU has four sets of I2S, which can be designed for earphones and microphones for the external Codec DAC, and can support up to 32 Bit 384KHz USB Audio. The 16Bit 192K Codec DAC and AMP IC on the board can enjoy Hi- The sound quality of Res.

Reference design feature 4 (Active RGB LED ):

► Scenario application diagram

► Showcase photos

► Scheme block diagram

► Core technical advantages

1. Related software and hardware design, which can provide customers with rapid development 2. LPC55Sxx hardware accelerator development design, which can assist in the use of Key Scan 3. LPC55Sxx corresponding to PixArt PMW3389 optical sensor design and program 4. LPC55Sxx I2S design can be targeted Different Audio Res do different corresponding 5. Active RGB LED related design, and related DMA control mode 6. Follow-up with other boards for extended development

► Solution specifications

MCU specifications: 1. The LPC552x / S2x MCU series further expands the world's first Cortex-M33-based general-purpose MCU series, providing developers with significant advantages, including pin, software and peripheral compatibility, while leveraging economy Efficient 40nm NVM process technology 2. 256 kB on-chip flash program memory with flash accelerator and 256 byte page erase and write functions; total SRAM is 144 kB 3. With 23 channels and up to 22 programmable Trigger DMA0 controller, able to access all memories and peripherals with DMA; DMA1 controller with 10 channels and up to 16 programmable triggers, able to access all memories and peripherals with DMA 4. Flexcomm interface Contains up to 9 serial peripherals. Each Flexcomm interface can be selected as USART, SPI, I2C and I2S interfaces through software. The I2C bus interface supports Fast-mode and Fast-mode Plus, its data rate is up to 1Mbit/s, and has multiple address recognition and monitoring modes. 5. USB has a high-speed mode of USB PHY 6. Security: PRINCE, CASPER, AES- 256, physical unclonable function (PUF), secure GPIO, secure boot support, random number generator (RNG) 7. Package: HLQFP100 (14 mm * 14mm), HTQFP64 (10 mm * 10mm), VFBGA98 (7mm * 7mm)

Optical Gaming Navigation Chip specifications: 1. Wired high-end gaming mouse chip designed to provide high-speed, high-precision and high-resolution 2. Using 16-pin dual in-line lead-frame DIP (molded lead-frame DIP) package, And built-in 850nm infrared LED light 3. Can customize the lifting detection height of 2mm or 3mm, and support manual correction of the lifting detection height 4. Can be used with the original LM19-LSI lens for best performance 5. Resolution (cpi) / Frame rate (fps): 16000 6. Tracking speed (ips ): 400 7. Acceleration (g ): 50

Audio specifications: Stereo output w/ 9-band EQ (Codec DAC ): 1. SWD sound widening DSP 2. Sampling rate: 44.1 K, 48 K, 88.2 K, and 96 K (192K) ※ Sampling rate 192 K (playback only ) 3. Resolution: 16, and 24 bit 4. SNR: 90 dB 、 THD+N: -75dB 5. Low-pass, High-pass, Band-pass filters

Mono mic input (Codec ADC): 1. Sampling rate: 48K, 88.2K, and 96K 2. Internal Mic-bias out 3. Side-tone mixer 4. THD+N: -70dB(when input 200mVp-p) 5. SNR: 106 dB

Headphone Amplifier specifications: 1. AVDD 3.3V only needs a single power supply to work 2. Selectable gain -6dB, 0dB, +3dB, +6dB 3. EN pin for MUTE, De-POP control 4. POP noise -72 dB