Discover the Oneplus Neckband BES2300 CPU schematic diagram and pinout connection details. Download now for quick and easy reference to your device.
The BES2300 CPU pinout is arranged in a square format, with pins numbered and labelled around the CPU. Each pin serves a specific function related to power management, data processing, audio input/output, and connectivity. Let’s break down each section, covering the key functions and components connected to these pins.
Power and Voltage Pins
VCORE (H9) - Core Voltage: Supplies power to the core part of the CPU. It’s crucial for the CPU's main operations, providing the necessary power for internal processing.
VBAT (D10) - Battery Voltage: Connects to the battery's positive terminal, providing the primary power supply for the device. All other power-related functions derive from this primary voltage source.
VCHG_R (C9) - Charging Voltage Right: Used for charging functions. This pin connects to the charging circuit to manage incoming power from a USB or charger.
VMEM (B10) - Memory Voltage: Supplies power to the memory units. The stable voltage here is essential for data retention and quick access.
VANA (J8) - Analog Voltage: Powers analogue components such as ADCs (Analog-to-Digital Converters), which convert analogue signals to digital for processing.
VUSB_CAP (K8) - USB Capacitor Voltage: Connects to a capacitor to stabilize the USB power supply.
VUSB (K9)—USB Voltage: This voltage powers USB-related functions, which are necessary for data transfer and charging over USB.
USB and Charging Pins
USB_DN (L10) - USB Data Negative: Acts as the data line for USB connectivity, enabling communication between the CPU and external USB devices.
USB_DP (M10) - USB Data Positive: Works alongside USB_DN for data transmission over USB.
VBAT_SENSE (D9) - Battery Voltage Sense: Measures the battery voltage level, allowing the CPU to monitor battery health and charge status.
LX1 and LX2 (F10, D10) - Part of the DC-DC converter circuit for power management, essential in regulating the power supply.
PGND (E10) - Power Ground: Provides a grounding point for power circuits, ensuring stability in voltage references and noise reduction.
GPIO (General Purpose Input/Output) Pins
GPIO_20, GPIO_21, GPIO_22, etc. (E9, F9, C4) - These pins serve as general-purpose input/output connections. They are used for various control functions, sensor inputs, and connections to external components.
Special GPIO Pins:
GPIO_26 (J9): Often used for specific control functions within the device, depending on the software configuration.
GPIO_27 (L7): Similarly customizable for different functions as needed.
Audio and Microphone Pins
LOUT_RP, LOUT_RN, LOUT_LP, LOUT_LN (B9, B8, A7, B6) - Left/Right Output Positive/Negative: These pins connect to the speakers for audio output. RP and RN correspond to the right channel, while LP and LN correspond to the left channel.
MIC1_P, MIC1_N (A2, A3) - Microphone Positive/Negative: Pins for connecting a microphone. MIC_P connects to the positive terminal of the mic, and MIC_N to the negative.
MIC2_P, MIC2_N, etc. (B2, B3) - Additional microphone inputs for devices with multiple microphones. These support noise cancellation and enhanced audio quality by capturing sound from multiple sources.
Clock and Crystal Pins
XTAL_IN (L2) - Crystal Oscillator Input: Connects to an external crystal oscillator for generating the CPU’s clock signal. This is critical for timing and synchronization.
XTAL_OUT (M1) - Crystal Oscillator Output: Works with XTAL_IN to stabilize the clock signal, providing precise timing control within the CPU.
Analog-to-Digital Converter (ADC) Pins
ADC0, ADC1/LED2 (E6, G7) - Analog-to-Digital Converters: Converts analogue signals (like sensor inputs) to digital form. ADC1/LED2 may also serve as an LED control pin depending on configuration.
REFN_R, REFN_L (F5, F6) - Reference Ground for ADC: Provides stable ground reference points for the ADC to ensure accurate signal conversion.
Pin Functions and Component Connections
Battery Connection:
Connect VBAT (D10) to the positive terminal of the battery.
Ground connections are made to PGND (E10).
VBAT_SENSE (D9) is used for monitoring battery voltage, connecting to the positive terminal of the battery through a resistor divider if needed.
Microphone (MIC) Connection:
For a single microphone, connect the positive terminal to MIC1_P (A2) and the negative terminal to MIC1_N (A3).
Multiple microphones can be connected to MIC2 or MIC3 pins, allowing stereo sound or noise-cancellation capabilities.
Speaker (SPK) Connection:
LOUT_RP (B9) and LOUT_RN (B8) connect to the right speaker.
LOUT_LP (A7) and LOUT_LN (B6) connect to the left speaker.
Ensure that each channel has both a positive and negative connection to avoid grounding issues.
Charging and USB Connection:
Connect the USB connector’s data lines to USB_DP (M10) and USB_DN (L10) for data transfer.
VUSB (K9) and VUSB_CAP (K8) are used for stabilizing and supplying voltage during USB charging.
The charging voltage enters through VCHG_R (C9) and is regulated by internal circuitry for safe battery charging.
Crystal Oscillator (Clock) Connection:
A 24 MHz crystal oscillator is typically connected to XTAL_IN (L2) and XTAL_OUT (M1).
This clock signal is crucial for the CPU to synchronize internal operations and manage time-sensitive tasks.
ADC Sensor Inputs:
Sensors producing analogue outputs can be connected to ADC0 (E6) and ADC1 (G7), allowing the CPU to process environmental data.
Use REFN_R (F5) and REFN_L (F6) for stable grounding references to maintain accurate ADC readings.
LED Indicators:
Connect LEDs to LED1 (D8) and LED2 (G7). These pins can be programmed to indicate charging status, Bluetooth connection, or battery level.
Ground Pins (GND):
Pins F5, G5, H5, etc. are grounding points for different parts of the circuit, stabilizing voltages and preventing signal interference.
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