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IC Brand: JL (Jieli)
IC Number: BP1X623-66B4, BP24895-66B4
IC Total Pins: 32 + Main Groun 1 Pin
Pin Configuration and Functions
AGND (Pin 1) - Analog Ground
This is the analogue ground pin of the IC. It is connected to the ground plane to ensure stable analogue signals by reducing noise interference. The analogue ground is essential in handling sensitive audio signals.
VCOM (Pin 2) - Common Voltage
VCOM acts as a reference voltage, commonly used for analogue functions inside the IC. It is connected to a capacitor (C19) to filter out any noise and ensure a stable reference.
DACL (Pin 3) - Digital-to-Analog Converter (Left Channel)
This is the DAC output for the left audio channel. It is connected to the audio output stage, enabling the IC to output audio signals after converting from digital to analogue. This output is used for stereo audio output.
DACR (Pin 4) - Digital-to-Analog Converter (Right Channel)
Similar to DACL, DACR is for the right audio channel. Together, DACL and DACR form the stereo audio output of the IC.
AUX L/R (Pin 5) - Auxiliary Audio Input
AUX L/R allows the IC to receive external analogue audio input. This is useful in Bluetooth audio devices that can switch between Bluetooth audio and wired audio input.
SD CLK (Pin 6) - SD Card Clock
This pin is used as the clock line for the SD card interface. It is necessary when the IC reads data from an external SD card.
SD CMD (Pin 7) - SD Card Command
This is the command pin for communication with an SD card, allowing the IC to send and receive data to/from the card.
SD DAT (Pin 8) - SD Card Data
This pin carries data between the IC and the SD card. It supports the data transfer essential for music playback from an SD card.
LDO IN (Pin 9) - Low Dropout Regulator Input
LDO_IN supplies input power to the internal low-dropout (LDO) regulator. This regulator provides a stable voltage to other parts of the IC.
PB7/SDDCLKF/AUX1R/ADC9 (Pin 10) - Multi-Function Pin
This pin has multiple uses, functioning as a general-purpose I/O, SD card data clock, auxiliary input, and ADC channel. The specific use depends on the configuration and operating mode of the IC.
PB6/SDCMD/F/AUX1L/ADC8 (Pin 11) - Multi-Function Pin
Similar to Pin 10, this pin can serve as an I/O pin, SD card command line, auxiliary input, or ADC input.
PB4/SDDATAF/ADC7 (Pin 12) - Multi-Function Pin
This pin can be used as SD card data, general-purpose I/O, or ADC channel 7.
VBAT (Pin 13) - Battery Voltage
VBAT connects to the battery, supplying power to the IC. This pin is essential for the IC’s operation, especially in battery-powered devices.
PB3/SDDATA0/ADC6 (Pin 14) - Multi-Function Pin
This pin serves as an SD data line, general-purpose I/O, or ADC channel.
PB2/SDDATA1/ADC5 (Pin 15) - Multi-Function Pin
Similar to the previous pin, it acts as an SD data line, I/O, or ADC input.
PB1/SDDATA2/ADC4 (Pin 16) - Multi-Function Pin
It can be configured as an SD data line, general-purpose I/O, or ADC channel.
PB0/SDDATA3/ADC3 (Pin 17) - Multi-Function Pin
This pin serves similar purposes, configurable as an SD data line or I/O.
BT_OSC1 (Pin 18) - Bluetooth Oscillator Input
BT_OSC1 is the oscillator input pin for the Bluetooth module, essential for generating the clock signals needed for Bluetooth operation.
BT_OSC2 (Pin 19) - Bluetooth Oscillator Output
This is the complementary oscillator output for Bluetooth operation, forming a pair with BT_OSC1.
BT_RF (Pin 20) - Bluetooth RF Antenna
BT_RF connects to the Bluetooth antenna circuit (L8, L9, C22), enabling Bluetooth signal transmission and reception.
FM_RF (Pin 21) - FM Radio RF Antenna
This pin is used as the input for the FM radio antenna. Components such as L2, C2, and L3 form the FM input circuit, which enables the IC to receive FM signals.
FM_ANT (Pin 22) - FM Antenna
FM_ANT is another connection for the FM antenna, used alongside FM_RF to receive FM radio signals.
USB_DM (Pin 23) - USB Data Minus
USB_DM is the data line for USB communication. It allows data transfer between the IC and external devices via USB.
USB_DP (Pin 24) - USB Data Plus
USB_DP works with USB_DM for USB communication.
BAT_DET (Pin 25) - Battery Detection
BAT_DET monitors battery voltage, allowing the IC to detect battery status and manage power accordingly.
CS3 (Pin 26) - Chip Select 3
This pin can be used to select an external device for communication, often used in SPI or similar interfaces.
CS2 (Pin 27) - Chip Select 2
Similar to CS3, this pin selects an external communication device, allowing the IC to interact with multiple peripherals.
CS1 (Pin 28) - Chip Select 1
Another chip selects a pin for communication with external devices.
SPI1DIB/SDDATA4/PC3 (Pin 29) - Multi-Function Pin
This pin can act as an SPI input, SD data, or GPIO depending on the configuration.
SPI1DIA/SDDATA5/PC4 (Pin 30) - Multi-Function Pin
Another configurable pin for SPI data, SD data, or GPIO use.
SPI1DO/SDDCLK/PC5 (Pin 31) - Multi-Function Pin
This pin serves as an SPI output or SD card clock.
ADC12/SPI1DOB/SDDCKLK/PC6 (Pin 32) - Multi-Function Pin
This multi-purpose pin can act as an ADC input or an SPI data line.
Circuit Connections and Working
The AC6966B IC is at the heart of Bluetooth audio circuits, managing everything from audio processing to Bluetooth transmission. Here's a summary of how some of the key sections work:
Audio Processing: Audio signals enter through AUX L/R, and the DAC outputs (DACL, DACR) are used for stereo audio output. This enables audio playback through Bluetooth or SD card.
Bluetooth Functionality: The Bluetooth oscillator pins (BT_OSC1 and BT_OSC2) generate the required frequency for Bluetooth. The BT_RF pin connects to an antenna circuit (L8, L9, C22) to enable Bluetooth communication.
Power Management: The IC is powered through VBAT and has built-in battery detection (BAT_DET) to monitor battery levels. LDO_IN powers internal circuits, ensuring stable voltage regulation.
SD Card Functionality: SD CMD, SD CLK, and SD DAT pins facilitate data transfer with an external SD card, allowing music playback from the card.
USB Communication: USB_DM and USB_DP allow the IC to communicate over USB, enabling features like firmware updates or charging management.
FM Radio Reception: FM_RF and FM_ANT are connected to an external FM antenna circuit (C20, L3, and C21), enabling the IC to receive FM radio signals.
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