WONDOM ADAU1701 2.1 DSP Audio Digital Processing Pre-Amp Volume Control Board User Manual

1. Introduction

The WONDOM ADAU1701 Digital Signal Processor Kernel Board, model APM2 (AA-AP23122), is a high-performance 2-input, 4-output DSP module based on the Analog Devices ADAU1701 chip. This board is designed for various audio applications, including digital crossovers, bass enhancement, and general audio system control.

The APM2 features an integrated debug port, allowing programming via SigmaStudio software using an original USBi or WONDOM ICP programmer. It also supports remote control through a dedicated APP or PC UI. Four on-board potentiometers provide real-time hardware control for gain and cut-off frequency adjustments, enabling users to fine-tune audio output to match specific listening environments and speaker configurations.

For enhanced connectivity, an optional 2-input, 3-output Interface Extension Board (APM3) is available, offering various input and output interfaces such as RCA jacks, 3.5mm AUX IN, and PH-4Pos line input/output connectors. Both APM2 and APM3 are compact (2x2 inches), facilitating easy integration into diverse projects like Kiosks, Speaker Equalization systems, Active Crossovers, Digital Car Audio Systems, Home Theaters, Karaoke setups, and Musical Instruments.

Figure 1: Top view of the WONDOM APM2 (AA-AP23122) DSP Kernel Board.

2. Key Features

• Equipped with ADAU1701 Chip
• 28/56 bit Digital Signal Processor Engine
• 24-bit ADC/DAC Resolution
• 48kHz Sample Rate
• On-board Potentiometers for audio system control
• 5V USB Type-C Power Input
• Supports SigmaStudio Programming (USBi or ICP)
• Compact Size & Light Weight (2 x 2 inches PCB)
• Supports 2-input, 3-output Interface Extension Board (APM3)

3. Specifications

4. Setup and Connections

4.1. APM2 Pin Definitions

The APM2 board features several connectors for power, audio extension, and programming. Refer to the following tables for detailed pin definitions.

Power Supply Connector (J2)

The J2 connector is a 5V USB Type-C port for power input.

Programming Connector (J11)

J11 is a PH-6pos-2mm connector used for programming or remote control with a WONDOM ICP programmer.

Audio Extension Connector (J1)

J1 is a PH-10pos-2mm connector for connecting to the APM3 Interface Extension Board.

Extension Port (J3)

J3 is a 20-pin extension port for various signals, including analog audio inputs, I2C, digital-to-analog converter outputs, and multi-purpose input/output pins (MPx).

Extension Port (J4)

J4 is another 20-pin extension port for various signals, including power input, multi-purpose input/output pins (MPx), and Master Clock Input (MCLK).

4.2. APM3 Interface Extension Board Connections

The optional APM3 board simplifies audio connections. It provides various input and output interfaces. Note that the stereo input methods (RCA, 3.5mm AUX IN, and Line Input) cannot be used simultaneously. Similarly, the stereo output methods (RCA, headphone, and line output) are connected in parallel and cannot be used at the same time.

Figure 2: WONDOM APM3 Interface Extension Board, showing 2-in, 3-out capabilities.

Audio Input Connectors (APM3)

• J1: 3.5mm AUX IN
• J2, J5: RCA Jack (J2 for Input L, J5 for Input R)
• J3: PH-4pos-2mm Line Input

Audio Output Connectors (APM3)

• J7: 3.5mm Headphone Output
• J6, J9: RCA Output (J6 for Output R, J9 for Output L)
• J10: RCA for Subwoofer Output
• J8: PH-4pos-2mm Line Output

4.3. Audio Input and Output (APM2)

The APM2 supports stereo analog input via pins 1 (AINL) and 3 (AINR) of J1, or pins 1 (AD0) and 2 (AD1) of J3. In the SigmaStudio demo program, 0 (ADC_IN0) and 1 (ADC_IN1) of the input module are used for stereo input.

For audio output, APM2 supports 2-input, 4-output configuration. The hardware outputs are pins 5, 6, 7, 8 (OUTR1, OUTL1, OUTR2, OUTL2) of J1 and OR1, OL1, OR2, OL2 pins of J3. These correspond to DAC0, DAC1, DAC2, DAC3 output modules in the SigmaStudio program. Note that the APM3 interface extension board only supports 2-input, 3-output.

4.4. I2S Input and Output Configuration

When configuring I2S input and output, it is crucial to determine the master-slave mode of your device and the MCLK configuration. A flowchart is provided in the official user manual (APM2UserManual.pdf) to guide this process.

If your device is in Master Mode and needs MCLK, connect the MCLK pin of your device to pin 1 of APM2 Y1. If your device is in Slave Mode and has MCLK, remove the crystal oscillator from APM2 and connect the MCLK pin of your device to pin 1 of APM2 Y1. If your device does not need MCLK, no connection is required.

For I2S input, connect LRCLK, BCLK, DATA, GND, and MCLK signals from your source device to the corresponding MPx pins on APM2's J4 extension port. For example, MP4 for LRCLK_in, MP5 for BCLK_in, and MP0 for Input Sdata. The SigmaStudio program configuration involves setting the respective MPx pins to the correct input functions (e.g., Input Sdata_in0, Input Lrclk_in, Input Bclk_in).

For I2S output, connect LRCLK, BCLK, SDATA, GND, +3.3V, and MCLK signals to your receiving device from the corresponding MPx pins on APM2's J4 extension port. For example, MP6 for Output Sdata, MP10 for LRCLK_out, and MP11 for BCLK_out. The SigmaStudio program configuration involves setting the respective MPx pins to the correct output functions (e.g., Output Sdata_out0, Output Lrclk_out, Output Bclk_out).

5. Operation

5.1. Potentiometer Control

The APM2 board features four on-board potentiometers (POT1-POT4) for real-time adjustment of audio parameters:

• POT1: Bass Gain Adjustment (Mapped to AUX_ADC_0 / MP9)
• POT2: Cut-off Frequency of Bass (Mapped to AUX_ADC_3 / MP8)
• POT3: Cut-off Frequency of Treble (Mapped to AUX_ADC_2 / MP3)
• POT4: Overall Gain Adjustment (Mapped to AUX_ADC_1 / MP2)

The adjustable range for the cut-off frequency of treble is typically 250Hz-2kHz. For bass, the lower cut-off frequency range is 60Hz-120Hz, and the upper cut-off frequency range is 200Hz-400Hz.

5.2. External Potentiometers

For external control, you can connect external potentiometers to the MP2, MP3, MP8, and MP9 pins of J3. Ensure you lead out +3.3V, GND, and the corresponding potentiometer pin. When using external potentiometers, the on-board potentiometers must first be set to their maximum value to allow full range control from the external ones.

5.3. Software Control (SigmaStudio & APP)

The APM2 supports programming and real-time control via SigmaStudio software. You can use an original USBi or WONDOM ICP programmer for this purpose. WONDOM also provides an APP or PC UI for remote control of the audio system, which requires connection with an ICP programmer.

Open-sourced demo programs are available for reference. When using the ICP5 with SigmaStudio, it is recommended to use and modify the provided demo programs. Instructions for ICP5 usage and demo programs can be found in the ICP5.pdf file (if available, otherwise contact customer service).

Figure 3: The APM2 supports multiple control methods, including SigmaStudio programming and PC UI control.

6. Maintenance

• Keep the board in a dry environment to prevent moisture damage.
• Avoid exposing the board to extreme temperatures.
• Handle the board with care to prevent physical damage to components or connectors.
• When making connections, ensure the power is off to prevent short circuits or damage.
• Clean the board gently with a soft, dry cloth if necessary. Do not use liquids or harsh chemicals.
• Protect the board from electrostatic discharge (ESD) by using appropriate handling procedures.

7. Troubleshooting

• No Power: Ensure the 5V USB Type-C power supply is correctly connected and providing sufficient current. Check the USB cable and power source.
• No Audio Output:
  • Verify all audio input and output connections are secure and correctly wired.
  • Confirm the correct input method is selected if using the APM3 extension board (only one input method can be active at a time).
  • Check the SigmaStudio program for correct signal flow and output routing.
  • Ensure potentiometers are not set to minimum or mute.
• Programming Issues:
  • Ensure the WONDOM ICP programmer or USBi is correctly connected to J11.
  • Verify that SigmaStudio software is properly installed and configured.
  • Check for driver issues with the programmer.
  • Refer to the ICP5.pdf (if available) for specific programming troubleshooting.
• I2S Communication Problems:
  • Double-check the master-slave mode configuration and MCLK connections as per the I2S setup instructions.
  • Verify pin connections for LRCLK, BCLK, and DATA signals on J4.
  • Ensure the SigmaStudio program has the correct I2S input/output settings.
• Unexpected Audio Behavior:
  • Review your SigmaStudio program for any unintended processing blocks or parameter settings.
  • If using external potentiometers, ensure the on-board potentiometers are set to maximum.

8. User Tips

• Standalone DSP: The APM2 functions as a standalone DSP and interfaces directly with SigmaStudio using an appropriate programmer (USBi or WONDOM ICP).
• Power Supply: While the board requires 5V USB Type-C power, ensure your power supply can provide sufficient current for the entire audio system, especially if driving other components. A typical USB port provides 500mA, which may not be enough for a full system.
• Audio Input Voltage: The board is designed for line-level audio signals. Avoid feeding excessively high voltage signals to prevent damage.
• Demo Programs: The provided open-sourced demo programs are for demonstration of signal flow only and are not original settings programs. They serve as a starting point for your custom configurations.
• APM3 Input/Output: Remember that on the APM3 extension board, the multiple input methods cannot be used simultaneously, and the multiple output methods are connected in parallel, meaning only one type should be actively used at a time.

9. Warranty and Support

All WONDOM Audio Amplifier boards, including the APM2, comply with RoHS standards and are pre-tested to ensure compatibility with FCC and CE regulations. Certifications can be provided upon request for bulk purchases.

For technical support, inquiries, or to request certifications, please contact Sure Electronics Co., Ltd. using the information below:

• Email: info@sure-electronics.com
• Website: store.sure-electronics.com / www.wondom.com
• Skype: surewebstore
• Address: NO.9, Weidi Road, Xianlin University City, Qixia District, Nanjing, Jiangsu Province, P.R.C