Hezhou Air780E built-in analog audio solution

The 4G-Cat.1 series modules based on the EC618 platform of Yixin have quickly captured the market with their high performance, low power consumption and ultra-high cost performance.

However, in terms of audio applications, the EC618 platform does not support built-in audio decoder (Codec), which means it does not support analog voice. Therefore, the conventional solution in the industry is to add an external audio chip and audio PA, but this undoubtedly increases the difficulty of R&D and project costs.

So, is there a more convenient and low-cost solution? ——Hezhou Air780E has a new built-in analog audio solution!

Hezhou Air780E built-in analog audio solution

The built-in analog voice output function of the Air780E module is independently developed by Hezhou based on the EC618 platform of Yixin. It converts digital voice into analog voice output through software algorithms, thus making up for the deficiency of the EC618 platform without a built-in audio decoder.

Version support

Please purchase the new version of Air780E module/matching audio development board debugging experience through Hezhou official channels. All versions purchased from March 27, 2023 support built-in analog audio function.

▼ Voice broadcast effect comparison ▼

Implementation principle

Through the module GPIO pin, the software algorithm is used to output the adjusted waveform with different duty cycles, and the filter circuit is used to simulate and restore the sampling voltage of the PCM digital sound source, thereby achieving the effect of digital-to-analog conversion and outputting an analog sine waveform. The output power is then amplified through an external audio power amplifier to achieve a suitable volume.

Development Information

For detailed instructions on how to use the built-in analog audio solution, see "Instructions for Using the Built-in Analog Voice Function of Air780E", related link www.air780e.cn.

Main advantages of the solution

R&D and innovation:

Through independent research and development and innovation, Hezhou took the lead in launching the Air780E module based on the EC618 platform with built-in analog audio output function. It has newly enabled 4G cloud speaker applications and has been verified and tested by multiple industry leading customers, fully promoting the development of the industry.

Cost Savings:

There is no need to use audio decoding chip, independent power supply LDO, external resistors and capacitors, and the entire material cost can be saved by at least 0.7-0.8 yuan (tax included).

Flexible design:

This solution uses software algorithms to implement functions similar to digital-to-analog conversion (DAC), which not only saves the cost of peripheral devices, but also saves the layout space of external audio decoding chips, making product design more flexible.

Easy development:

Provide hardware design reference and support standard AT/ LuatOS / C-SDK diversified development methods.

Wide range of applications:

Users can easily use the built-in analog audio solution of Hezhou Air780E to develop related audio application scenarios, such as: cloud speakers, TTS, security and other voice broadcast related application scenarios.

Hezhou Air780E new audio development board

To facilitate engineers to test and evaluate the built-in analog audio solution of Air780E, Hezhou has specially designed a matching audio development board.

The audio development board is also compatible with various external Codec solutions (such as TM8211, ES7149, ES8311, ES8218E, etc.) for easy debugging and comparison. At the same time, Hezhou LuatOS and C-SDK demo have also made the above Codec solutions into routines to help everyone improve development efficiency.