Voice Recorder/Playback Module using ISD1760

16 October 2020 - 0 Comments

ISD1760 Voice Recorder/Playback Module

ISD1760 Voice Recorder Pinout

ISD1760 is a small Voice Recorder/Playback module that can do the multi-segment recording. The user can achieve a high quality of recording for each application with the adjustment of the on-board resistor (4k to 12k). This Voice Recorder/Playback module is designed to operate in two-mode standalone or microcontroller-based SPI mode. Additionally, it has a special feature that is vAlert (voice alert), which can be used as a message indicator, such as Start Record, Stop Record, Erase, Forward, Global Erase, etc.

Pin Description of ISD1760 Voice Recorder/Playback Module

Pin Name	Description
LED	LED turns on during recording and blinks LED during playback, forward, and erase operations
RST / RESET	RST input is Low, the device enters into a known state and initializes all pointers to the default state.
GND	Ground
VCC	2.4V - 5.5V (5.0V Nominal)
MISO	Master In Slave Out: Data is shifted out on the falling edge of SCLK.
MOSI	Master Out Slave In: In SPI slave mode, data is latched into the device on the rising edge of SCLK.
SCLK	Serial Clock: Clock of the SPI interface.
SS	Slave Select: This input, when low, selects the device as a slave device and enables the SPI interface.
GND	Ground
AnaIn	AnaIn: Auxiliary analog input to the device for recording or feed-through.
MIC	Microphone signal Input
SP-	Speaker(-): The negative Class D PWM provides a differential output with SP+ pin to directly drive an 8 Ω speaker
SP+	Speaker(+): The positive Class D PWM provides a differential output with the SP- pin to directly drive an 8 Ω speaker
AUD/AUX	Auxiliary Output: Depending upon the D7 of APC register, this output is either an AUD or AUX output. AUD is a single-ended current output, whereas AUX is a single-ended voltage output.
GND	Ground
VCC	2.4V - 5.5V (5.0V Nominal)
VOL	Volume: This control has 8 levels of volume adjustment.
FT	Feed-through: In Standalone mode, when FT is engaged low, the AnaIn feed-through path is activated.
PLAY	Playback: Pulsing PLAYto Low once initiates a playback operation.
REC	Record: The device starts recording whenever REC switches from High to Low and stays at Low.
ERASE	Erase: When active, it starts an erase operation.
FWD	Forward: When triggered, it advances to the next message from the current location, when the device is in power-down status.

Note: Complete technical details can be found in the ISD1760 Datasheet linked at the bottom of this page. A complete technical design guide can be found in the ISD1760 Design Guide.

Alternatives for ISD1760: ISD1820, ISD1700

Features of ISD1760 Voice Recorder/Playback Module

Operating Voltage: Wide power supply ranges from 2.4V to 5.5V DC
Dual operating modes: Standalone mode and SPI mode
Two individual input channels
MIC input with AGC (Automatic Gain Control)
AnaIn (Analog input)
Dual output channels
Differential PWM Class D speaker outputs
Configurable AUD (current) or AUX (voltage) single-ended output
Non-volatile message storage using multi-level storage (MLS)
High-quality, natural voice, and audio reproduction
Integrated message management systems for single-chip, push-button applications
Dimensions(LxWxH) in cm 6 x 6 x 2

ISD1760 Voice Recorder/Playback Module - Overview

The main Voice Recorder/Playback IC is ISD1760.

This ISD1760 Voice Recorder/Playback Module reproduces high-quality, natural voice and audio from the recorded audio by Mic or SPI or Analog Input. Because of its dual operation mode (Standalone and SPI), we can easily use this as per requirement and with a slight change of the onboard resistor, we can get flexibility in the sampling frequency of the recording duration & quality.

Sample Frequency	ISD1760
12 kHz	40 Secs
8 kHz	60 Secs
6.4 kHz	75 Secs
5.3 kHz	90 Secs
4 kHz	120 Secs

In this module, Voice signals can be fed through two independent paths, namely, a differential microphone input or a single-ended analog input. For outputs, the module provides a Pulse Width Modulation (PWM) Class D speaker driver and a separate analog output simultaneously. The PWM can directly drive a standard 8Ω speaker or typical buzzer, while the separate analog output can be configured as a single-ended current or voltage output to drive an external amplifier.

Interfacing diagram

The ISD1760 based voice recorder and playback module can easily be controlled using any microcontroller like PIC, Arduino, etc. via SPI communication protocol.

ISD1760-Microcontroller Interfacing Diagram