1. Document Information

1.1. Abstract

This user guide shows how to get started with the MAVID-3M EVK.

1.2. Document Convention

Icon Meaning Description
Note Provides information good to know
Caution Indicates situation that might result in loss of data or hardware damage

2. MAVID-3M EVK

Libre Wireless provides evaluation kits (EVK) for users to gain familiarity with our products and expedite their own design and development. User can connect to MAVID- 3M module through UART to configure the module.

MAVID-3M EVK is a development platform for Libre’s MAVID-3M module or solution. MAVID-3M is a unique voice, AI, IoT platform or module with Wi-Fi 2.4GHz, BLE 5.0, voice DSP (far field/near field detection, NR and AEC), application SoC and on-board RAM and Flash (4MB each).

MAVID-3M EVK is a sophisticated kit with UART, SPI, I2C and GPIOs peripherals pin out for developers to explore and implement their ideas in the area of AI, IoT and voice. This development kit comes with compilation tool chain, user guides, data sheet, API guides, Libre standard SDK with example applications for voice to device control (bulb control, appliances control, motor control, etc.), demo mobile App (Android and iOS) and support through FAQs. This makes the initial bring up and POC smoother for the developers.

2.1. MAVID-3M EVK Block Diagram

Figure 2.1: MAVID-3M EVK Block Diagram

2.2. MAVID-3M EVK Image

Figure 2.2: MAVID-3M EVK Image

2.3. What You Need

  • MAVID-3M EVK
  • 5V/2A power adapter
  • Laptop Windows 8 or above/Linux
  • Android or iOS mobile with Libre app
  • Wi-Fi Router
  • Remote
  • Earphone or speaker with in-built speaker
  • One Micro USB cable (+One optional)

2.4. Unboxing and Powering up MAVID-3M EVK

  • MAVID-3M EVK Box contains 3 boards, namely MAVID-3M, Interconnect Card and EVK Board.

    Figure 2.4-1: EVK Board Setup

  • Connect all the 3 boards as shown in the below image to form a complete EVK board setup. Please take care while connecting the boards, do not offset any pins while connecting all the 3 boards into each other. Any offset may cause the improper function of MAVID-3M EVK or the whole setup can get damaged.

    Figure 2.4-2: EVK Board Setup

  • Power ON the board by supplying 5V adapter into the micro-USB connector (Power). If supplying by some external methods, do not exceed more than 5.5V or else it may damage the whole setup.
  • Connect the micro-USB cable from laptop to USB-TTL connector provided in the box.
  • PC requirements:
  • Windows 8 or above
  • Linus/Ubuntu → Add the currently used Ubuntu OS version from software team.
  • Audio Jack: Connect 3.5 mm Audio connector cable to listen the audio outs from Codec. Use earphone or speaker with in-built amplifier.
  • Analog MIC: Connect Analog MICs to the MIC Connector when testing Analog MIC into the board, else the connector can be left empty.

2.4.1. Jumper Connections

1. In the EVK board

  • DVDD_IO can be of 1.8V and 3.3V. To make the connection, follow the following connection:
  • Short pin number 1 and 2 of J23 by a jumper to get DVDD_IO = 3.3V
  • Short pin number 2 and 3 of J23 by a jumper to get DVDD_IO = 1.8V

    Figure 2.4.1-1: J23 Connector

  • Acoustic Echo Cancellation (AEC) can be performed in two ways, one from MAVID-3M side and another from Codec side. To make AEC from Codec do the following jumper connections:
  • Short pin number 1 and 2 of J24 and short pin number 1 and 2 of J25 to get AEC Left and Right from Codec respectively.

    If AEC done from MAVID-3M side above jumper connection is not required.

  • For analog MIC connection only short pin number 2 and 3 of J24 and short pin number 2 and 3 of J25 to feed 2nd analog mic N & P to Codec respectively.

    Figure 2.4-1: EVK Board Setup

  • 2. In Interconnect card

    • Short pin number 2 and 3 of CON6 to drive I2S_TXD from MediaTek Short pin number 1 and 2 of CON6 to drive I2S_TXD from Knowles (Post Processed)

      Figure 2.4.1-3: CON6 Connector

    • Only in case of Analog MIC
    • Short pin number 1 and 2 of J18 to connect LRCLK for I2S Format of Analog MIC Data
    • Short pin number 1 and 2 of J17 to connect BCLK for I2S Format of Analog MIC Data
    • Short pin number 1 and 2 of J19 to connect I2S Format of Analog MIC Data into Knowles

2.4.2. SPI Debug connector J17

Connector Pin Signal
J17.1 1.8V
J17.2 SPI MOSI
J17.3 SPI MISO
J17.4 SPI CS
J17.5 SPI CLK
J17.6 GND

2.4.3. I2C and MIC Connector J11

Connector Pin Signal
J11.1 MIC VDD
J11.2 DM0 CLK
J11.3 DM0 DAT
J11.4 DM1 CLK
J11.5 DM1 DAT
J11.6 I2C SCL
J11.7 I2C SDA
J11.8 GND

2.4.4. UART Connector J5

Connector Pin Signal
J5.1 TX
J5.2 RX
J5.3 GND

2.4.5. Class D Amplifier Connector

Connector Pin Signal
J3.1 SPO_LP
J3.2 SPO_LN
J3.3 SPO_RN
J3.4 SPO_RP

2.5. MAVID-3M Module

  • A module consists of 2 RF friendly connection i.e., Wi-Fi & BT (BLE) supports 20MHz, 40MHz bandwidth in 2.4GHz band.
  • Contains 4MB NOR Flash memory for program storage.
  • Provides I2S MCLK of 12.288MHz.
  • Contains VOICE over DSP for POST PROCESSING of Filtered Audio data.
  • MAVID-3M pinouts are as below:
Pin No. Connection Current Assigned
1 3.3V 3.3V
2 3.3V 3.3V
3 GPIO4_B GPIO4_B
4 GND GND
5 GPIO0_B GPIO0_B
6 GPIO9_B GPIO9_B
7 GPIO10_B PWR_OFF
8 CHIP_EN CHIP_EN
9 GPIO13_B MIC_PWR_CTRL
10 GND GND
11 I2S_MCLK I2S_MCLK
12 PORTA_FS I2S_LRCK
13 PORTA_FS I2S_BCLK
14 PORTA_DI PORTA_RXD
15 GPIO1 I2S_TXD
16 GPIO0 I2S_RXD
17 PORTA_DO PORTA_TXD
18 GPIO14 SPI_MISO
19 GPIO16 SPI_CLK
20 GPIO17 SPI_CS
21 GPIO15 SPI_MOSI
22 PORTB_FS PTT/SETUP
23 PORTB_CLK MIC_PWR_ON/OFF
24 PORTB_DI CHG_STATUS
25 PORTB_DO PLAY/PAUSE
26 GPIO_0(CHL) GPIO_0(CHL)
27 GPIO_1(CHL) GPIO_1(CHL)
28 PORTC_DO PORTC_DO
29 PORTC_DI PORTC_DI
30 PORTC_CLK PORTC_CLK
31 PORTC_FS PORTC_FS
32 COMMB_2 DSP_UART_TX
33 COMMB_3 DSP_UART_RX
34 GND GND
35 COMMB_1 UART1_TX
36 COMMB_0 UART1_RX
37 GND GND
38 NC NC
39 1.8V 1.8V
40 VDD_IO VDD_IO
41 VDD_IO VDD_IO
42 GPIO1_B LED_RED
43 GPIO15_B LED_GREEN
44 GPIO18_B LED_BLUE
45 RTC_EINT RTC_EINT
46 GPIO14_B CODEC_RST
47 GPIO8_B GPIO8_B
48 BTVBAT BTVBAT
49 VRTC VRTC
50 GND GND
51 GPIO18 ADC1
52 GPIO5 I2C0_SCL
53 GPIO6 I2C1_SDA
54 GPIO19 DEBUG_UART_RX
55 GPIO20 DEBUG_UART_TX
56 GND GND

2.5.1. Buck Converter 5V to 3.3V and 1.8V

  • The board contains buck converters to convert 5V to 3.3V and 5V to 1.8V.
  • Switching frequency and Max current achievable are 1.4MHz and 2A respectively.
  • Limits input to 5.5V Max.

2.5.2. ALC CODEC

  • 2 Analog to Digital Converter with 94dBA SNR.
  • 2 Digital to Analog Converter with 100dBA SNR.
  • 3 Differential ended Analog MIC inputs.
  • 3 Analog Audio output paths i.e., 2 Differential Class D speaker, Headphone and Mono Output.
  • I2S channels with up to 16 bits of I2S data for MCLK 12.288MHZ.
  • I2C communication with address 0x38 (Write), 0x39 (Read).

2.5.3. D8 RGB LED

State LED Indication
Ready/Idle State No Indication
Listening Cyan
Thinking Cyan and Blue - Alternating
Speaking Cyan and Blue - Pulsing
Notification Arrives Yellow - Burst
Notification Queued Yellow - Slow Pulse
Microphones Mute Red solid
Firmware Update Solid Magenta
Booting up White - blink
Wi-Fi Connected & Alexa not Connected Green blinking
Wi-Fi setup mode Multiple colors

2.5.4. Digital MICs

  • MEMS microphone with 65Db (A) SNR with a low distortion of 2.9% at 115dB SPL and a flat frequency response between 20 – 20kHz.
  • Max Supply = 3.6V, Max Clk freq = 4.8MHz.

2.5.5. Buttons functionality

Switch# Short press Functionality Long press Functionality MAVID_3M PORT
SW3 PTT SETUP PORTB_FS
SW4 MUTE Reboot PORTB_CLK
SW5 Vol+ NA PORTB_DI
SW6 Vol- NA PORTB_DO
SW7 Play/Pause NA NA

2.5.6. IR Transmitter & Receiver

  • The IR Transmitter diode chip consist of 3 diodes which can be connected in series, parallel, series - parallel based on requirement.
  • Typical Forward voltage (Vf) = 1.35V for Forward Current (If) = 60mA. The diode can be worked for Vf = 4.8V and If = 3A provided Pulse width <= 100usec and Duty cycle <=1%.
  • The IR transmitter diode on conducting has a wavelength of 940nm with bandwidth of 65nm.
  • Viewing angle of IR Transmitter is up to 140°.
  • IR Receiver receive all the IR signals in range of 20kHz - 60kHz. Supply voltage typically, between 2.5V - 5.5V.
  • Transmission distance of IR Receiver is 1.8 m typical with the directivity of 45°.