MDK Overview


The Reference Moto Mod is the central component for the creation of your prototypes. It provides the core interfaces to the Moto Z platform, processing resources, GPIO and standard peripheral interfaces, power and charging control, and the capability to configure these blocks appropriately for your project.


Download Schematics

We provide schematics for the Moto Mods Development Kit. See the Downloads section at the end of this page for more.

Key Components and Configuration

The Moto Mod Micro Controller (MuC)

The MuC is the target for custom firmware for your Moto Mod. Powered by a Cortex-M4 based STML476, it provides onboard compute and control, GPIO, and various standard interfaces used to realize your project. The MuC is the main point of communication between the Moto Z and includes Greybus abstraction layer.

For further documentation on the STML476 used in the Reference Moto Mod:
ST Micro website for the STM32L476 
STM32L476XX Datasheet (Part Overview) 
STML4X6 Reference Manual (in depth technical detail) 

Moto High-Speed Bridge (MHB)

Industry standard CSI and DSI interfaces are supplied through the Moto Bridge as well as I2S audio for those Moto Mods requiring the camera or display interfaces.

Power and charging block

Contains the control, regulated and unregulated power control, battery selection, and charging paths for the Moto Mod system. See the DIP Switch B configuration section for the configuration options for this block.

USB Connectors

This set of three connectors enable connection of USB 2.0, MyDP and USB 3.1 peripherals, as well as Reference Moto Mod debug interfaces. Control and configuration of these connections is managed by the DIP switches.

Debug Connector (USB #1)

This Type C Connector is the debug port for all your projects using the Reference Moto Mod. The interfaces provided are detailed below.

  • Port 1 - MuC Serial Wire Debug (SWD)
  • Port 2 - MHB JTAG
  • Port 3 - MuC Serial Console
  • Port 4 - MHB Serial Console (Rx only)

The Moto Mod will accept 500mA of current into USB Connector 1 to power the Reference Moto Mod. USB Connector 1 will not charge the onboard battery or any battery included on your custom personality card.

USB Type-C Connector (USB #2)

This Type C Connector provides access to the following Mod interfaces:

  • USB 3.1 - host and slave
  • USB 2.0 - host only

The onboard battery on the Reference Moto Mod can be charged via this port. The port is compliant with USB C DRP.

MyDP connector (USB #3)

This Micro B connector provides access to the following Mod interfaces:

  • USB 2.0 - host only
  • MyDP

The Reference Moto Mod provides DC power out of the MyDP connector for USB Host mode support.

DIP Switch Configuration

Two DIP switches are provided to configure the Reference Moto Mod to support your Moto Mod project development.

DIP Switch A:

  • These switches control routing and selection of High Speed Signal Groups A and B.
  • Group A signals are defined as USB 2.0 and MyDP and are controlled by switches A3 and A4.
  • Group B signals include M-PHY, USB 3.1 and I2S functionality and are controlled by switches A1 and A2.
A1/A2 High speed Group B Control:
Device Type A1 A2 Description
Group B Disabled Off Off All Group B signal paths disabled.
MHB Device On Off Enables the Moto High-speed Bridge (MHB). Use this mode for devices requiring CSI or DSI on the 80-pin connector. When configured in this mode, I2S signals on the 80 pin connector are routed to the MHB as well. Used in the Display Personality Card example.
I2S Audio Device Off On Use for devices requiring direct access to I2S from the Moto Z. MHB is disabled and I2S signals on the 80-pin connector are routed to the Moto Mod connection to the Moto Z. Used in the Audio Personality Card example.
USB3.1 Device On On Use for devices requiring a USB3.1 host or client connection. MHB is disabled and USB3.1 is available on USB Type-C Connector.
A3/A4 High speed Group A Control:
Device Type A3 A4 Description
Group A Disabled Off Off All Group A signal paths disabled.
MyDP Device On Off Group A connected to MyDP Connector. Use to connect a MyDP device to the MyDP connector. This mode can also support USB Client devices connected to the MyDP port. In this mode power is available from the Reverence Moto Mod on the VBUS pin.
USB 2.0 Client Off On Group A connected to USB Type-C connector. Use to connect a USB Client device on the USB Type-C connector.
USB2.0 Personality Card On On Group A signals are routed to the 80-pin connector.

Dip Switch B:

These switches enable the reference clock for the Personality Card, control various power and charging configurations, and select GPIO or I2S functionality to the I2S signal group of the 80-pin connector.

Switch B1 - Personality Card Reference Clock Control:
Device Type B1 Description
Personality Card with onboard reference clock or none required Off 19.2 MHz clock disabled, pin 36 of 80-pin connector is high impedance
Personality Card requiring 19.2 MHz reference clock On 19.2 MHz clock enabled, present at pin 36 of 80-pin connector
Switch B2 - I2S Signal Group Alternate Mode:
Device Type B2 Description
I2S on 80-pin connector Off Use this mode if using I2S
GPIO alternate mode On Use this mode to use the pins as GPIO from the MuC (Notes 1,2)

Note 1: This mode disables the external 32kHz clock of the MuC.
Note 2: This mode disables the State of Charge LED functionality. (See On Board LEDs below).

Switch B3 - Battery Selection:
Device Type B3 Description
Reference Mod Battery Off Use this configuration if your project uses the battery provided on the Reference Moto Mod. In this mode, pin 17 of the 80-pin connector is disabled from providing power to the system.
Personality card Battery On Use this configuration if your personality card includes a battery. Charging and Metering is the responsibility of the Personality Card. In this mode, battery power for the Reference Moto Mod is derived from the 80-pin connector pin 17.
Switch B4 - USB-C Power Source:
Device Type B4 Description
USB Connector 2 Powered Off Use this mode to power the Reference Moto Mod from USB Type-C. Charging of onboard battery available (See Switch B3 above).
Debug connector Powered On Use this mode to power the Reference Moto Mod from the Debug Connector
Note: This mode will not charge any battery (on-board or Personality Card)

Example Personality Card Configurations

The table below details the DIP switch configuration for each of the available example Personality Cards.

Example Personality Card Configurations:
Personality Card DIP Switch A DIP Switch B
A1 A2 A3 A4 B1 B2 B3 B4
DSI Display On Off X X X X Off X
Audio Off On X X X Off Off X
Battery X X X X X X On X
Sensor X X X X X X Off X

Note: X = Not Applicable

Onboard LEDs

The Reference Moto Mod contains three LEDs. Two LEDs are used to indicate the Reference Moto Mod battery state of charge, and the other is available for you to use in your applications.

LED Connection and Active State:

LED GPIO State Usage
Red LED (Bottom) PD7 Low: LED On
High: LED off
Indicates Battery State of Charge (SoC) in conjunction with the Green LED
Green LED (Bottom) PE7 Low: LED On
High: LED off
Indicates Battery SoC in conjunction with the Red LED
White LED (Top) PE8 Low: LED On
High: LED off
User defined



Personality Board Connector

Personality cards attach to the 80-pin connector. This connector provides access to GPIO, power, and multiple standard busses. The function of some pins is controlled by the DIP switches.

Connector Definition

The 80-pin connector exposes various Moto Mod interfaces to make it easy for you to develop and switch between projects using a single Reference Moto Mod.


Pin Signal Name Signal Type Primary Function Alternate Function
(see note 6)
Interrupt Group
(see note 7)
1 3P3 Power Regulated 3.3-volt, 500mA power source (see note 1)    
2 PC1 MuC GPIO I2C3_SDA (see note 2)    
3 HSIC_STB MHB HSIC HSIC Strobe. For details, see USB-Ext firmware document    
4 PC0 MuC GPIO I2C3_SCL (see note 2)    
5 HSIC_DAT MHB HSIC HSIC data. For details, see USB-Ext firmware document    
6 PB2 MuC GPIO General-purpose input/output MuC_TIMER1_OUT,
7 GND Ground System ground    
8 PA2 MuC GPIO General-purpose input/output MuC_UART2 TX  
9 5P0 Power Regulated 5-volt, 1.5A power source (see note 1)    
10 PA3 MuC GPIO General-purpose input/output MuC_UART2 RX,
MuC_Interrupt_IN (see note 7)
Group 3
11 VBUS Power VBUS power input/output from/to Moto Mod    
12 PA0 MuC GPIO General-purpose input/output MuC_UART2 CTS,
13 1P8 Power Regulated 1.8-volt, 1A power source (see note 1)    
14 PA1 MuC GPIO General-purpose input/output MuC_UART2 RTS,
15 GND Ground System ground    
16 PA10 MuC GPIO General-purpose input/output MuC_Interrupt_IN (see note 7) Group 10
17 VSYS Power System DC power from Personality Card    
18 PC8 MuC GPIO General-purpose input/output    
19 B+ Power System DC power from Moto Mod    
20 PA7 MuC GPIO General-purpose input/output MuC_SPI1_MOSI,
MuC_Interrupt_IN (see note 7)
Group 7
21 GND Ground System ground    
22 PA6 MuC GPIO General-purpose input/output MuC_SPI1_MISO,
MuC_Interrupt_IN (see note 7)
Group 6
23 PC7 MuC GPIO General-purpose input/output MuC_Interrupt_In (see note 7) Group 7
24 PD6 MuC GPIO General-purpose input/output MuC_UART2 RX,
MuC_Interrupt_IN (see note 7)
Group 6
25 PC14 MuC GPIO General-purpose input/output Master_I2S_BCLK (see note 3)  
26 PA5 MuC GPIO General-purpose input/output MuC_SPI1_SCK  
27 PC15 MuC GPIO General-purpose input/output Master_I2S_WS (see note 3)  
28 PA4 MuC GPIO General-purpose input/output MuC_SPI1_CS0  
29 PE7 MuC GPIO General-purpose input/output Master_I2S_SDI (see note 3)  
30 PA15 MuC GPIO General-purpose input/output MuC_SPI1_CS1,
MuC_Interrupt_IN (see note 7)
Group 15
31 PD7 MuC GPIO General-purpose input/output Master_I2S_SDO (see note 3)  
32 PA9 MuC GPIO General-purpose input/output    
33 PC9 MuC GPIO General-purpose input/output    
34 GND Ground System ground    
35 TE Input Tearing Effect (Display Sync) input from personality card    
36 19P2 Output 19.2 MHz CMOS clock output to personality card (see note 4)    
37 GND Ground System ground    
38 GND Ground System ground    
39 DSI_D0- Display MIPI DSI_D0- output/input to/from personality card    
40 DSI_D2- Display MIPI DSI_D2- output to personality card    
41 DSI_D0+ Display MIPI DSI_D0+ output/input to/from personality card    
42 DSI_D2+ Display MIPI DSI_D2+ output to personality card    
43 GND Ground System ground    
44 GND Ground System ground    
45 DSI_D1- Display MIPI DSI_D1- output to personality card    
46 DSI_D3- Display MIPI DSI_D3- output to personality card    
47 DSI_D1+ Display MIPI DSI_D1+ output to personality card    
48 DSI_D3+ Display MIPI DSI_D3+ output to personality card    
49 GND Ground System ground    
50 GND Ground System ground    
51 DSI_CLK- Display MIPI DSI_C- output to personality card    
52 MUC_PB11 MuC GPIO General-purpose input/output MuC_I2C2_SDA (see note 2)  
53 DSI_CLK+ Display MIPI DSI_C+ output to personality card    
54 PB10 MuC GPIO General-purpose input/output MuC_I2C2 SCL (see note 2), MuC_Interrupt_IN (see note 7) Group 10
55 GND Ground System ground    
56 GND Ground System ground    
57 CSI_D0- Camera MIPI CSI_D0- input from personality card    
58 CSI_D2- Camera MIPI CSI_D2- input from personality card    
59 CSI_D0+ Camera MIPI CSI_D0+ input from personality card    
60 CSI_D2+ Camera MIPI CSI_D2+ input from personality card    
61 GND Ground System ground    
62 GND Ground System ground    
63 CSI_D1- Camera MIPI CSI_D1- input from personality card    
64 CSI_D3- Camera MIPI CSI_D3- input from personality card    
65 CSI_D1+ Camera MIPI CSI_D1+ input from personality card    
66 CSI_D3+ Camera MIPI CSI_D3+ input from personality card    
67 GND Ground System ground    
68 GND Ground System ground    
69 CSI_CLK- Camera MIPI CSI_C- input from personality card    
70 PH0 MuC GPIO General-purpose input/output    
71 CSI_CLK+ Camera MIPI CSI_C+ input from personality card    
72 PC3 MuC GPIO General-purpose input/output MuC_ADC_IN4,
MuC_Interrupt_IN (see note 7)
Group 3
73 GND Ground System ground    
74 PC12 MuC GPIO General-purpose input/output    
75 USB_D+ USB USB data positive (see note 5)    
76 PG9 MuC GPIO General-purpose input/output    
77 USB_D- USB USB data negative (see note 5)    
78 PG10 MuC GPIO General-purpose input/output MuC_TIMER1_IN1, MuC_Interrupt_IN (see note 7) Group 10
79 GND Ground System ground    
80 PG12 MuC GPIO General-purpose input/output    


  • (1) Regulator current limit assumes source selected by DIP Switch B3 provides sufficient DC power for your application.
  • (2) All MuC GPIO referenced to 1.8V.
  • (3) I2S present only if DIP switches A1 and A2 set to enable I2S audio device type.
  • (4) 19.2 MHz clock present DIP switch B1 set to “on” position.
  • (5) USB signals present only if DIP switches A3 and A4 set to direct these signals to the personality card.
  • (6) Alternate function enabler please refer to firmware document.
  • (7) Only one Interrupt function allow within same group.

Using Example Personality Cards

Inserting and Removing Personality Card

ALWAYS detach the Reference Moto Mod from Moto Z before attempting to insert or remove a Personality Card, the Perforated Board, or Raspberry Pi HAT Adapter Board.

Inserting Personality Card Into Reference Moto Mod

  • Step 1: Toe-in top edge of board under housing tabs
  • Step 2: Press board down to seat the connector


Removing Personality Card From Reference Moto Mod

  • Step 1: Grip sides of board within two finger scoops
  • Step 2: Pull up to unseat the 80-pin connector


Installation of Custom Firmware

The example Personality Cards require custom firmware on the Reference Moto Mod to run. Each Personality Card includes an onboard EEPROM queried by the MuC bootloader on attach. If needed, the MuC bootloader will request the Moto Z to download and install the latest firmware needed for the attached personality card.

When using the Perforated Board, or Pi HAT Adapter Board, don’t forget to create a custom bootloader for your MuC that includes your unique VID/PID, or the prototype VID 0x42. If you don’t you’ll end up overwriting your custom firmware with the default MuC firmware each time you boot!


This section contains the downloadable files associated with this example.

All Downloads

Safety Instructions


  • Important: This product contains magnets. Always keep products with magnets more than 20 cm. (8 in.) from medical devices, such as pacemakers, internal cardio defibrillators or other devices that can be affected by a magnetic field. Also, keep products with magnets away from credit cards, ID cards, and other media that use magnetically encoded information.
  • Due to the nature of the product, it is not possible to fully meet ESD (Electrostatic Discharge) Protection requirements as components and interconnections are more exposed in a development kit. Should the audio/video stop unexpectedly, remove and re-attach the Personality Card.
  • The reference Moto Mod shall only be powered by connecting it to a Moto Z device or through the USB Connectors 1 & 2.
  • A Personality Card shall only be powered by inserting it into the Reference Moto Mod.
  • Always detach the Reference Moto Mod from Moto Z before attempting to insert or remove a Personality Card, the Perforated Board, or Raspberry Pi HAT Adapter Board.
  • This product should be operated in a well ventilated environment.
  • This product should be placed on a stable, flat, non-conductive surface in use and should not be contacted by conductive items.
  • The connection of incompatible devices to the GPIO connector may affect compliance or result in damage to the unit and invalidate the connected Moto Z’s warranty
  • All peripherals used with the Moto Mods Development Kit should comply with relevant standards for the country of use and be marked accordingly to ensure that safety and performance requirements are met.
  • If peripherals are connected via a cable or connector, the cable or connector used must offer adequate insulation and operation in order that the requirements of the relevant performance and safety requirements are met.
  • Any damage to your Moto Z’s caused by the use of the Moto Mods Development kit is not covered by the Moto Z limited warranty.
  • Motorola accepts no liability arising from the use or misuse of the MDK or Moto Mods platform, or any applications based upon it
  • Apps and MDK projects must only be built by someone competent to do so.

Instructions for safe use

To avoid malfunction or damage to your MDK or Moto Z please observe the following:

  • Always use industry standard practices for handling and developing electronic devices.
  • Do not expose it to water, moisture or place on a conductive surface whilst in operation.
  • Do not expose it to heat from any source; the MDK is designed for reliable operation at normal ambient room temperatures.
  • Take care whilst handling to avoid mechanical or electrical damage to the printed circuit board and connectors.
  • Avoid handling the printed circuit board while it is powered. Only handle by the edges to minimise the risk of electrostatic discharge damage.
  • Where a protective cover is provided, it is recommended that it is used to provide mechanical and electrical protection to the components.
  • Take care of sharp edges and connector pins.

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