Silicon Laboratories Thunderboard EFM8UB3 User Manual

UG308: Thunderboard EFM8UB3 User's
Guide

The Thunderboard EFM8UB3 is a low cost, small form factor de­velopment and evaluation platform for the EFM8™ Universal Bee
Microcontroller.

The Thunderboard contains an EFM8UB3 MCU together with an on-board SEGGER J­Link debugger for easy debugging through the USB Micro-B debugging connector. All of
the EFM8 I/Os are routed to breakout pads on the sides of the board making it easy to
expand on the board features and evaluate the EFM8 Universal Bee's features with cus­tom hardware.

TARGET DEVICE

• EFM8 Universal Bee Microcontroller
(EFM8UB31F40G-A-QFN24)

• Pipelined 8-bit C8051 core with 48 MHz
maximum operating frequency

• 40 kB flash memory and 3328 bytes RAM

• USB feature set

KIT FEATURES

• USB connectivity

• SEGGER J-Link on-board debugger

• Virtual COM port

• User RGB LED and pushbuttons

• 2.54 mm breakout pads to EFM8

• Flat flexible cable connector for external
Silicon Labs "postage-stamp" sized
boards

• Optional Mini-Simplicity connector for
Advanced Energy Monitoring using
external Silicon Labs debugger

SOFTWARE SUPPORT

• Simplicity Studio™

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Table of Contents

1. Introduction ................................3

1.1 Kit Contents ..............................3

1.2 Getting Started .............................3

1.3 Kit Hardware Layout............................3

2. Electrical Specifications ...........................4

2.1 Absolute Maximum Ratings .........................4

3. Hardware .................................5

3.1 Block Diagram..............................5

3.2 Power Supply ..............................6

3.2.1 Self-Powered Mode ..........................6

3.2.2 Bus-Powered Mode ..........................6

3.3 Universal Serial Bus ............................7

3.4 Push Buttons and RGB LED .........................7

3.5 On-board Debugger ............................8

3.6 EFM8 Reset ..............................8

3.7 Connectors ...............................9

3.7.1 Breakout Pads ...........................10

3.7.2 Mini Simplicity Connector ........................11

3.7.3 EFM8 USB Micro-B Connector ......................11

3.7.4 Debug USB Micro-B Connector ......................11

3.7.5 Flat Flexible Cable Connector ......................12

4. Debugging ............................... 13

4.1 On-board Debugger Considerations ......................13

4.2 Virtual COM Port .............................14

4.3 Mini Simplicity Connector ..........................14

5. Kit Configuration and Upgrades ....................... 15

5.1 Firmware Upgrades ............................15

6. Schematics, Assembly Drawings and BOM ................... 16

7. Kit Revision History and Errata ....................... 17

7.1 Revision History .............................17

7.2 Errata ................................17

8. Board Revision History and Errata ...................... 18

8.1 Revision History .............................18

8.2 Errata ................................18

9. Document Revision History ......................... 19

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30 mm

45 mm

USB Micro-B Debug Connector

- Virtual COM port

- Debug access

Breakout Pads

USB Micro-B Connector

- Connected to EFM8

Reset Button

Push Button 1

Push Button 0

Mini Simplicity

Connector

Power Source

Slide Switch

EFM8

Universal Bee 3

On-board USB

J-Link Debugger

Top view

Bottom view

Flat Flexible Cable

Connector

RGB LED

{

2.54 mm pitch

UG308: Thunderboard EFM8UB3 User's Guide

Introduction

1. Introduction

The Thunderboard EFM8UB3 (OPN: SLTB005A) is an excellent starting point to get familiar with the EFM8 Universal Bee Microcontrol­lers. The Thunderboard contains an EFM8UB3 MCU together with an on-board SEGGER J-Link debugger for easy programming and
debugging through the USB Micro-B debug connector. The debugger also provides a USB virtual COM port for serial connection to the
target application.

All of the EFM8 I/Os are routed to breakout pads on the sides of the board making it easy to expand on the board features and evaluate
the EFM8 Universal Bee's features with custom hardware.

1.1 Kit Contents

The following items are included in the box:

• 1x Thunderboard EFM8UB3 board (BRD5002A)

• 1x Micro USB 2.0 to USB A male cable

1.2 Getting Started

Detailed instructions for how to get started with your new Thunderboard EFM8UB3 can be found on the Silicon Labs web pages:

http://www.silabs.com/start-efm8

1.3 Kit Hardware Layout

The layout of the Thunderboard EFM8UB3 is shown below.

Figure 1.1. Thunderboard EFM8UB3 Hardware Layout

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UG308: Thunderboard EFM8UB3 User's Guide

Electrical Specifications

2. Electrical Specifications

2.1 Absolute Maximum Ratings

Parameter Condition Min Typ Max Unit

Input voltage on EFM8 USB connector -0.3 - +5.8 V

Input voltage on debug USB connector 0 - +5.5 V

Output current Power-Source switch = EFM8 USB - - 100 mA

Power-Source switch = DBG USB - - 300 mA

Voltage on any breakout pad (excluding
P0.4, P0.5, P2.0 and RST)

Voltage on P0.4, P0.5, P2.0 and RST
breakout pad

1

VMCU > 3.3 V -0.3 - 5.8 V

VMCU < 3.3 V -0.3 - VMCU + 2.5 V

-0.3 - VMCU + 0.3 V

Current per EFM8 I/O pin -100 - 100 mA

Total current for all EFM8 I/O pins -400 - 400 mA

1 Limited by the debugger.

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3. Hardware

Mini-Simplicity

Connector

(Not mounted)

EFM8UB3

Microcontroller

USB Micro-B

Connector

J-Link

Debugger

USB Micro-B

Connector

Power Source

Switch

Power

User Buttons

& RGB LED

Breakout Pads

(EXP-Header pinout)

Flat Flexible

Cable Connector

DBG USB VBUS

EFM8 USB VBUS

C2 Debug
Virtual COM

USB

3.1 Block Diagram

An overview of the Thunderboard EFM8UB3 is illustrated in the figure below.

UG308: Thunderboard EFM8UB3 User's Guide

Hardware

Figure 3.1. Kit Block Diagram

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LDO

VDDVREGIN

EFM8 USB

VBUS

VMCU

DBG USB

LDO

5V

3V3

Power Source

DBG

USB

LDO

VDDVREGIN

VBUS

EFM8UB3

Isolated from VMCU

LDO

VDDVREGIN

EFM8 USB

VBUS

VMCU

DBG USB

LDO

5V

3V3

Power Source

EFM8
USB

EFM8UB3

UG308: Thunderboard EFM8UB3 User's Guide

Hardware

3.2 Power Supply

The EFM8 on the kit can be bus-powered, using its internal 5V-to-3.3 V regulator to provide power to itself and the VMCU net, or the
EFM8 can be self-powered with its internal regulator disabled. In self-powered mode, the EFM8 and the VMCU net are powered by an
on-board low-dropout regulator. Configuring the kit is done using the slide switch marked "Power Source" located in the lower right
corner of the board.

3.2.1 Self-Powered Mode

When the "Power Source" slide switch is in the "DBG USB" position, the EFM8 is connected in self-powered mode with its internal
regulator disabled. In this configuration, the EFM8 and the VMCU net are powered by an on-board regulator, which draws power from
the USB Micro-B debugging connector. The low-dropout regulator has a total output current capacity of 300 mA, in which some is being
used to power the on-board debugger through the 3V3 net.

Figure 3.2. Self-powered Mode

3.2.2 Bus-Powered Mode

When the "Power Source" slide switch is in the "EFM8 USB" position, the EFM8 is connected in bus-powered mode. In this configura­tion, the EFM8 and the VMCU net are powered by the EFM8UB3's internal 5V-to-3.3 V regulator. The input of the internal regulator
(VREGIN) is connected to the VBUS line of the USB Micro-B connector that is connected to the EFM8's USB peripheral.

Figure 3.3. Bus-powered Mode

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