System Reference Manual

Jason Kridner edited this page Jul 5, 2018 · 115 revisions

PocketBeagle

System Reference Manual (SRM)

Revision A.x (on-line wiki edition)

December 6, 2017

Maintaining author: Jason Kridner jkridner@beagleboard.org

Contributing Editor: Cathy Wicks cathy@beagleboard.org

THIS DOCUMENT

Terms These design materials are *NOT SUPPORTED* and *DO NOT* constitute a reference design. Only “community” support is allowed via resources at BeagleBoard.org/discuss.

THERE IS NO WARRANTY FOR THE DESIGN MATERIALS, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE DESIGN MATERIALS “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE DESIGN MATERIALS IS WITH YOU. SHOULD THE DESIGN MATERIALS PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

In other words, you may use the design materials as you choose and there is no license with regards to usage in the manufacturing process. We mean it, these design materials may be totally unsuitable for any purposes. Don't blame us!

As a general rule, we don't encourage use of this or other off-the-shelf single board computers in commercial products without engaging with a manufacturer to create a supplier agreement and make sure that you can get material as your business demands. Further, we do update the design on occasions where we find it necessary and won't guarantee a supply of older revisions, though we do seek periodic manufacturing of all of our boards for a period of roughly 10 years and will make design changes to replace obsolete parts and that may impact your usage. If you do opt to use it in a product, you take full responsibility for that product.

Do not use the BeagleBoard.org logo or trademarks (such as BeagleBoard, BeagleBone and PocketBeagle) on your products without a logo license from the BeagleBoard.org Foundation, but feel free to reference BeagleBoard.org.

See the LICENSE file regarding the copyright of these materials.

Table of Contents

1.0 Introduction

This document is the System Reference Manual for PocketBeagle and covers its use and design. PocketBeagle is an ultra-tiny-yet-complete Linux-enabled, community-supported, open-source USB-key-fob-computer. PocketBeagle features an incredible low cost, slick design and simple usage, making it the ideal development board for beginners and professionals alike. Simply develop directly in a web browser providing you with a playground for programming and electronics. Exploring is made easy with several available libraries and tutorials with many more coming.

PocketBeagle will boot directly from a microSD card. Load a Linux distribution onto your card, plug your board into your computer and get started. PocketBeagle runs GNU.Linux, so you can leverage many different high-level programming languages and a large body of drivers that prevent you from needing to write a lot of your own software.

This design will keep improving as the product matures based on feedback and experience. Software updates will be frequent and will be independent of the hardware revisions and as such not result in a change in the revision number of the board. A great place to find out the latest news and projects for PocketBeagle is on the home page beagleboard.org/pocket

Figure 1. PocketBeagle Home Page

Make sure you check the support Wiki frequently for the most up to date information. github.com/beagleboard/pocketbeagle/wiki

2.0 Change History

This section describes the change history of this document and board. Document changes are not always a result of a board change. A board change will always result in a document change.

2.1 Document Change History

Table 1. Change History
Rev Changes Date By
A.x Production Document December 7, 2017 JK

2.2 Board Changes

Table 2. Board History
Rev Changes Date By
A1 Preliminary February 14, 2017 JK
A2 Production. Fixed mikroBUS Click reset pins (made GPIO). September 22, 2017 JK

2.2.1 PocketBone

Upon the creation of the first, 27mm-by-27mm, Octavo Systems OSD3358 SIP, Jason did a hack two-layer board in EAGLE called “PocketBone” to drop the Beagle name as this was a totally unofficial effort not geared at being a BeagleBoard.org Foundation project. The board never worked because the 32kHz and 24MHz crystals were backwards and Michael Welling decided to pick it up and redo the design in KiCad as a four-layer board. Jason paid for some prototypes and this resulted in the first successful “PocketBone”, a fully-open-source 1-GHz Linux computer in a fitting into a mini-mint tin.

2.2.2 Rev A1

The Rev A1 of PocketBeagle was a prototype not released to production. A few lines were wrong to be able to control mikroBUS Click add-on board reset lines and they were adjusted.

2.2.3 Rev A2

The Rev A2 of PocketBeagle was released to production and at World MakerFaire 2017.

Known issues in rev A2:

Issue Link
GPIO44 is incorrectly labelled as GPIO48 github.com/beagleboard/pocketbeagle/issues/4

3.0 Connecting Up PocketBeagle

This section provides instructions on how to hook up your board. The most common scenario is tethering PocketBeagle to your PC for local development.

3.1 What’s In the Package

In the package you will find two items as shown in Figures 2 and 3.

  • PocketBeagle
  • Getting Started instruction card with link to the support URL.
Figure 2. PocketBeagle Package

Figure 3. PocketBeagle Package Insert

3.2 Connecting the board

This section will describe how to connect to the board. Information can also be found on the Quick Start Guide that came in the box. Detailed information is also available at beagleboard.org/getting-started

The board can be configured in several different ways, but we will discuss the most common scenario. Future revisions of this document may include additional configurations.

3.3 Tethered to a PC using Debian Images

In this configuration, you will need the following additional items:

  • microUSB to USB Type A Cable
  • microSD card (>=4GB and <128GB)
The board is powered by the PC via the USB cable, no other cables are required. The board is accessed either as a USB storage drive or via a web browser on the PC. You need to use either Firefox or Chrome on the PC, IE will not work properly. Figure 4 shows this configuration.
Figure 4. Tethered Configuration

In some instances, such as when additional add-on boards, or PocketCapes are connected, the PC may not be able to supply sufficient power for the full system. In that case, review the power requirements for the add-on board/cape; additional power may need to be supplied via the 5v input, but rarely is this the case.

3.3.1 Getting Started

The following steps will guide you to quickly download a PocketBeagle software image onto your microSD card and get started writing code.

1. Navigate to the Getting Started Page beagleboard.org/getting-started Follow along with the instructions and click on the link noted in Figure 5 below beagleboard.org/latest-images. You can also get to this page directly by going to bbb.io/latest

Figure 5. Getting Started Page

2. Download the latest image onto your computer by following the link to the latest image and click on the Debian image for Stretch IoT (non-GUI) for BeagleBone and PocketBeagle via microSD card. See Figure 6 below. This will download a .img.xz file into the downloads folder of your computer.

Figure 6. Download Latest Software Image

3. Transfer the image to a microSD card.

Download and install an SD card programming utility if you do not already have one. We like https://etcher.io/ for new users and so we show that one in the steps below. Go to your downloads folder and doubleclick on the .exe file and follow the on-screen prompts. See figure 7.

Figure 7. Download Etcher SD Card Utility



Insert a new microSD card into a card reader/writer and attach it via the USB connection to your computer. Follow the instructions on the screen for selecting the .img file and burning the image from your computer to the microSD card. Eject the SD card reader when prompted and remove the card. See Figures 8 and 9.

Figure 8. Select the PocketBeagle Image

Figure 9. Burn the Image to the SD Card

4. Insert the microSD card into the board - you'll hear a satisfying click when it seats properly into the slot. It is important that your microSD card is fully inserted prior to powering the system.

Figure 10. Insert the microSD Card into PocketBeagle

5. Connect the micro USB connector on your cable to the board as shown in Figure 11. The microUSB connector is fairly robust, but we suggest that you not use the cable as a leash for your PocketBeagle. Take proper care not to put too much stress on the connector or cable.

Figure 11. Insert the micro USB Connector into PocketBeagle

6. Connect the large connector of the USB cable to your Linux, Mac or Windows PC USB port as shown in Figure 12. The board will power on and the power LED will be on as shown in Figure 13 below.

Figure 12. Insert the USB connector into PC

Figure 13. Board Power LED

7. As soon as you apply power, the board will begin the booting process and the userLEDs Figure 14 will come on in sequence as shown below. It will take a few seconds for the status LEDs to come on, like teaching PocketBeagle to 'stay'. The LEDs will be flashing as it begins to boot the Linux kernel. While the four user LEDS can be over written and used as desired, they do have specific meanings in the image that you've initially placed on your microSD card once the Linux kernel has booted.

  • USER0 is the heartbeat indicator from the Linux kernel.
  • USER1 turns on when the microSD card is being accessed
  • USER2 is an activity indicator. It turns on when the kernel is not in the idle loop.
  • USER3 idle
Figure 14. User LEDs

3.3.2 Accessing the Board and Getting Started with Coding

The board will appear as a USB Storage drive on your PC after the kernel has booted, which will take approximately 10 seconds. The kernel on the board needs to boot before the port gets enumerated. Once the board appears as a storage drive, do the following:

1. Open the USB Drive folder to view the files on your PocketBeagle.

2. Launch Interactive Quick Start Guide.

Right Click on the file named START.HTM and open it in Chrome or Firefox. This will use your browser to open a file running on PocketBeagle via the microSD card. You will see file:///Volumes/BEAGLEBONE/START.htm in the url bar of the browser. See Figure 15 below. This action displays an interactive Quick Start Guide from PocketBeagle.

Figure 15. Interactive Quick Start Guide Launch

3. Enable a Network Connection.

Click on 'Step 2' of the Interactive Quick Start Guide page to follow instructions to "Enable a Network Connection" (pointing to the DHCP server that is running on PocketBeagle). Copy the appropriate IP Address from the chart (according to your PC operating system type) and paste into your browser then add a :3000 to the end of it. See example in Figure 16 below. This will launch from PocketBeagle one of it's favorite Web Based Development Environments, Cloud9 IDE, (Figure 17) so that you can teach your beagle new tricks!

Figure 16. Enable a Network Connection

Figure 17. Launch Cloud9 IDE

4. Get Started Coding with Cloud9 IDE - blinking USR3 LED in JavaScript using the BoneScript library example

  1. Create a new text file
  2. Copy and paste the below code into the editor
    var b = require('bonescript');
    var state = b.LOW;
    b.pinMode("USR3", b.OUTPUT);
    setInterval(toggle, 250);  // toggle 4 times a second, every 250ms
    function toggle() {
        if(state == b.LOW) state = b.HIGH;
        else state = b.LOW;
        b.digitalWrite("USR3", state);
    }
    
  3. Save the new text file as blinkusr3.js within the default directory
  4. Execute
    node blinkusr3.js
    within the default (/var/lib/cloud9) directory
  5. Type CTRL+C to stop the program running

3.3.3 Powering Down

1. Standard Power Down Press the power button momentarily with a tap. The system will power down automatically. This will shut down your software with grace. Software routines will run to completion.

The Standard Power Down can also be invoked from the Linux command shell via "sudo shutdown -h now".

2. Hard Power Down Press the power button for 10 seconds. This will force an immediate shut down of the software. For example you may lose any items you have written to the memory. Holding the button longer than 10 seconds will perform a power reset and the system will power back on.

3. Remove the USB cable Remember to hold your board firmly at the USB connection while you remove the cable to prevent damage to the USB connector.

4. Powering up again. If you'd like to power up again without removing the USB cable follow these instructions:

  1. If you used Step 1 above to power down, to power back up, hold the power button for 10 seconds, release then tap it once and the system will boot normally.
  2. If you used Step 2 above to power down, to power back up, simply tap the power button and the system will boot normally.
Figure 20. Power Button

3.4 Other ways to Connect up to your PocketBeagle

The board can be configured in several different ways. Future revisions of this document may include additional configurations.

As other examples become documented, we'll update them on the Wiki for PocketBeagle github.com/beagleboard/pocketbeagle/wiki See also the on-line discussion.

4.0 PocketBeagle Overview

PocketBeagle is built around Octavo Systems' OSD335x-SM System-In-Package that integrates a high-performance Texas Instruments AM3358 processor, 512MB of DDR3, power management, nonvolatile serial memory and over 100 passive components into a single package. This integration saves board space by eliminating several packages that would otherwise need to be placed on the board, but more notably simplifies our board design so we can focus on the user experience.

The compact PocketBeagle design also offers access through the expansion headers to many of the interfaces and allows for the use of add-on boards called PocketCapes and Click Boards from MikroElektronika, to add many different combinations of features. A user may also develop their own board or add their own circuitry.

4.1 PocketBeagle Features and Specification

This section covers the specifications and features of the board in a chart and provides a high level description of the major components and interfaces that make up the board.

Table 3. PocketBeagle Features
Feature '
System-In-Package Octavo Systems OSD335x-SM in 256 Ball BGA (21mm x 21mm)
SiP Incorporates :
Processor Texas Instruments 1GHz Sitara™ AM3358 ARM® Cortex®-A8 with NEON floating-point accelerator
Graphics Engine Imagination Technologies PowerVR SGX530 Graphics Accelerator
Real-Time Units 2x programmable real-time unit (PRU) 32-bit 200MHz microcontrollers with single-cycle I/O latency
Coprocessor ARM® Cortex®-M3 for power management functions
SDRAM Memory 512MB DDR3 800MHz RAM
Non-Volatile Memory 4KB I2C EEPROM for board configuration information
Power Management TPS65217C PMIC along with TL5209 LDO to provide power to the system with integrated 1-cell LiPo battery support
Connectivity :
SD/MMC Bootable microSD card slot
USB High speed USB 2.0 OTG (host/client) micro-B connector
Debug Support JTAG test points and gdb/other monitor-mode debug possible
Power Source microUSB connector, also expansion header options (battery, VIN or USB-VIN)
User I/O Power Button with press detection interrupt via TPS65217C PMIC
Expansion Header :
USB High speed USB 2.0 OTG (host/client) control signals
Analog Inputs 8 analog inputs with 6 @ 1.8V and 2 @ 3.3V along with 1.8V references
Digital I/O 44 digital GPIOs accessible with 18 enabled by default including 2 shared with the 3.3V analog input pins
UART 3 UARTs accessible with 2 enabled by default
I2C 2 I2C busses enabled by default
SPI 2 SPI busses with single chip selects enabled by default
PWM 4 Pulse Width Modulation outputs accessible with 2 enabled by default
QEP 2 Quadrature encoder inputs accessible
CAN 2 CAN bus controllers accessible

4.1.1 OSD3358-512M-BSM System in Package

The Octavo Systems OSD3358-512M-BSM System-In-Package (SiP) is part of a family of products that are building blocks designed to allow easy and cost-effective implementation of systems based in Texas Instruments powerful Sitara AM335x line of processors. The OSD335x-SM integrates the AM335x along with the TI TPS65217C PMIC, the TI TL5209 LDO, up to 1 GB of DDR3 Memory, a 4 KB EEPROM for non-volatile configuration storage and resistors, capacitors and inductors into a single 21mm x 21mm design-in-ready package.

With this level of integration, the OSD335x-SM family of SiPs allows designers to focus on the key aspects of their system without spending time on the complicated high-speed design of the processor/DDR3 interface or the PMIC power distribution. It reduces size and complexity of design.

Full Datasheet and more information is available at octavosystems.com/octavo_products/osd335x-sm/

4.2 Board Component Locations

This section describes the key components on the board, their location and function.

Figure 21 below shows the locations of the devices, connectors, LEDs, and switches on the PCB layout of the board.

Figure 21. Key Board Component Locations

Key Components

  • The Octavo Systems OSD3358-512M-BSM System-In-Package is the processor system for the board
  • P1 and P2 Headers come unpopulated so a user may choose their orientation
  • User LEDs provides 4 programmable blue LEDs
  • Power BUTTON can we used to power up or power down the board (see section 3.3.3 for details)
  • USB 2.0 OTG is a microUSB connection to a PC that can also power the board
  • Power LED provides communication regarding the power to the board
  • microSD slot is where a microSD card can be installed.

5.0 PocketBeagle High Level Specification

This section provides the high level specification of PocketBeagle.

5.1 Block Diagram

Figure 22 below is the high level block diagram of PocketBeagle.

Figure 22. PocketBeagle Key Components

5.2 System in Package (SiP)

The OSD335x-SM Block Diagram is detailed in Figure 23 below. More information, including design resources are available on the 'Octavo Systems Website'

Figure 23. OSD335x SIP Block Diagram

Note: PocketBeagle utilizes the 512MB DDR3 memory size version of the OSD335x-SM A few of the features of the OSD335x-SM SiP may not be available on PocketBeagle headers. Please check Section 7 for the P1 and P2 header pin tables.

5.3 Connectivity

5.3.1 Expansion Headers

PocketBeagle gives access to a large number of peripheral functions and GPIO via 2 dual rail expansion headers. With 36 pins each, the headers have been left unpopulated to enable users to choose the header connector orientation or add-on board / cape connector style. Pins are clearly marked on the bottom of the board with additional pin configurations available through software settings. Detailed information is available in Section 7.

Figure 24. PocketBeagle Expansion Headers

5.3.2 microSD Connector

The board is equipped with a single microSD connector to act as the primary boot source for the board. Just about any microSD card you have will work, we commonly find 4G to be suitable.

When plugging in the SD card, the writing on the card should be up. Align the card with the connector and push to insert. Then release. There should be a click and the card will start to eject slightly, but it then should latch into the connector. To eject the card, push the SD card in and then remove your finger. The SD card will be ejected from the connector. Do not pull the SD card out or you could damage the connector.

Figure 25. microSD Connector

5.3.3 USB 2.0 Connector

The board has a microUSB connector that is USB 2.0 HS compatible that connects the USB0 port to the SiP. Generally this port is used as a client USB port connected to a power source, such as your PC, to power the board. If you would like to use this port in host mode you will need to supply power for peripherals via Header P1 pin 7 (USB1.VIN) or through a powered USB Hub. Additionally, in the USB host configuration, you will need to power the board through Header P1 pin 1 (VIN) or Header P1 pin 7 (USB1.VIN) or Header P2 pin 14 (BAT.VIN)

Figure 26. USB 2.0 Connector

5.3.4 Boot Modes

There are three boot modes:

  • SD Boot: MicroSD connector acts as the primary boot source for the board. This is described in Section 3.
  • USB Boot: This mode supports booting over the USB port. More information can be found in the project called "BeagleBoot" This project ported the BeagleBone bootloader server BBBlfs(currently written in c) to JavaScript(node.js) and make a cross platform GUI (using electron framework) flashing tool utilizing the etcher.io project. This will allow a single code base for a cross platform tool. For more information on BeagleBoot, see the BeagleBoot Project Page.
  • Serial Boot: This mode will use the serial port to allow downloading of the software. A separate USB to TTL level serial UART converter cable is required or you can connect one of the Mikroelektronika FTDI Click Boards to use this method. The UART pins on PocketBeagle's expansion headers support the interface. For more information regarding the pins on the expansion headers and various modes, see Section 7.
Table 4. UART Pins on Expansion Headers for Serial Boot
Header.Pin Silkscreen Proc Ball SiP Ball Pin Name (Mode 0)
P1.22 GND GND
P1.30 U0_TX E16 B12 uart0_txd
P1.32 U0_RX E15 A12 uart0_rxd

If the Serial Boot is not in use, the UART0 pins can be used for Serial Debug. See Section 5.6 for more information.

Software to support USB and serial boot modes is not provided by beagleboard.org. Please contact TI for support of this feature.

5.4 Power

The board can be powered from three different sources:

  • A USB port on a PC.
  • A power supply with a USB connector.
  • Expansion Header pins.
The tables below show the power related pins available on PocketBeagle's Expansion Headers.
Table 5. Power Inputs Available on Expansion Headers
Header.Pin Silkscreen Proc Ball SiP Ball Pin Name (Mode 0)
P1.01 VIN P10, R10, T10 VIN
P1.07 USB1_VI P9, R9, T9 VIN-USB
P2.14 BAT_+ P8, R8, T8 VIN-BAT
Table 6. Power Outputs Available on Expansion Headers
Header.Pin Silkscreen Proc Ball SiP Ball Pin Name (Mode 0)
P1.14 +3.3V F6, F7, G6, G7 VOUT-3.3V
P1.24 VOUT K6, K7, L6, L7 VOUT-5V
P2.13 VOUT K6, K7, L6, L7 VOUT-5V
P2.23 +3.3V F6, F7, G6, G7 VOUT-3.3V
Table 5. Ground Pins Available on Expansion Headers
Header.Pin Silkscreen Proc Ball SiP Ball Pin Name (Mode 0)
P1.15 USB1_GND GND
P1.16 GND GND
P1.22 GND GND
P2.15 GND GND
P2.21 GND GND

Note: A comprehensive tutorial for Power Inputs and Outputs for the OSD335x System in Package is available in the 'Tutorial Series' on the Octavo Systems website.

5.5 JTAG Pads

Pads for an optional connection to a JTAG emulator has been provided on the back of PocketBeagle. More information about JTAG emulation can be found on the TI website - 'Entry-level debug through full-capability development'

Figure 27. JTAG Pad Connections

5.6 Serial Debug Port

Serial debug is provided via UART0 on the processor. See Section 5.3.4 for the Header Pin table. Signals supported are TX and RX. None of the handshake signals (CTS/RTS) are supported. A separate USB to TTL level serial UART converter cable is required or you can connect one of the Mikroelektronika FTDI Click Boardsto use this method.

Figure 28. Serial Debug Connections

If serial boot is not used, the UART0 can be used to view boot messages during startup and can provide access to a console using a terminal access program like Putty. To view the boot messages or use the console the UART should be set to a baud rate of 115200 and use 8 bits for data, no parity bit and 1 stop bit (8N1).

6.0 Detailed Hardware Design

The following sections contain schematic references for PocketBeagle. Full schematics in both PDF and Eagle are available on the 'PocketBeagle Wiki'

6.1 OSD3358-SM SiP Design

Schematics for the OSD3358-SM SiP are divided into several diagrams.

6.1.1 SiP A OSD3358 SiP System and Power Signals

Figure 29. SiP A OSD3358 SiP System and Power Signals

6.1.2 SiP B OSD3358 SiP JTAG, USB & Analog Signals

Figure 30. SiP B OSD3358 SiP JTAG, USB & Analog Signals

6.1.3 SiP C OSD3358 SiP Peripheral Signals

Figure 31. SiP C OSD3358 SiP Peripheral Signals

6.1.4 SiP D OSD3358 SiP System Boot Configuration

Figure 32. SiP D OSD3358 SiP System Boot Configuration

6.1.5 SiP E OSD3358 SiP Power Signals

Figure 33. SiP E OSD3358 SiP Power Signals

6.1.6 SiP F OSD3358 SiP Power Signals

Figure 34. SiP F OSD3358 SiP Power Signals

6.2 MicroSD Connection

The Micro Secure Digital (microSD) connector design is highlighted in Figure 35.

Figure 35. microSD Connections

6.3 USB Connector

The USB connector design is highlighted in Figure 36.

Note that there is an ID pin for dual-role (host/client) functionality. The hardware fully supports it, but care should be taken to ensure the kernel in use is either statically or dynamically configured to recognize and utilize the proper mode.

Figure 36. USB Connection

6.4 Power Button Design

The power button design is highlighted in Figure 37.

Figure 37. Power Button

6.5 User LEDs

There are four user programmable LEDs on PocketBeagle. The design is highlighted in Figure 38. Table 6 Provides the LED control signals and pins. A logic level of "1" will cause the LEDs to turn on.

Figure 38. User LEDs

Table 6. User LED Control Signals/Pins
LED Signal Name Proc Ball SiP Ball
USR0 GPIO1_21 V15 P13
USR1 GPIO1_22 U15 T14
USR2 GPIO1_23 T15 R14
USR3 GPIO1_24 V16 P14

6.6 JTAG Pads

There are 7 pads on the bottom of PocketBeagle to connect JTAG for debugging. The design is highlighted in Figure 39. More information regarding JTAG debugging can be found at 'www.ti.com/jtag'

Figure 39. JTAG Pads Design

6.7 PRU-ICSS

The Programmable Real-Time Unit Subsystem and Industrial Communication SubSystem (PRU-ICSS) module is located inside the AM3358 processor, which is inside the Octavo Systems SiP. Commonly referred to as just the "PRU", this little subsystem will unleash a lot of performance for you to use in your application. Consisting of dual 32-bit RISC cores (Programmable Real-Time Units, or PRUs), data and instruction memories, internal peripheral modules, and an interrupt controller (INTC). The programmable nature of the PRU-ICSS, along with their access to pins, events and all SoC resources, provides flexibility in implementing fast real-time responses, specialized data handling operations, custom peripheral interfaces, and in offloading tasks from the other processor cores of the system-on-chip (SoC). Access to these pins is provided by PocketBeagle's expansion headers and is multiplexed with other functions on the board. Access is not provided to all of the available pins.

Some getting started information can be found on https://beagleboard.org/pru.

Additional documentation is located on the Texas Instruments website at processors.wiki.ti.com/index.php/PRU-ICSS and also located at http://github.com/beagleboard/am335x_pru_package.

Example projects using the PRU-ICSS can be found at processors.wiki.ti.com/index.php/PRU_Projects.

6.7.1 PRU-ICSS Features

The features of the PRU-ICSS include:

Two independent programmable real-time (PRU) cores:

  • 32-Bit Load/Store RISC architecture
  • 8K Byte instruction RAM (2K instructions) per core
  • 8K Bytes data RAM per core
  • 12K Bytes shared RAM
  • Operating frequency of 200 MHz
  • PRU operation is little endian similar to ARM processor
  • All memories within PRU-ICSS support parity
  • Includes Interrupt Controller for system event handling
  • Fast I/O interface
– 16 input pins and 16 output pins per PRU core. (Not all of these are accessible on the PocketBeagle. Please check the Pin Table below for PRU-ICSS features available through the P1 and P2 headers.)

6.7.2 PRU-ICSS Block Diagram

Figure 40 is a high level block diagram of the PRU-ICSS.

Figure 40. PRU-ICSS Block Diagram

6.7.3 PRU-ICSS Pin Access

Both PRU 0 and PRU1 are accessible from the expansion headers. Listed below are the ports that can be accessed on each PRU.

Table 6. below shows which PRU-ICSS signals can be accessed on PocketBeagle and on which connector and pins on which they are accessible. Some signals are accessible on the same pins.

Table 6. PRU0 and PRU1 Access

Use scroll bar at bottom of chart to see additional features in columns to the right. When printing this document, you will need to print this chart separately.

Header.Pin Silkscreen Processor Ball SiP Ball Mode3 Mode4 Mode5 Mode6 Note
P1.02 A6/87 R5 F2 pr1_pru1_pru_r30_9 (Output) pr1_pru1_pru_r31_9 (Input)
P1.04 89 R6 E1 pr1_pru1_pru_r30_11 (Output) pr1_pru1_pru_r31_11 (Input)
P1.06 SPI0_CS A16 A14 pr1_uart0_txd (Output) UART Transmit Data
P1.08 SPI0_CLK A17 A13 pr1_uart0_cts_n (Input) UART Clear to Send
P1.10 SPI0_MISO B17 B13 pr1_uart0_rts_n (Output) UART Request to Send
P1.12 SPI0_MOSI B16 B14 pr1_uart0_rxd (Input) UART Receive Data
P1.20 20 D14 B4 pr1_pru0_pru_r31_16 (Input)
P1.26 I2C2_SDA D18 B10 pr1_uart0_cts_n (Input) UART Clear to Send
P1.28 I2C2_SCL D17 A10 pr1_uart0_rts_n (Output) UART Request to Send
P1.29 PRU0_7 A14 C4 pr1_pru0_pru_r30_7 (Output) pr1_pru0_pru_r31_7 (Input)
P1.30 U0_TX E16 B12 pr1_pru1_pru_r30_15 (Output) pr1_pru1_pru_r31_15 (Input)
P1.31 PRU0_4 B12 A3 pr1_pru0_pru_r30_4 (Output) pr1_pru0_pru_r31_4 (Input)
P1.32 U0_RX E15 A12 pr1_pru1_pru_r30_14 (Output) pr1_pru1_pru_r31_14 (Input)
P1.33 PRU0_1 B13 A2 pr1_pru0_pru_r30_1 (Output) pr1_pru0_pru_r31_1 (Input)
P1.35 P1.10 V5 F1 pr1_pru1_pru_r30_10 (Output) pr1_pru1_pru_r31_10 (Input)
P1.36 PWM0A A13 A1 pr1_pru0_pru_r30_0 (Output) pr1_pru0_pru_r31_0 (Input)
P2.09 I2C1_SCL D15 B11 pr1_uart0_txd (Output) pr1_pru0_pru_r31_16 (Input) UART Transmit Data
P2.11 I2C1_SDA D16 A11 pr1_uart0_rxd (Input) pr1_pru1_pru_r31_16 (Input) UART Receive Data
P2.17 65 V12 T7 pr1_mdio_mdclk MDIO Clk
P2.18 47 U13 P7 pr1_ecap0_ecap_capin_apwm_o pr1_pru0_pru_r31_15 (Input) Enhanced capture input or Auxiliary PWM out
P2.20 64 T13 R7 pr1_mdio_data MDIO Data
P2.22 46 V13 T6 pr1_pru0_pru_r31_14 (Input)
P2.24 48 T12 P6 pr1_pru0_pru_r30_14 (Output)
P2.28 PRU0_6 D13 C3 pr1_pru0_pru_r30_6 Output) pr1_pru0_pru_r31_6 (Input)
P2.29 SPI1_CLK C18 C5 pr1_ecap0_ecap_capin_apwm_o Enhanced capture input or Auxiliary PWM out
P2.30 PRU0_3 C12 B1 pr1_pru0_pru_r30_3 (Output) pr1_pru0_pru_r31_3 (Input)
P2.31 SPI1_CS A15 A4 pr1_pru1_pru_r31_16 (Input)
P2.32 PRU0_2 D12 B2 pr1_pru0_pru_r30_2 (Output) pr1_pru0_pru_r31_2 (Input)
P2.33 45 R12 R6 pr1_pru0_pru_r30_15 (Output)
P2.34 PRU0_5 C13 B3 pr1_pru0_pru_r30_5 (Output) pr1_pru0_pru_r31_5 (Input)
P2.35 A5/86 U5 F3 pr1_pru1_pru_r30_8 (Output) pr1_pru1_pru_r31_8 (Input)

7.0 Connectors

This section describes each of the connectors on the board.

7.1 Expansion Header Connectors

The expansion interface on the board is comprised of two 36 pin connectors. The two Expansion Header Connectors on PocketBeagle are labeled P1 and P2. The connections are a standard 100 mil distance so that they can be compatible with many standard expansion items. The silkscreen for the headers on the bottom of the board provides the easiest way to identify them. See Figure 41.

Figure 41. Expansion Headers for PocketBeagle

All signals on the expansion headers are 3.3V unless otherwise indicated.

NOTE: Do not connect 5V logic level signals to these pins or the board will be damaged.

NOTE: DO NOT APPLY VOLTAGE TO ANY I/O PIN WHEN POWER IS NOT SUPPLIED TO THE BOARD. IT WILL DAMAGE THE PROCESSOR AND VOID THE WARRANTY.

NO PINS ARE TO BE DRIVEN UNTIL AFTER THE SYS_RESET LINE GOES HIGH.

Figure 42 shows a color coded chart with an overview of the most popular functions of PocketBeagle's Expansion Header pins. The Header Pin tables in Sections 7.1.1 and 7.1.2 show the full pin assignments for each header.

Figure 42. Expansion Header Popular Functions - Color Coded

7.1.1 P1 Header

Figure 43 shows the schematic diagram for the P1 Header.

Figure 43 P1 Header

Table 7. P1 Header Pinout

Use scroll bar at bottom of chart to see additional features in columns to the right. When printing this document you will need to print this chart separately.

Header.Pin Silkscreen PocketBeagle wiring Proc Ball SiP Ball Mode0 (Name) Mode1 Mode2 Mode3 Mode4 Mode5 Mode6 Mode7
P1.01 VIN P1.01 (VIN) P10 & R10 & T10 VIN
P1.02 A6/87 P1.02 (AIN6/GPIO87) A8 C9 ain6
P1.02 A6/87 P1.02 (AIN6/GPIO87) R5 F2 lcd_hsync gpmc_a9 gpmc_a2 pr1_edio_data_in3 pr1_edio_data_out3 pr1_pru1_pru_r30_9 pr1_pru1_pru_r31_9 gpio2_23
P1.03 USB1_EN P1.03 (USB1-DRVVBUS) F15 M14 USB1_DRVVBUS - - - - - - gpio3_13
P1.04 89 P1.04 (PRU1.11) R6 E1 lcd_ac_bias_en gpmc_a11 pr1_mii1_crs pr1_edio_data_in5 pr1_edio_data_out5 pr1_pru1_pru_r30_11 pr1_pru1_pru_r31_11 gpio2_25
P1.05 USB1_VB P1.05 (USB1-VBUS) T18 M15 USB1_VBUS - - - - - - -
P1.06 SPI0_CS P1.06 (SPI0-CS) A16 A14 spi0_cs0 mmc2_sdwp I2C1_SCL ehrpwm0_synci pr1_uart0_txd pr1_edio_data_in1 pr1_edio_data_out1 gpio0_5
P1.07 USB1_VI P1.07 (VIN-USB) P9 &R9 &T9 VIN-USB
P1.08 SPI0_CLK P1.08 (SPI0-CLK) A17 A13 spi0_sclk uart2_rxd I2C2_SDA ehrpwm0A pr1_uart0_cts_n pr1_edio_sof EMU2 gpio0_02
P1.09 USB1 - P1.09 (USB1-DN) R18 L16 USB1_DM - - - - - - -
P1.10 SPI0_MISO P1.10 (SPI0-MISO) B17 B13 spi0_d0 uart2_txd I2C2_SCL ehrpwm0B pr1_uart0_rts_n pr1_edio_latch_in EMU3 gpio0_3
P1.11 USB1 + P1.11 (USB1-DP) R17 L15 USB1_DP - - - - - - -
P1.12 SPI0_MOSI P1.12 (SPI0-MOSI) B16 B14 spi0_d1 mmc1_sdwp I2C1_SDA ehrpwm0_tripzone_input pr1_uart0_rxd pr1_edio_data_in0 pr1_edio_data_out0 gpio0_04
P1.13 USB1_ID P1.13 (USB1-ID) P17 L14 USB1_ID - - - - - - -
P1.14 +3.3V P1.14 (VOUT-3.3V) F6 & F7 & G6 & G7 VOUT-3.3V
P1.15 USB1_GND P1.15 (GND) GND
P1.16 GND P1.16 (GND) GND
P1.17 AIN(1.8V)- P1.17 (VREFN) A9 B9 VREFN
P1.18 AIN(1.8V)A+ P1.18 (VREFP) B9 B7 VREFP
P1.19 AIN(1.8V)0 P1.19 (AIN0-1.8V) B6 A8 ain0
P1.20 20 P1.20 (PRU0.16) D14 B4 xdma_event_intr1 - tclkin clkout2 timer7 pr1_pru0_pru_r31_16 EMU3 gpio0_20
P1.21 AIN(1.8V)1 P1.21 (AIN1-1.8V) C7 B8 ain1
P1.22 GND P1.22 (GND) GND
P1.23 AIN(1.8V)2 P1.23 (AIN2-1.8V) B7 B6 ain2
P1.24 VOUT P1.24 (VOUT-5V) K6 & K7 & L6 & L7 VOUT-5V
P1.25 AIN(1.8V)3 P1.25 (AIN3-1.8V) A7 C6 ain3
P1.26 I2C2_SDA P1.26 (I2C2-SDA) D18 B10 uart1_ctsn timer6 dcan0_tx I2C2_SDA spi1_cs0 pr1_uart0_cts_n pr1_edc_latch0_in gpio0_12
P1.27 AIN(1.8V)4 P1.27 (AIN4-1.8V) C8 C7 ain4
P1.28 I2C2_SCL P1.28 (I2C2-SCL) D17 A10 uart1_rtsn timer5 dcan0_rx I2C2_SCL spi1_cs1 pr1_uart0_rts_n pr1_edc_latch1_in gpio0_13
P1.29 PRU0_7 P1.29 (PRU0.7) A14 C4 mcasp0_ahclkx eQEP0_strobe mcasp0_axr3 mcasp1_axr1 EMU4 pr1_pru0_pru_r30_7 pr1_pru0_pru_r31_7 gpio3_21
P1.30 U0_TX P1.30 (UART0-TX) E16 B12 uart0_txd spi1_cs1 dcan0_rx I2C2_SCL eCAP1_in_PWM1_out pr1_pru1_pru_r30_15 pr1_pru1_pru_r31_15 gpio1_11
P1.31 PRU0_4 P1.31 (PRU0.4) B12 A3 mcasp0_aclkr eQEP0A_in mcasp0_axr2 mcasp1_aclkx mmc0_sdwp pr1_pru0_pru_r30_4 pr1_pru0_pru_r31_4 gpio3_18
P1.32 U0_RX P1.32 (UART0-RX) E15 A12 uart0_rxd spi1_cs0 dcan0_tx I2C2_SDA eCAP2_in_PWM2_out pr1_pru1_pru_r30_14 pr1_pru1_pru_r31_14 gpio1_10
P1.33 PRU0_1 P1.33 (PRU0.1) B13 A2 mcasp0_fsx ehrpwm0B - spi1_d0 mmc1_sdcd pr1_pru0_pru_r30_1 pr1_pru0_pru_r31_1 gpio3_15
P1.34 26 P1.34 (GPIO0.26) T11 R5 gpmc_ad10 lcd_data21 mmc1_dat2 mmc2_dat6 ehrpwm2_tripzone_input pr1_mii0_txen - gpio0_26
P1.35 P1.10 P1.35 (PRU1.10) V5 F1 lcd_pclk gpmc_a10 pru_mii0_crs pr1_edio_data_in4 pr1_edio_data_out4 pr1_pru1_pru_r30_10 pr1_pru1_pru_r31_10 gpio2_24
P1.36 PWM0A P1.36 (PWM0A) A13 A1 mcasp0_aclkx ehrpwm0A - spi1_sclk mmc0_sdcd pr1_pru0_pru_r30_0 pr1_pru0_pru_r31_0 gpio3_14

7.1.2 P2 Header

Figure 44 shows the schematic diagram for the P2 Header.

Figure 44. P2 Header

Table 8. P2 Header Pinout

Use scroll bar at bottom of chart to see additional features in columns to the right. When printing this document you will need to print this chart separately.

Header.Pin Silkscreen PocketBeagle wiring Proc Ball SiP Ball Mode0 (Name) Mode1 Mode2 Mode3 Mode4 Mode5 Mode6 Mode7
P2.01 PWM1A P2.01 (PWM1A) U14 P12 gpmc_a2 gmii2_txd3 rgmii2_td3 mmc2_dat1 gpmc_a18 pr1_mii1_txd2 ehrpwm1A gpio1_18
P2.02 59 P2.02 (GPIO1.27) V17 T16 gpmc_a11 gmii2_rxd0 rgmii2_rd0 rmii2_rxd0 gpmc_a27 pr1_mii1_rxer mcasp0_axr1 gpio1_27
P2.03 23 P2.03 (GPIO0.23) T10 P5 gpmc_d9 lcd_data22 mmc1_dat1 mmc2_dat5 ehrpwm2B pr1_mii0_col - gpio0_23
P2.04 58 P2.04 (GPIO1.26) T16 R15 gpmc_a10 gmii2_rxd1 rgmii2_rd1 rmii2_rxd1 gpmc_a26 pr1_mii1_rxdv mcasp0_axr0 gpio1_26
P2.05 U1_RX P2.05 (UART4-RX) T17 P15 gpmc_wait0 gmii2_crs gpmc_csn4 rmii2_crs_dv mmc1_sdcd pr1_mii1_col uart4_rxd gpio0_30
P2.06 57 P2.06 (GPIO1.25) U16 T15 gpmc_a9 gmii2_rxd2 rgmii2_rd2 mmc2_dat7 / rmii2_crs_dv gpmc_a25 pr1_mii_mr1_clk mcasp0_fsx gpio1_25
P2.07 U1_TX P2.07 (UART4-TX) U17 R16 gpm_ wp gmii2_rxerr gpmc_csn5 rmii2_rxerr mmc2_sdcd pr1_mii1_txen uart4_txd gpio0_31
P2.08 60 P2.08 (GPIO1.28) U18 N14 gpmc_be1n gmii2_col gpmc_csn6 mmc2_dat3 gpmc_dir pr1_mii1_rxlink mcasp0_aclkr gpio1_28
P2.09 I2C1_SCL P2.09 (I2C1-SCL) D15 B11 uart1_txd mmc2_sdwp dcan1_rx I2C1_SCL - pr1_uart0_txd pr1_pru0_pru_r31_16 gpio0_15
P2.10 52 P2.10 (GPIO1.20) R14 R13 gpmc_a4 gmii2_txd1 rgmii2_td1 rmii2_txd1 gpmc_a20 pr1_mii1_txd0 eQEP1A_in gpio1_20
P2.11 I2C1_SDA P2.11 (I2C1-SDA) D16 A11 uart1_rxd mmc1_sdwp dcan1_tx I2C1_SDA - pr1_uart0_rxd pr1_pru1_pru_r31_16 gpio0_14
P2.12 PB P2.12 (POWER_BTN) T11 POWER
P2.13 VOUT P2.13 (VOUT-5V) K6, K7, L6, L7 VOUT-5V
P2.14 BAT + P2.14 (VIN-BAT) P8, R8, T8 VIN-BAT
P2.15 GND P2.15 (GND) GND
P2.16 BAT - P2.16 (BAT-TEMP) N6 BAT-TEMP
P2.17 65 P2.17 (GPIO2.1) V12 T7 gpmc_clk lcd_memory_clk gpmc_wait1 mmc2_clk pr1_mii1_crs pr1_mdio_mdclk mcasp0_fsr gpio2_01
P2.18 47 P2.18 (PRU0.15i) U13 P7 gpmc_ad15 lcd_data16 mmc1_dat7 mmc2_dat3 eQEP2_strobe pr1_ecap0_ecap_capin_apwm_o pr1_pru0_pru_r31_15 gpio1_15P
2.19 27 P2.19 (GPIO0.27) U12 T5 gpmc_ad11 lcd_data20 mmc1_dat3 mmc2_dat7 ehrpwm0_synco pr1_mii0_txd3 - gpio0_27
P2.20 64 P2.20 (GPIO2.0) T13 R7 gpmc_csn3 gpmc_a3 rmii2_crs_dv mmc2_cmd pr1_mii0_crs pr1_mdio_data EMU4 gpio2_00
P2.21 GND P2.21 (GND) GND
P2.22 46 P2.22 (GPIO1.14) V13 T6 gpmc_ad14 lcd_data17 mmc1_dat6 mmc2_dat2 eQEP2_index pr1_mii0_txd0 pr1_pru0_pru_r31_14 gpio1_14
P2.23 +3.3V P2.23 (VOUT-3.3V) F6 & F7 & G6 & G7 VOUT-3.3V
P2.24 48 P2.24 (GPIO1.12) T12 P6 gpmc_ad12 lcd_data19 mmc1_dat4 mmc2_dat0 eQEP2A_in pr1_mii0_txd2 pr1_pru0_pru_r30_14 gpio1_12
P2.25 SPI1_MOSI P2.25 (SPI1-MOSI) E17 C13 uart0_rtsn uart4_txd dcan1_rx I2C1_SCL spi1_d1 spi1_cs0 pr1_edc_sync1_out gpio1_09
P2.26 RST P2.26 (NRESET) A10 R11 nRESETIN_OUT - - - - - - -
P2.27 SPI1_MISO P2.27 (SPI1-MISO) E18 C12 uart0_ctsn uart4_rxd dcan1_tx I2C1_SDA spi1_d0 timer7 pr1_edc_sync0_out gpio1_08
P2.28 PRU0_6 P2.28 (PRU0.6) D13 C3 mcasp0_axr1 eQEP0_index - mcasp1_axr0 EMU3 pr1_pru0_pru_r30_6 pr1_pru0_pru_r31_6 gpio3_20
P2.29 SPI1_CLK P2.29 (SPI1-CLK) C18 C5 eCAP0_in_PWM0_out uart3_txd spi1_cs1 pr1_ecap0_ecap_capin_apwm_o spi1_sclk mmc0_sdwp xdma_event_intr2 gpio0_7
P2.30 PRU0_3 P2.30 (PRU0.3) C12 B1 mcasp0_ahclkr ehrpwm0_synci mcasp0_axr2 spi1_cs0 eCAP2_in_PWM2_out pr1_pru0_pru_r30_3 pr1_pru0_pru_r31_3 gpio3_17
P2.31 SPI1_CS P2.31 (SPI1-CS) A15 A4 xdma_event_intr0 - timer4 clkout1 spi1_cs1 pr1_pru1_pru_r31_16 EMU2 gpio0_19
P2.32 PRU0_2 P2.32 (PRU0.2) D12 B2 mcasp0_axr0 ehrpwm0_tripzone_input - spi1_d1 mmc2_sdcd pr1_pru0_pru_r30_2 pr1_pru0_pru_r31_2 gpio3_16
P2.33 45 P2.33 (GPIO1.13) R12 R6 gpmc_ad13 lcd_data18 mmc1_dat5 mmc2_dat1 eQEP2B_in pr1_mii0_txd1 pr1_pru0_pru_r30_15 gpio1_13
P2.34 PRU0_5 P2.34 (PRU0.5) C13 B3 mcasp0_fsr eQEP0B_in mcasp0_axr3 mcasp1_fsx EMU2 pr1_pru0_pru_r30_5 pr1_pru0_pru_r31_5 gpio3_19
P2.35 A5/86 P2.35 (AIN5/GPIO86) B8 C8 ain5
P2.35 A5/86 P2.35 (AIN5/GPIO86) U5 F3 lcd_vsync gpmc_a8 gpmc_a1 pr1_edio_data_in2 pr1_edio_data_out2 pr1_pru1_pru_r30_8 pr1_pru1_pru_r31_8 gpio2_22

7.2 mikroBUS socket connections

mikroBUS and, by extension "mikroBUS Click boards", are trademarks of MikroElektronika. We do not make any claims of compatibility nor adherence to their specification. We've just seen that many of the Click boards "just work".

The Expansion Headers on PocketBeagle have been designed to accept up to two Click Boards added to the header pins at the same time. This provides an exciting opportunity to add functionality easily to PocketBeagle from 'hundreds of existing add-on Click Boards'.

The mikroBUS standard comprises a pair of 1×8 female headers with a standardized pin configuration. The pinout (always laid out in the same order) consists of three groups of communications pins (SPI, UART and I2C), six additional pins (PWM, Interrupt, Analog input, Reset and Chip select), and two power groups (+3.3V and 5V).

Figure 45. mikroBUS

The Expansion Header pin alignment enables 2 Click Boards on the top side of PocketBeagle using the inside rails of the headers. This leaves the outside rails open to be accessed from either the top or the bottom of PocketBeagle. Place each Click Board into the position shown in Figure 46, with one Click Board facing each direction. When choosing Click boards, make sure you are checking that they meet the 3.3V requirements for PocketBeagle. A growing number of community members are trying out various Click Boards and posting results on the 'PocketBeagle Wiki mikroBus Click Boards page'.

Figure 46. PocketBeagle Both Headers

7.3 Setting up an additional USB Connection

You can add an additional USB connection to PocketBeagle easily by connecting a microUSB breakout. By default in the current software, the system should be configured to use this port as a host. Keep up to date on this project on the 'PocketBeagle Wiki FAQ'.

8.0 PocketCape Support

This is a placeholder for recommendations for those building their own PocketCape designs. If you'd like to join the conversation 'check out the discussion on the google group for PocketBeagle'

9.0 PocketBeagle Mechanical

9.1 Dimensions and Weight

Size: 2.21” x 1.38” (56mm x 35mm)

Max height: .197” (5mm)

PCB size: 55mm x 35mm

PCB Layers: 4

PCB thickness: 1.6mm

RoHS Compliant: Yes

Weight: 10g

Rough model can be found at github.com/beagleboard/pocketbeagle/tree/master/models

10.0 Additional Pictures

Figure 47. PocketBeagle Front BW

Figure 48. PocketBeagle Back BW

11.0 Support Information

All support for this design is through the BeagleBoard.org community at:

11.1 Hardware Design

Design documentation can be found on the wiki. https://github.com/beagleboard/pocketbeagle Including:

11.2 Software Updates

It is a good idea to always use the latest software. Instructions for how to update your software to the latest version can be found at:

Download the latest software files from beagleboard.org/latest-images

11.5 Export Information

11.4 RMA Support

If you feel your board is defective or has issues and before returning merchandise, please seek approval from the manufacturer using beagleboard.org/support/rma. You will need the manufacturer, model, revision and serial number of the board.

11.5 Getting Help

If you need some up to date troubleshooting techniques, the Wiki is a great place to start github.com/beagleboard/pocketbeagle/wiki.

If you need professional support, check out beagleboard.org/resources.

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