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Getting started with RoadRunner on Berta D2 board

This article explains how to get started with the RoadRunner module and the Berta D2 evaluation board

First steps to do to turn-on your Berta D2 board

Follow the sequence illustrated on this image to turn-on your board:

1) Insert the Road Runner module

Pay attention with the RoadRunner orientation to avoid electrical damages

2) Insert a bootable Linux microSD

You can use one of following microSD:

3) Place the jumper J1 in +5V position

Probably this is already the default position

4) Insert a serial usb adapter to get access to the debug port from a serial terminal

The serial terminal setings are 115200.N,8,1 with no flow control

From the Acme Systems eShop two USB to serial converters are available. You can use any other one but pay attention about the electrical signal levels that must be at 3.3 Volt to avoid board damage.

How to plug the DPI adapter:

EUR 8.00

DPI - Debug Port Interface

DPI is an USB-to-serial interface to link the Acme boards debug port to a PC USB host port and have access at the Linux system console using a terminal emulator program like minicom, putty, hyperterminal, etc.

| Product description |

How to plug the USB-3V-SER adapter:

EUR 8.00

USB-3V-SER - USB to 3V3 serial converter

USB to 3V3 serial converter ad 3.3 volt with separated pin plugs

| Product description |

5) Plug the microUSB connector to turn-on the board

How to enable the Ethernet port

If you are using a ready-to-use microSD, it is configured to get the IP address from your DHCP server

The LAN circuitry is powered-off by default. The line that controls the PHY power-on is wired to the jumper J15. You can also use a normal I/O line from the RoadRunner to TP11 to control the power state of the PHY in order to reduce power consumption when the ETH interface is not needed.

Bootstrap sequence and login from debug port

By default the RoadRunner starts running RomBOOT a first level bootloader stored in the internal MPU ROM. This program at power on sends this message to the debug port:


then it looks for a second level bootloader called at91bootstrap. This program usually is stored by default on the QuadSPI and it starts sending this message to the debug port:

AT91Bootstrap 3.8.8...

If a bootable microSD is present the following messages will appear:

SD/MMC: Image: Read file zImage to 0x22000000
SD: Card Capacity: High or Extended
SD: Specification Version 3.0X
SD/MMC: dt blob: Read file acme-roadrunner.dtb to 0x21000000

Booting zImage ......

Using device tree in place at 0x21000000

Starting linux kernel ..., machid: 0xffffffff

Booting Linux on physical CPU 0x0
Linux version 4.17.89 ....

The Linux Kernel image boot messages will follow.

The file zImage (compressed Linux Kernel image) and acme-roadrunner.dtb device tree blob file must be saved on the first FAT16 or FAT32 partition on the microSD.

After the kernel boot there is a second EXT4 partition present on the microSD with the rootfs contents (Linux system and application programms) that will be loaded and run.

EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext4 filesystem) on device 179:2.
devtmpfs: mounted
Freeing unused kernel memory: 1024K (c0900000 - c0a00000)
systemd[1]: systemd 215 running in system mode. (+PAM +AUDIT +SELINUX +IMA +SYSVINIT +LIBCRYPTSETUP +GCRYPT +)
systemd[1]: Detected architecture 'arm'.

Welcome to Debian GNU/Linux 8 (jessie)!

systemd[1]: Set hostname to .
Debian GNU/Linux 8 roadrunner ttyS0

roadrunner login:

Now you can login as superuser with:

  • User root and Password acmesystems

or as normal user with:

  • User acme and Password acmesystems
Last login: Thu Aug  3 15:21:52 CEST 2017 on ttyS0
Linux roadrunner 4.19.78+ #1 Mon May 18 19:14:49 CEST 2020 armv7l

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.

Login from remote SSH session

By default an SSHD daemon is installed on the Linux microSD. With this program it is possible to access the board from a remote Linux PC using SSH.

Check the IP address assigned to your board by typing:

$ sudo ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:04:25:aa:08:29  
          inet addr:  Bcast:  Mask:
          inet6 addr: fe80::204:25ff:feaa:829/64 Scope:Link
          RX packets:350 errors:0 dropped:0 overruns:0 frame:0
          TX packets:26 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:24755 (24.1 KiB)  TX bytes:2188 (2.1 KiB)
          Interrupt:26 Base address:0x8000

Then you can access from a remote Linux terminal with the command:

$ ssh acme@


$ ssh root@

The password are the same used from the debug port.

The authenticity of host ' (' can't be established.
ECDSA key fingerprint is SHA256:P23roIIWFbcSAew4a/5H0h4l1iubfW8hSYsfPcaCF0g.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '' (ECDSA) to the list of known hosts.
acme@'s password: 

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Sun Jan  1 01:10:11 2012

Where to go now ?

Basically the RoadRunner is a normal Linux Board so all the tutorials available on internet about Linux and Debian Linux distributions could be used also on this board.

From the Debian repository all the packages available for the ARMHF architecure should be working also an RoadRunner without any problem.

To install new packages the command is typically:

$ sudo apt-get update
$ sudo apt-get install [package-name]

A lot of tutorials are available on:

RoadRunner specific doc is avalable here:

For any technical request please use the Acme Systems newsgroups available here:

Berta D2 board anatomy

In this section we will continue with the description of any component available on the Berta D2 board

To know the electrical details about the Berta D2 board read the schematic available here in pdf format:

BOOTOFF and RESET push-buttons

The purpose of the BOOTOFF push-button is to prevent the access of the QuadSPI from the CPU at power on. In this way the RomBOOT bootloader, instead of booting the second level bootloader (at91bootstrap), will enable the USB device port in order to be able to re-program the QuadSPI contents from a connected Linux box running SAM-BA utiity. Hold down the BOOTOFF push-button while pressing the RESET button and release the RESET button first and the BOOTOFF button 1 second later. The RomBOOT message will appear on the debug port and the USB device port will go up to receive command from SAM-BA.

Read the article Write on QuadSPI memory with SAM-BA to know more on how to re-write the RoadRunner QuadSPI.

J13 jumper - Power consumption test point

The J13 pads of the Berta D2 board are used to measure the RoadRunner module power consumption. Those pads are in parallel with a 0.1 Ohm resistor so that if you put a voltmeter on J13, every mV measured corresponds to 10 mA of current consumption @ 3.3 Volt. A summary of the power consumption of the module in several running states is reported here: RoadRunner Power Consumption

J1 jumper - Power supply shutdown mode

The J1 jumper is to select the desired state of the 5V to 3.3V switching buck regulator.

  • Closing +5V - EN3V pins the regulator's ENABLE signal is tied to 5V so it will remains always on regardless of the state of the RoadRunner shutdown line.

  • Closing SHDN - EN3V pins the regulator's ENABLE signal is tied to the RoadRunner shutdown line so, typing this command shutdown -h now, the main 3.3V regulator will power off.

In this state to wake up the RoadRunner you need to put the WKUP line (J3.1) momentarily at GND with a pushbutton or with a wire.

It is also possible to go in shutdown and wake up after an event on a I/O line or with a Real Time Clock timeout.

For example in order to restart the board at a predefined time after the shutdown you can issue the following command immediately before the "shutdown -h now" or "poweroff" command

echo "+30" > /sys/class/rtc/rtc0/wakealarm

During the shutdown time with the J1 jumper in the bottom position the BertaD2 will consume zero from the external power and the supercap will maintain the backup zone with Real Time Clock and the logic to wakeup from external events.

Backup current consumption

You can measure the current consumption in backup mode on the VBAT_SC and VBAT pads shown below.

Those pads are in parallel with a 1000 Ohm resistor so 1 mV measured corresponds to 1 uA (microampere) of current consumption from the backup power source (in the Berta D2 there is a supercapacitor as backup power source).

Ing. Roberto Asquini
Hardware designer, manufactoring engineer, firmware developer and company co-founder
Github repository:
Sergio Tanzilli
System designer, webmaster and Acme Systems co-founder
Personal email:
Webpages: -
Github repositories: and
Telegram group dedicated to the Acme Systems boards:

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EUR 36.00

ROADRUNNER-Q16 - SAMA5D27 System on module (16MB)

RoadRunner D2 is a small and low-cost Linux embedded system on chip

  • Atmel SAMA5D27 MPU
  • 256 MByte of DDR3 RAM
  • 16MB of QuadSPI on-board
  • Extended temperature range (-40° +85°)
| Product description |

EUR 30.00

BERTA-D2 - Basic evaluation board for RoadRunner SOM

Basic evaluation board for RoadRunner SOM:

  • RoadRunner not included
  • MicroSD not included
| Product description |

Technical documentation Buy on-line

Bruna Mandolino