Setup the BeagleBone Black as an SPI flashrom programmer

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# Hardware requirements

Shopping list (pictures of this hardware is shown later):

- External SPI programmer: BeagleBone Black (rev. C) is highly recommended. Sometimes referred to as 'BBB'.
- Clip for connecting to the flash chip: Pomona 5250 (SOIC-8) or Pomona 5250 (SOIC-16) is recommended (X200S and X200 Tablet users will need a soldering iron instead, because of the type of package the flash chip is in on those machines).
- External 3.3V DC power supply. The one used by this author has the label HF100W-SF-3.3 on it, but any decent supply will be fine. Some people use the 3.3V from an ATX PSU for instance (the kind that you get on a typical Intel/AMD desktop computer. 6A supply should be fine, the one used by this author is 20A (it won't actually use that, it's just what the PSU is capable of).
- Dupont jumper cables (2.54mm / 0.1" headers) You should get male-male, male-female and female-female cables in 10cm and 20cm sizes. Just get a load of them.
- Mini USB A-B cable (the BeagleBone probably already comes with one.)
- FTDI serial board, for unbricking the BeagleBone if necessary.
- 5V DC power supply (from wall outlet to the BeagleBone). The BeagleBone can have power supplied via USB, but a dedicated power supply is recommended.

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# Configuring the BeagleBone Black

## Setting up the 3.3V DC PSU

With my PSU, first I had wire up the mains power cable. Any clover or kettle lead will do. Cut the end off (not the one that goes in the wall, but the kettle/clover connector). Strip the protection away by a decent length, then strip the wires inside so that a decent amount of copper is shown. Then wire up earth/live/neutral. This will vary according to what country you live in and/or the colour codes that your cable uses inside. Make sure to get this right, as a botched job could result in extreme damage to you and your surroundings. Here's what mine looks like after wiring up the power cable: images/x200/psu_power.jpg - also, make sure that the plug (for the wall) has the correct fuse. In my case I had a 240V wall socket, and the device says that it accepts 1.5A at that voltage, so I used the smallest fuse available (3A). For 110-120V the device says it needs 2.8A. Also, if yours looks like in the image linked above, make sure to wrap electrical tape (lots) around it for safety. (otherwise, don't touch the terminals while the PSU is plugged in).

Now take a red and black 20cm female-female jumper lead, and cut one of the ends off. Strip away the bare copper by about 1 or 1.5cm so you get this: images/x200/stripped_jumper_lead.jpg.

Black goes on -V, red goes on +V. In my case, I removed those screws from my PSU like this: images/x200/psu_screws_removed.jpg. Then,

Then I twisted the exposed copper on the jumper leads (so that they don't fray), and wrapped each to one of the screws each, around it near the head. I then screwed them in: images/x200/psu_jumper_leads.jpg.

If you are using a different PSU, then the steps will change from those above. Anyway, once you are satisfied, continue reading...

## Setting up the BBB

Your BBB will have an sshd with no password on root. Find it's IP address (it will use DHCP by default) and set a root password. The steps below are done while SSH'd into a BBB.

You can also use a serial FTDI debug board, with GNU Screen (example):
# screen /dev/ttyUSB0 115200
images/x200/ftdi.jpg and images/x200/ftdi_port.jpg show an FTDI debug board in use. With screen you can then login as root, like you would using SSH.
Using this, you can also see text output (from kernel, etc) when booting the machine.

You can also simply connect the USB cable from the BBB to another computer and a new network interface will appear, with it's own IP address: this is the BBB. You can SSH into that. Or, you can (example):
# screen /dev/ttyACM0 115200

Since it's a bare board (no case) and you are also touching inside your X200, you should be earthed/grounded. images/x200/strap.jpg shows how I earthed myself. This is to prevent you from causing any ESD damage. The surface that you place components on should also be earthed/grounded. (for this, I used a shielded ESD bag with a wire, copper exposed, attached from the bag to the exposed metal part on a radiator, which was earthed - not professional, but it should work. see images/x200/mat.jpg). Most people ignore this advice and don't ground/earth themselves, at their own risk. You should also store the BBB in a shielded anti-static bag when you are finished with it. (the principles above apply to any computer components, since they are extremely sensitive te ESD).

These instructions may or may not work for you. They are simply the steps that this author took.

setting up SPIDEV on the BBB: http://elinux.org/BeagleBone_Black_Enable_SPIDEV#SPI0 - If you only setup SPI0, you don't have to disable the HDMI out. (you only need one). That guide is for seting up the device overlay for SPIDEV, last part is to make it persist across reboots. Needed to turn the BBB into an SPI flasher.

Don't bother modifying uEnv.txt. it won't work; use the workaround here instead: http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#Loading_custom_capes.

Follow the instructions at http://elinux.org/BeagleBone_Black_Enable_SPIDEV#SPI0 up to (and excluding) the point where it tells you to modify uEnv.txt

You need to update the software on the BBB first. Before being able to use apt-get, I had to use the workaround defined here:
- Replace the contents of /etc/init.d/led_aging.sh with:

    #!/bin/sh -e
    ### BEGIN INIT INFO
    # Provides:          led_aging.sh
    # Required-Start:    $local_fs
    # Required-Stop:     $local_fs
    # Default-Start:     2 3 4 5
    # Default-Stop:      0 1 6
    # Short-Description: Start LED aging
    # Description:       Starts LED aging (whatever that is)
    ### END INIT INFO

    x=$(/bin/ps -ef | /bin/grep "[l]ed_acc")
    if [ ! -n "$x" -a -x /usr/bin/led_acc ]; then
        /usr/bin/led_acc &
    fi

Run apt-get update and apt-get upgrade then reboot the BBB, before continuing.

Run those commands:
# echo BB-SPI0-01 > /sys/devices/bone_capemgr.*/slots
Then I did:
# ls -al /dev/spidev0.*
ls: cannot access /dev/spidev0.*: No such file or directory
Then I rebooted and did:
# cat /sys/devices/bone_capemgr.*/slots
Output:

     0: 54:PF---
     1: 55:PF---
     2: 56:PF---
     3: 57:PF---
     4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G
     5: ff:P-O-L Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI

And then:
# ls /lib/firmware/BB-SPI0-01-00A0.*
Output:

    /lib/firmware/BB-SPI0-01-00A0.dtbo

Then:
# echo BB-SPI0-01 > /sys/devices/bone_capemgr.*/slots
# cat /sys/devices/bone_capemgr.*/slots
Output:

     0: 54:PF---
     1: 55:PF---
     2: 56:PF---
     3: 57:PF---
     4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G
     5: ff:P-O-L Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI
     7: ff:P-O-L Override Board Name,00A0,Override Manuf,BB-SPI0-01

Then check if the device exists:
# ls -al /dev/spidev0.*
Output:

    ls: cannot access /dev/spidev0.*: No such file or directory

It didn't exist under that name, but I then did:
# ls -al /dev/spid*
Output:

    crw-rw---T 1 root spi 153, 0 Nov 19 21:07 /dev/spidev1.0

Now the BBB is ready to be used for flashing. Make this persist across reboots:
In /etc/default/capemgr add CAPE=BB-SPI0-01 at the end (or change the existing CAPE= entry to say that, if an entry already exists.

Now you will download and build flashrom on the BBB.
# apt-get install libpci-dev pciutils zlib1g-dev libftdi-dev build-essential subversion
# svn co svn://flashrom.org/flashrom/trunk flashrom
# cd flashrom/
# make

Now test flashrom:
# ./flashrom -p linux_spi:dev=/dev/spidev1.0,spispeed=512
Output:

    Calibrating delay loop... OK.
    No EEPROM/flash device found.
    Note: flashrom can never write if the flash chip isn't found automatically.

This means that it's working (the clip isn't connected to any flash chip, so the error is fine).

## Connecting the Pomona 5250/5252

Use this image for reference when connecting the pomona to the BBB: http://beagleboard.org/Support/bone101#headers (D0 = MISO or connects to MISO).

The following shows how to connect clip to the BBB (on the P9 header), for SOIC-16 (clip: Pomona 5252):

     NC              -       - 21
     1               -       - 17
     NC              -       - NC
     NC              -       - NC
     NC              -       - NC
     NC              -       - NC
     18              -       - 3.3V PSU RED
     22              -       - NC - this is pin 1 on the flash chip
    This is how you will connect. Numbers refer to pin numbers on the BBB, on the plugs near the DC jack.

The following shows how to connect clip to the BBB (on the P9 header), for SOIC-8 (clip: Pomona 5250):

     18              -       - 1
     22              -       - NC
     NC              -       - 21
     3.3V PSU RED    -       - 17 - this is pin 1 on the flash chip
    This is how you will connect. Numbers refer to pin numbers on the BBB, on the plugs near the DC jack.

NC = no connection

DO NOT connect 3.3V PSU RED yet. ONLY connect this once the pomona is connected to the flash chip.

You also need to connect the BLACK wire from the 3.3V PSU to pin 2 on the BBB (P9 header). It is safe to install this now (that is, before you connect the pomona to the flash chip).

if you need to extend the 3.3v psu leads, just use the same colour M-F leads, but keep all other leads short (10cm or less)

images/x200/5252_bbb0.jpg and images/x200/5252_bbb1.jpg shows a properly wired up BBB with Pomona 5252 before being connected to the flash chip on the X200.

That's basically it. Now refer back to the documentation for how to use this on your board.

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Copyright © 2014 Francis Rowe <info@gluglug.org.uk>
This document is released under the Creative Commons Attribution-ShareAlike 4.0 International Public License and all future versions. A copy of the license can be found at ../license.txt.

This document is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See ../license.txt for more information.