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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<style type="text/css">
@import url('../css/main.css');
</style>
<title>How to programme an SPI flash chip with the BeagleBone Black</title>
</head>
<body>
<div class="section">
<h1 id="pagetop">How to programme an SPI flash chip with the BeagleBone Black</h1>
<p>
This document exists as a guide for reading from or writing to an SPI flash chip with the BeagleBone Black,
using the <a href="http://flashrom.org/Flashrom">flashrom</a> software.
BeagleBone Black rev. C was used when creating this guide, but earlier revisions
may also work.
</p>
<p><a href="index.html">Back to previous index</a></p>
</div>
<div class="section" id="hardware_requirements">
<h1>Hardware requirements</h1>
<p>
Shopping list (pictures of this hardware is shown later):
</p>
<ul>
<li>
External SPI programmer: <b>BeagleBone Black</b> (rev. C)
is highly recommended. Sometimes referred to as 'BBB'.
<a href="http://beagleboard.org/black">This page</a> contains a list of distributors.
</li>
<li>
Electrical tape: cover the entire bottom surface of the BBB (the part that
rests on a surface). This is important, when placing the BBB on top of a board
so that nothing shorts.
</li>
<li>
Clip for connecting to the flash chip: if you have a SOIC-16
flash chip (16 pins), you will need the <b>Pomona 5252</b>
or equivalent. For SOIC-8 flash chips (8 pins), you will
need the <b>Pomona 5250</b> or equivalent. Do check which chip you have,
before ordering a clip. Also, make sure to buy at least two clips
(they break easily).
</li>
<li>
<b>External 3.3V DC power supply</b>, for powering the flash chip.
An ATX power supply / PSU (common on Intel/AMD desktop computers) will work for this.
</li>
<li>
<b>External 5V DC power supply</b>, for powering the BBB.
The BeagleBone can have power supplied via USB, but a
dedicated power supply is recommended.
</li>
<li>
<b>Pin header / jumper cables</b> (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.
</li>
<li>
<b>Mini USB A-B cable</b> (the BeagleBone probably already comes
with one.)
</li>
<li>
<b>FTDI TTL cable or debug board</b>, for accessing the serial console on your BBB.
<a href="http://elinux.org/Beagleboard:BeagleBone_Black_Serial">This page</a> contains
a list.
</li>
</ul>
<p>
<a href="#pagetop">Back to top of page.</a>
</p>
</div>
<div class="section" id="psu33">
<h1>Setting up the 3.3V DC PSU</h1>
<p>
ATX PSU pinouts are on <a href="https://en.wikipedia.org/wiki/Power_supply_unit_%28computer%29#Wiring_diagrams">wikipedia</a>
</p>
<p>
On 20-pin ATX PSUs, you can use pin 1 or 2 (orange) for 3.3V, and any of the ground/earth sources (black cables).
Short PS_ON# / Power on (green) to a ground (black. there is one right next to it) using a wire/paperclip/jumper then
power on the PSU.
</p>
<p>
On newer 24-pin ATX PSUs, there is an additional 3.3V (orange) on pin 12.
</p>
<p>
You only need one 3.3V supply and one ground for the flash chip, after grounding PS_ON# to ground.
Multiple 3.3V supplies means that you could theoretically power multiple flash chips at once with the
same PSU.
</p>
<p>
The male end of a 0.1" or 2.54mm header cable is not thick enough to remain permanently
connected to the ATX PSU on its own.
When connecting header cables to the connector on the ATX PSU, use a female end attached to
a thicker piece of wire (you could use a paper clip), or wedge the male end of the jumper cable
into the sides of the hole in the connector, instead of going through the centre.
</p>
<p>
Here is an example set up:<br/>
<img src="images/x200/psu33.jpg" alt="" title="Copyright © 2015 Patrick "P. J." McDermott <pj@pehjota.net> CC BY-SA 3.0 or later" />
</p>
</div>
<div class="section" id="bbb_access">
<h1>Accessing the operating system on the BBB</h1>
<p>
The operating system on your BBB will probably have an SSH daemon
running where the root account has no password. Use SSH to access
the operating system and set a root password. By default, the OS
on your BBB will most likely use DHCP, so it should already have an IP
address.
</p>
<p>
You will also be using the OS on your BBB for programming an SPI flash chip.
</p>
<h2>Alternatives to SSH (in case SSH fails)</h2>
<p>
You can also use a serial FTDI debug board with GNU Screen, to access the serial console.<br/>
# <b>screen /dev/ttyUSB0 115200</b><br/>
Here are some example photos:<br/>
<img src="images/x200/ftdi.jpg" alt="" />
<img src="images/x200/ftdi_port.jpg" alt="" /><br/>
</p>
<p>
You can also connect the USB cable from the BBB to another computer and a new network interface will appear,
with its own IP address. This is directly accessible from SSH, or screen:<br/>
# <b>screen /dev/ttyACM0 115200</b>
</p>
<p>
You can also access the uboot console, using the serial method
instead of SSH.
</p>
</div>
<div class="section" id="spidev">
<h1>Setting up spidev on the BBB</h1>
<p>
Log on as root on the BBB, using either SSH or a serial console as defined in
<a href="#bbb_access">#bbb_access</a>. Make sure that you have internet access
on your BBB.
</p>
<p>
Follow the instructions at <a href="http://elinux.org/BeagleBone_Black_Enable_SPIDEV#SPI0">http://elinux.org/BeagleBone_Black_Enable_SPIDEV#SPI0</a>
up to (and excluding) the point where it tells you to modify uEnv.txt
</p>
<p>
You need to update the software on the BBB first. If you have an
element14 brand BBB (sold by Premier Farnell plc. stores like
Farnell element14, Newark element14, and Embest), you may need
to <a href="https://groups.google.com/forum/?_escaped_fragment_=msg/beagleboard/LPjCn4LEY2I/alozBGsbTJMJ#!msg/beagleboard/LPjCn4LEY2I/alozBGsbTJMJ">work around a bug</a>
in the LED aging init script before you can update your
software. If you don't have a file named
/etc/init.d/led_aging.sh, you can skip this step and update your
software as described below. Otherwise, replace the contents of
this file with:
</p>
<pre>
#!/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
</pre>
</p>
Run <b>apt-get update</b> and <b>apt-get upgrade</b> then reboot the BBB, before continuing.
</p>
<p>
Check that the firmware exists:<br/>
# <b>ls /lib/firmware/BB-SPI0-01-00A0.*</b><br/>
Output:
</p>
<pre>
/lib/firmware/BB-SPI0-01-00A0.dtbo
</pre>
<p>
Then:<br/>
# <b>echo BB-SPI0-01 > /sys/devices/bone_capemgr.*/slots</b><br/>
# <b>cat /sys/devices/bone_capemgr.*/slots</b><br/>
Output:
</p>
<pre>
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
</pre>
<p>
Verify that the spidev device now exists:<br/>
# <b>ls -al /dev/spid*</b><br/>
Output:
</p>
<pre>
crw-rw---T 1 root spi 153, 0 Nov 19 21:07 /dev/spidev1.0
</pre>
<p>
Now the BBB is ready to be used for flashing. Make this persist
across reboots:<br/>
In /etc/default/capemgr add <b>CAPE=BB-SPI0-01</b> at the end
(or change the existing <b>CAPE=</b> entry to say that, if an
entry already exists.
</p>
<p>
Get flashrom from the libreboot_util release archive, or build it from libreboot_src/git if you need to.
An ARM binary (statically compiled) for flashrom exists in libreboot_util releases.
</p>
<p>
Now test flashrom:<br/>
# <b>./flashrom -p linux_spi:dev=/dev/spidev1.0,spispeed=512</b><br/>
Output:
</p>
<pre>
Calibrating delay loop... OK.
No EEPROM/flash device found.
Note: flashrom can never write if the flash chip isn't found automatically.
</pre>
<p>
This means that it's working (the clip isn't connected to any flash chip,
so the error is fine).
</p>
</div>
<div class="section" id="clip">
<h1>
Connecting the Pomona 5250/5252
</h1>
<p>
Use this image for reference when connecting the pomona to the BBB:
<a href="http://beagleboard.org/Support/bone101#headers">http://beagleboard.org/Support/bone101#headers</a>
(D0 = MISO or connects to MISO).
</p>
<p>
The following shows how to connect clip to the BBB (on the P9 header), for SOIC-16 (clip: Pomona 5252):
</p>
<pre>
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
<i>This is how you will connect. Numbers refer to pin numbers on the BBB, on the plugs near the DC jack.</i>
</pre>
<p>
The following shows how to connect clip to the BBB (on the P9 header), for SOIC-8 (clip: Pomona 5250):
</p>
<pre>
18 - - 1
22 - - NC
NC - - 21
3.3V PSU RED - - 17 - this is pin 1 on the flash chip
<i>This is how you will connect. Numbers refer to pin numbers on the BBB, on the plugs near the DC jack.</i>
</pre>
<p>
<b>NC = no connection</b>
</p>
<p>
<b><u>DO NOT</u> connect 3.3V PSU RED yet. ONLY connect this once the pomona is connected to the flash chip.</b>
</p>
<p>
<b>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).</b>
</p>
<p>
if you need to extend the 3.3v psu leads, just use the same colour M-F leads, <b>but</b> keep all other
leads short (10cm or less)
</p>
<p>
You should now have something that looks like this:<br/>
<img src="images/x200/5252_bbb0.jpg" alt="" />
<img src="images/x200/5252_bbb1.jpg" alt="" />
</p>
<p>
<a href="#pagetop">Back to top of page.</a>
</p>
</div>
<div class="section">
<p>
Copyright © 2014, 2015 Francis Rowe <info@gluglug.org.uk><br/>
Copyright © 2015 Patrick "P. J." McDermott <pj@pehjota.net><br/>
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 <a href="../license.txt">../license.txt</a>.
</p>
<p>
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 <a href="../license.txt">../license.txt</a> for more information.
</p>
</div>
</body>
</html>
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