Embedded Xinu - User contributions [en]

Wiring

2006-09-08T20:39:12Z

Justin:

<center>[[Image:Embedsysdiag.png]]</center> 
{| align=right
| [[media:Embedsys2.ps|The postscript file of the diagram.]]
|} 
----
 
* The diagram on the left represents the UART head on the main board of the router. The left pins (2,6,4,8,10) represent the data that is sent and received from the first serial port, the right pins (1,5,3,7,9) the second serial port.

* The diagram in the middle represents the [[Chips|MAX233A transceiver]] needed to convert the voltage used to transmit signals in the router (3.3V) to the RS-232 standard signals to send over the serial port.

* The diagrams on the rights represent two standard DB9F serial ports wired to be DCEs.

Please note that the diagrams do NOT represent actual placement of the pins on the hardware, which may have been moved to simplify the diagram.

File:Embedsys2.ps

2006-09-08T20:28:28Z

Justin: The .ps version of the wiring diagram.

The .ps version of the wiring diagram.

CFE Command Line Interface

2006-09-08T20:17:36Z

Justin:

<pre>CFE> help
Available commands:

rndis Broadcom USB RNDIS utility.
et Broadcom Ethernet utility.
modify Modify flash data.
nvram NVRAM utility.
reboot Reboot.
flash Update a flash memory device
memtest Test memory.
f Fill contents of memory.
e Modify contents of memory.
d Dump memory.
u Disassemble instructions.
autoboot Automatic system bootstrap.
batch Load a batch file into memory and execute it
go Verify and boot OS image.
boot Load an executable file into memory and execute it
load Load an executable file into memory without executing it
save Save a region of memory to a remote file via TFTP
ping Ping a remote IP host.
arp Display or modify the ARP Table
ifconfig Configure the Ethernet interface
show devices Display information about the installed devices.
unsetenv Delete an environment variable.
printenv Display the environment variables
setenv Set an environment variable.
help Obtain help for CFE commands

For more information about a command, enter 'help command-name'
*** command status = 0</pre>

Common Firmware Environment

2006-09-08T18:20:03Z

Justin: /* Getting into CFE */

=== About ===

The Common Firmware Environment (CFE) is the firmware developed by Broadcom for the BCM947xx SoC platform (among others). It is the first code that runs when the router boots and performs functions similar to Apple's Open Firmware:

* Initializes the system
* Sets up a basic environment in which code can run
* Optionally provides a command line interface non-standard usage
* Loads and executes a kernel image (expecting to be jettisoned shortly thereafter)

So, in normal operation, a user will not see CFE working at all; it will load the LinkSys kernel and send it on its merry way without hesitation. For us, however, CFE is crucial, because it provides us with the ability to load an image over the network using TFTP.

We have access to two major documents covering CFE, the reference manual, and the functional specification. Much of the content in these two documents overlaps.

=== Getting into CFE ===

To get into CFE, it will be very helpful to enable "boot wait" from the Administration Tab under the router's Web GUI. This will cause the router to wait on startup for a signal to stop booting into the firmware and enter CFE.

Once you have that set up and you've [[How_to_connect|connected]] to the router, just type "reboot" (assuming [[OpenWRT]] is installed, it may be different for other firmwares) to reboot the router. This can also be done by power-cycling the router. As it's booting up, send a continuous stream of Ctrl+C characters to cancel booting and you'll be entered right into CFE.

From there, you can prod around CFE's features or load your own kernel using the [[CFE_Command_Line_Interface|command line interface]].

Common Firmware Environment

2006-09-08T18:17:59Z

Justin:

=== About ===

The Common Firmware Environment (CFE) is the firmware developed by Broadcom for the BCM947xx SoC platform (among others). It is the first code that runs when the router boots and performs functions similar to Apple's Open Firmware:

* Initializes the system
* Sets up a basic environment in which code can run
* Optionally provides a command line interface non-standard usage
* Loads and executes a kernel image (expecting to be jettisoned shortly thereafter)

So, in normal operation, a user will not see CFE working at all; it will load the LinkSys kernel and send it on its merry way without hesitation. For us, however, CFE is crucial, because it provides us with the ability to load an image over the network using TFTP.

We have access to two major documents covering CFE, the reference manual, and the functional specification. Much of the content in these two documents overlaps.

=== Getting into CFE ===

To get into CFE, it will be very helpful to enable "boot wait" from the Administration Tab under the router's Web GUI. This will cause the router to wait on startup for a signal to stop booting the loaded kernel and enter CFE.

Once you have that set up and you've [[How_to_connect|connected]] to the router, just type "reboot" (assuming [[OpenWRT]] is installed, it may be different for other firmwares) to reboot the router. This can also be done by power-cycling the router. As it's booting up, send a continuous stream of Ctrl+C characters to cancel booting and you'll be entered right into CFE.

From there, you can prod around CFE's features or load your own kernel using the [[CFE_Command_Line_Interface|command line interface]].

Connect to a modified router

2006-09-06T18:58:34Z

Justin:

Once we have the router powered up, connecting is as simple as plugging the [[Pictures|serial ports]] into a machine with the proper software to communicate over it (such as [http://www.columbia.edu/kermit/ Kermit]).

In our setup, once running Kermit on the external machine, we connected by typing in: 
{| border="0" cellspacing="0" cellpadding="0"
| <code>set line /dev/tty000</code>
|     
| to connect to the device talking to the router.
|-
| <code>set serial 8n1</code>
|     
| which is not really necessary since this is default.
|-
| <code>set speed 115200</code>
|     
| as given to us in the router specifications.
|-
|}

Once connected, you may need to press <code>Enter</code> to get a console from [[OpenWRT]].

Also, because the goal is to upload custom kernels to the router, it would be a good idea to connect the router to your network by wiring it up via one of the numbered LAN ports on the back of the router (NOT the Internet/WAN port).

Connect to a modified router

2006-09-06T18:41:46Z

Justin:

Once we have the router powered up, connecting is as simple as plugging the [[Pictures|serial ports]] into a machine with the proper software to communicate over it (such as [http://www.columbia.edu/kermit/ Kermit]).

In our setup, once running Kermit on the external machine, we connected by typing in: 
<code>set line /dev/tty000</code> to connect to the device talking to the router. 
<code>set serial 8n1</code> which is not really necessary since this is default. 
<code>set speed 115200</code> as given to us in the router specifications.

Once connected, you may need to press <code>Enter</code> to get a console from [[OpenWRT]].

Also, because the goal is to upload custom kernels to the router, it would be a good idea to connect the router to your network by wiring it up via one of the numbered LAN ports on the back of the router (NOT the Internet/WAN port).

Connect to a modified router

2006-09-06T18:40:10Z

Justin:

Once we have the router powered up, connecting is as simple as plugging the [[Pictures|serial ports]] into a machine with the proper software to communicate over it (such as [http://www.columbia.edu/kermit/ Kermit]).

In our setup, once running Kermit on the external machine, we connected by typing in:
<code>set line /dev/tty000</code> to connect to the device talking to the router.
<code>set serial 8n1</code> which is not really necessary since this is default.
<code>set speed 115200</code> as given to us in the router specifications.

Once connected, you may need to press <code>Enter</code> to get a console from [[OpenWRT]].

Also, because the goal is to upload custom kernels to the router, it would be a good idea to connect the router to your network by wiring it up via one of the numbered LAN ports on the back of the router (NOT the Internet/WAN port).

Wiring

2006-09-06T18:09:22Z

Justin:

[[Image:Embedsysdiag.png]]

* The diagram on the left represents the UART head on the main board of the router. The left pins (2,6,4,8,10) represent the data that is sent and received from the first serial port, the right pins (1,5,3,7,9) the second serial port.

* The diagram in the middle represents the [[Chips|MAX233A transceiver]] needed to convert the voltage used to transmit signals in the router (3.3V) to the RS-232 standard signals to send over the serial port.

* The diagrams on the rights represent two standard DB9F serial ports wired to be DCEs.

Please note that the diagrams do NOT represent actual placement of the pins on the hardware, which may have been moved to simplify the diagram.

Wiring

2006-09-06T18:04:26Z

Justin:

[[Image:Embedsysdiag.png]]

The diagram on the left represents the UART head on the main board of the router. The left pins (2,6,4,8,10) represent the data that is sent and received from the first serial port, the right pins (1,5,3,7,9) the second serial port.

The diagram in the middle represents the MAX233A transceiver needed to convert the voltage used to transmit signals in the router (3.3V) to the RS-232 standard signals to send over the serial port.

The diagrams on the rights represent two standard DB9F serial ports wired to be DCEs.

Please note that the diagrams do NOT represent actual placement of the pins on the hardware, which may have been moved to simplify the diagram.

Wiring

2006-08-28T06:06:56Z

Justin:

[[Image:Embedsysdiag.png]]

The diagram on the left represents the UART head on the main board of the router. The left pins (2,6,4,8,10) represent the data that is sent and received from the first serial port, the right pins (1,5,3,7,9) the second serial port.

The diagram in the middle represents the MAX233A transceiver needed to convert the voltage used to transmit signals in the router (3.3V) to the standed 5V signals to send over the serial port.

The diagrams on the rights represent two standard DB9F serial ports wired to be DCEs.

Please note that the diagrams do NOT represent actual placement of the pins on the hardware, which may have been moved to simplify the diagram.

Wiring

2006-08-28T06:06:08Z

Justin:

[[Image:Embedsysdiag.png]]

The diagram on the left represents the UART head on the main board of the router. The left pins (2,6,4,8,10) represent the data that is sent and received from the first serial port, the right pins (1,5,3,7,9) the second serial port.

The diagram in the middle represents the MAX233A transceiver needed to convert the voltage used to transmit signals in the router to the standed 5V signals to send over the serial port.

The diagrams on the rights represent two standard DB9F serial ports wired to be DCEs.

Please note that the diagrams do NOT represent actual placement of the pins on the hardware, which may have been moved to simplify the diagram.

Wiring

2006-08-28T06:03:51Z

Justin:

[[Image:Embedsysdiag.png]]

The diagram on the left represents the UART head on the main board of the router. The left pins (2,4,6,8,10) represent the data that is sent and received from the first serial port, the right pins (1,3,5,7,9) the second serial port.

The diagram in the middle represents the MAX233A transceiver needed to convert the voltage used to transmit signals in the router to the standed 5V signals to send over the serial port.

The diagram on the left represents standard DB9F serial ports wired to be DCEs.

Wiring

2006-08-28T05:54:21Z

Justin:

[[Image:Embedsysdiag.png]]

File:Embedsysdiag.png

2006-08-28T05:53:08Z

Justin: The wiring diagram of the serial ports we added.

The wiring diagram of the serial ports we added.