302 lines
		
	
	
		
			9.0 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			302 lines
		
	
	
		
			9.0 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
The Intel Assabet (SA-1110 evaluation) board
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============================================
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Please see:
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http://developer.intel.com/design/strong/quicklist/eval-plat/sa-1110.htm
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http://developer.intel.com/design/strong/guides/278278.htm
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Also some notes from John G Dorsey <jd5q@andrew.cmu.edu>:
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http://www.cs.cmu.edu/~wearable/software/assabet.html
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Building the kernel
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-------------------
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To build the kernel with current defaults:
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	make assabet_config
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	make oldconfig
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	make zImage
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The resulting kernel image should be available in linux/arch/arm/boot/zImage.
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Installing a bootloader
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-----------------------
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A couple of bootloaders able to boot Linux on Assabet are available:
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BLOB (http://www.lartmaker.nl/lartware/blob/)
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   BLOB is a bootloader used within the LART project.  Some contributed
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   patches were merged into BLOB to add support for Assabet.
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Compaq's Bootldr + John Dorsey's patch for Assabet support
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(http://www.handhelds.org/Compaq/bootldr.html)
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(http://www.wearablegroup.org/software/bootldr/)
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   Bootldr is the bootloader developed by Compaq for the iPAQ Pocket PC.
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   John Dorsey has produced add-on patches to add support for Assabet and
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   the JFFS filesystem.
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RedBoot (http://sources.redhat.com/redboot/)
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   RedBoot is a bootloader developed by Red Hat based on the eCos RTOS
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   hardware abstraction layer.  It supports Assabet amongst many other
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   hardware platforms.
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RedBoot is currently the recommended choice since it's the only one to have
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networking support, and is the most actively maintained.
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Brief examples on how to boot Linux with RedBoot are shown below.  But first
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you need to have RedBoot installed in your flash memory.  A known to work
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precompiled RedBoot binary is available from the following location:
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ftp://ftp.netwinder.org/users/n/nico/
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ftp://ftp.arm.linux.org.uk/pub/linux/arm/people/nico/
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ftp://ftp.handhelds.org/pub/linux/arm/sa-1100-patches/
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Look for redboot-assabet*.tgz.  Some installation infos are provided in
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redboot-assabet*.txt.
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Initial RedBoot configuration
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-----------------------------
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The commands used here are explained in The RedBoot User's Guide available
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on-line at http://sources.redhat.com/ecos/docs-latest/redboot/redboot.html.
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Please refer to it for explanations.
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If you have a CF network card (my Assabet kit contained a CF+ LP-E from
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Socket Communications Inc.), you should strongly consider using it for TFTP
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file transfers.  You must insert it before RedBoot runs since it can't detect
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it dynamically.
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To initialize the flash directory:
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	fis init -f
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To initialize the non-volatile settings, like whether you want to use BOOTP or
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a static IP address, etc, use this command:
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	fconfig -i
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Writing a kernel image into flash
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---------------------------------
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First, the kernel image must be loaded into RAM.  If you have the zImage file
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available on a TFTP server:
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	load zImage -r -b 0x100000
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If you rather want to use Y-Modem upload over the serial port:
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	load -m ymodem -r -b 0x100000
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To write it to flash:
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	fis create "Linux kernel" -b 0x100000 -l 0xc0000
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Booting the kernel
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------------------
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The kernel still requires a filesystem to boot.  A ramdisk image can be loaded
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as follows:
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	load ramdisk_image.gz -r -b 0x800000
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Again, Y-Modem upload can be used instead of TFTP by replacing the file name
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by '-y ymodem'.
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Now the kernel can be retrieved from flash like this:
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	fis load "Linux kernel"
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or loaded as described previously.  To boot the kernel:
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	exec -b 0x100000 -l 0xc0000
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The ramdisk image could be stored into flash as well, but there are better
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solutions for on-flash filesystems as mentioned below.
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Using JFFS2
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-----------
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Using JFFS2 (the Second Journalling Flash File System) is probably the most
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convenient way to store a writable filesystem into flash.  JFFS2 is used in
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conjunction with the MTD layer which is responsible for low-level flash
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management.  More information on the Linux MTD can be found on-line at:
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http://www.linux-mtd.infradead.org/.  A JFFS howto with some infos about
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creating JFFS/JFFS2 images is available from the same site.
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For instance, a sample JFFS2 image can be retrieved from the same FTP sites
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mentioned below for the precompiled RedBoot image.
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To load this file:
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	load sample_img.jffs2 -r -b 0x100000
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The result should look like:
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RedBoot> load sample_img.jffs2 -r -b 0x100000
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Raw file loaded 0x00100000-0x00377424
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Now we must know the size of the unallocated flash:
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	fis free
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Result:
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RedBoot> fis free
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  0x500E0000 .. 0x503C0000
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The values above may be different depending on the size of the filesystem and
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the type of flash.  See their usage below as an example and take care of
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substituting yours appropriately.
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We must determine some values:
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size of unallocated flash:	0x503c0000 - 0x500e0000 = 0x2e0000
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size of the filesystem image:	0x00377424 - 0x00100000 = 0x277424
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We want to fit the filesystem image of course, but we also want to give it all
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the remaining flash space as well.  To write it:
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	fis unlock -f 0x500E0000 -l 0x2e0000
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	fis erase -f 0x500E0000 -l 0x2e0000
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	fis write -b 0x100000 -l 0x277424 -f 0x500E0000
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	fis create "JFFS2" -n -f 0x500E0000 -l 0x2e0000
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Now the filesystem is associated to a MTD "partition" once Linux has discovered
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what they are in the boot process.  From Redboot, the 'fis list' command
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displays them:
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RedBoot> fis list
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Name              FLASH addr  Mem addr    Length      Entry point
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RedBoot           0x50000000  0x50000000  0x00020000  0x00000000
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RedBoot config    0x503C0000  0x503C0000  0x00020000  0x00000000
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FIS directory     0x503E0000  0x503E0000  0x00020000  0x00000000
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Linux kernel      0x50020000  0x00100000  0x000C0000  0x00000000
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JFFS2             0x500E0000  0x500E0000  0x002E0000  0x00000000
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However Linux should display something like:
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SA1100 flash: probing 32-bit flash bus
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SA1100 flash: Found 2 x16 devices at 0x0 in 32-bit mode
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Using RedBoot partition definition
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Creating 5 MTD partitions on "SA1100 flash":
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0x00000000-0x00020000 : "RedBoot"
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0x00020000-0x000e0000 : "Linux kernel"
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0x000e0000-0x003c0000 : "JFFS2"
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0x003c0000-0x003e0000 : "RedBoot config"
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0x003e0000-0x00400000 : "FIS directory"
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What's important here is the position of the partition we are interested in,
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which is the third one.  Within Linux, this correspond to /dev/mtdblock2.
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Therefore to boot Linux with the kernel and its root filesystem in flash, we
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need this RedBoot command:
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	fis load "Linux kernel"
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	exec -b 0x100000 -l 0xc0000 -c "root=/dev/mtdblock2"
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Of course other filesystems than JFFS might be used, like cramfs for example.
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You might want to boot with a root filesystem over NFS, etc.  It is also
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possible, and sometimes more convenient, to flash a filesystem directly from
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within Linux while booted from a ramdisk or NFS.  The Linux MTD repository has
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many tools to deal with flash memory as well, to erase it for example.  JFFS2
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can then be mounted directly on a freshly erased partition and files can be
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copied over directly.  Etc...
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RedBoot scripting
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-----------------
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All the commands above aren't so useful if they have to be typed in every
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time the Assabet is rebooted.  Therefore it's possible to automatize the boot
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process using RedBoot's scripting capability.
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For example, I use this to boot Linux with both the kernel and the ramdisk
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images retrieved from a TFTP server on the network:
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RedBoot> fconfig
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Run script at boot: false true
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Boot script:
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Enter script, terminate with empty line
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>> load zImage -r -b 0x100000
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>> load ramdisk_ks.gz -r -b 0x800000
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>> exec -b 0x100000 -l 0xc0000
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>>
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Boot script timeout (1000ms resolution): 3
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Use BOOTP for network configuration: true
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GDB connection port: 9000
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Network debug at boot time: false
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Update RedBoot non-volatile configuration - are you sure (y/n)? y
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Then, rebooting the Assabet is just a matter of waiting for the login prompt.
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Nicolas Pitre
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nico@fluxnic.net
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June 12, 2001
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Status of peripherals in -rmk tree (updated 14/10/2001)
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-------------------------------------------------------
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Assabet:
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 Serial ports:
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  Radio:		TX, RX, CTS, DSR, DCD, RI
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   PM:			Not tested.
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  COM:			TX, RX, CTS, DSR, DCD, RTS, DTR, PM
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   PM:			Not tested.
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  I2C:			Implemented, not fully tested.
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  L3:			Fully tested, pass.
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   PM:			Not tested.
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 Video:
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  LCD:			Fully tested.  PM
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			(LCD doesn't like being blanked with
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			 neponset connected)
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  Video out:		Not fully
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 Audio:
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  UDA1341:
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   Playback:		Fully tested, pass.
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   Record:		Implemented, not tested.
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   PM:			Not tested.
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  UCB1200:
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   Audio play:		Implemented, not heavily tested.
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   Audio rec:		Implemented, not heavily tested.
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   Telco audio play:	Implemented, not heavily tested.
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   Telco audio rec:	Implemented, not heavily tested.
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   POTS control:	No
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   Touchscreen:		Yes
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   PM:			Not tested.
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 Other:
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  PCMCIA:
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   LPE:			Fully tested, pass.
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  USB:			No
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  IRDA:
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   SIR:			Fully tested, pass.
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   FIR:			Fully tested, pass.
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   PM:			Not tested.
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Neponset:
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 Serial ports:
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  COM1,2:	TX, RX, CTS, DSR, DCD, RTS, DTR
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   PM:			Not tested.
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  USB:			Implemented, not heavily tested.
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  PCMCIA:		Implemented, not heavily tested.
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   PM:			Not tested.
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  CF:			Implemented, not heavily tested.
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   PM:			Not tested.
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More stuff can be found in the -np (Nicolas Pitre's) tree.
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