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WirelessNetworking

It appears that simple and affordable wireless networking may now be possible with the AVR32 and other embedded Linux systems, without signing a non-disclosure agreement, or waiting while the sales and support people ignore you (unless you are a Tier 1 customer). The latest release candidate of the Linux kernel (2.6.24-rc3 at the time of this writing) contains drivers for the Marvell 88W8385 wireless chipset along with a CompactFlash, USB, and SDIO stack for it.

The following options need to be enabled in the kernel configuration:

Networking->Wireless->802.11

Device Drivers->Network Device Support->Wireless LAN->Marvell Libertas

the required kernel modules are called libertas.ko, libertas_sdio.ko, libertas_cs.ko, firmware_class.ko, ieee80211, and ieee80211_crypt.

Also required is the firmware binary blobs for the Marvell chip.

Firmware can be loaded by a simple hotplug script:

#!/bin/sh

# Simple hotplug script sample:
#
# Both $DEVPATH and $FIRMWARE are already provided in the environment.

# check /tmp/hotplug.set.xxx for script debugging purposes
set > /tmp/hotplug.set.$$

HOTPLUG_FW_DIR=/lib/firmware/

echo 1 > /sys/$DEVPATH/loading
cat $HOTPLUG_FW_DIR/$FIRMWARE > /sys/$DEVPATH/data
echo 0 > /sys/$DEVPATH/loading

# To cancel the load in case of error:
#
#       echo -1 > /sys/$DEVPATH/loading
#
-----------------------------

Just save the script above as /sbin/fwloader and enable it like this:

echo /sbin/fwloader > /proc/sys/kernel/hotplug

Wireless Chipset Module:

Gumstix's Marvell 88W8385 based WiFi module. It's a real deal at $40.00 + shipping. It also comes with an antenna. It is manufactured by Wistron NeWeb Corporation, and is called the DRCM81. Here is the datasheet. It is not possible to use the SPI or SDIO interface with the Gumstix module because the SDIO_D0 and SPI_CS are not available on the connector. Here is another possible source of WiFi modules.

The 88W8385 chip supports compact flash, SPI, and SDIO interfacing. Here's another datasheet for another similar module using the 88W8385.

* Gumstix module pin arrangement and compact flash connections:
pin_arrange.jpg cf_pinout.jpg

Eagle schematic from gumstix

Connectors:

The mating 50 position Molex connector 54722-0507-C and it's datasheet

For prototyping, an SMD to through hole prototyping adapter will also be helpful.

Firmware

Apparently the story goes like this, Marvell licensed the firmware from a third party for this chip, so they don't own it. Since they don't own it they can't or won't redistribute it. But somehow the folks at gumstix have a copy to use with their products. Anyway, the links below contain what I have found. This firmware may or may not work. I hope to test it within a week or so, when my prototyping board is delivered.

* sd8385_firmware.tar.bz2: Firmware for cf8385_B0/W8015

* sd8385_firmware2.tar.bz2: Another possible firmware set

* extract_fw.c: Simple C program to extract firmware from source code

* WLAN_Firmware_Spec_v5_1.pdf: SD8385 firmware specs

* DRCM-81_g_eModule_1.0_0324.pdf: Wistron DRCM81 Wifi module datasheet

  File Size Date By Actions
pdf DRCM-81_g_eModule_1.0_0324.pdf
Wistron DRCM81 Wifi module datasheet
346.7 K 2008-02-27 - 11:41 JohnVoltz props, move
pdf WLAN_Firmware_Spec_v5.1_-_MV-S103752-00.pdf
SD8385 firmware guide
1622.3 K 2008-02-13 - 01:42 JohnVoltz props, move
pdf WLAN_Firmware_Spec_v5_1.pdf
SD8385 firmware specs
1622.3 K 2008-02-13 - 01:46 JohnVoltz props, move
jpg cf_pinout.jpg
Gumstix module, compact flash connections
30.2 K 2008-02-10 - 18:49 JohnVoltz props, move
c extract_fw.c
Simple C program to extract firmware from source code
0.4 K 2008-01-20 - 03:49 JohnVoltz props, move
jpg pin_arrange.jpg
Gumstix module pin arrangement
7.0 K 2008-02-09 - 17:25 JohnVoltz props, move
else sd8385_firmware.tar.bz2
Firmware for cf8385_B0/W8015
66.2 K 2008-01-20 - 03:46 JohnVoltz props, move
else sd8385_firmware2.tar.bz2
Another possible firmware set
65.0 K 2008-02-10 - 18:26 JohnVoltz props, move
r10 - 2008-07-24 - 14:57:26 - JohnVoltz
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