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--- projects:routers:netgear:wgt634u [2013/01/20 00:56] – [Free Software] admin
+++ projects:routers:netgear:wgt634u [2013/02/01 11:35] (current) – [JTAG software] admin
@@ Line 29: / Line 29: @@
 ==== JTAG on router ====
-Following text is from [[http://irgendwasistjaimmer.in-kiel.de/iwiji/index.php?/archives/23-How-to-flash-a-new-CFE-into-your-bricked-Netgear-WGT634U.html|this webpage]].
+Following text is from [[http://irgendwasistjaimmer.in-kiel.de/iwiji/index.php?/archives/23-How-to-flash-a-new-CFE-into-your-bricked-Netgear-WGT634U.html|this webpage]].\\ Once upon a time, when the WGT634U wasn't yet EOL'd, OpenWrt had a bug that caused the flash partition containing the CFE to be erased. As the CFE is the boot loader, you then had a paperweight.\\ There were rumors one of the two headers on the PCB was a JTAG port, but nobody found out how to utilize it.\\ \\ Some weeks ago I came across [[http://secure.dd-wrt.com/phpBB2/viewtopic.php?t=28947&postdays=0&postorder=asc&start=129|this forum post]] detailing how to populate the resistor pads to make JTAG work. That link also provides the image file which is to be flashed.\\ \\ My WGT634U is now resurrected, so how to repeat this?\\ \\ First, you need to populate the 2x7 header on the front side and the resistor pads on the backside. These resistor values worked for me:
-Once upon a time, when the WGT634U wasn't yet EOL'd, OpenWrt had a bug that caused the flash partition containing the CFE to be erased. As the CFE is the boot loader, you then had a paperweight.
-There were rumors one of the two headers on the PCB was a JTAG port, but nobody found out how to utilize it.
-Some weeks ago I came across [[http://secure.dd-wrt.com/phpBB2/viewtopic.php?t=28947&postdays=0&postorder=asc&start=129|this forum post]] detailing how to populate the resistor pads to make JTAG work. My WGT634U is now resurrected.
-How to repeat this?
-First, you need to populate the 2x7 header on the front side and the resistor pads on the backside. These resistor values worked for me:
 <code>
 R66 (pin 3) 10KΩ
@@ Line 45: / Line 37: @@
 R73 (pin 11) 33Ω
 </code>
+Information about the pinout on the wgt634u can be found [[http://wiki.openwrt.org/doc/hardware/port.jtag|here]]. It is assumed that the pin layout is MIPS EJTAG 2.6 compatible:
+<csv hdr_rows=1>
+function,pin,pin,function
+nTRST,1,2,GND
+TDI,3,4,GND
+TDO,5,6,GND
+TMS,7,8,GND
+TCK,9,10,GND
+nSRST,11,12,n/a
+n/a,13,14,Vcc
+</csv>
+A buffered cable such as the Wiggler requires an external Vcc voltage supply. The 14-pin header conveniently supplies this voltage on pin 14. The typical unbuffered cable, however, does not require an external voltage in order to function. Formally, the pin 14 is called VREF and used to indicate a JTAG signal levels: 5V, 3.3V or 2.5V. On the most devices this pin is tied to the device's Vcc and may be used to power a buffer IC chip (and to generate an appropriate levels as result). Note that the 12-pin JTAG header arrangement does not provide Vcc.
 ==== JTAG software ====
 In the openmoko wiki they tell how to use openocd with the Debug Board to flash the openmoko Freerunner gsm phone; but there's no information regarding MIPS devices like the WGT. I finally managed to do it using urjtag revision 1855 (current HEAD) from their svn.
@@ Line 64: / Line 67: @@
 </code>
-Then, you can finally flash your WGT:
+Then, you can finally flash your WGT. Download the [[http://www.auditeon.com/xyz/wgt634uCFE.bin|image wgt634uCFE.bin here]].
 <code bash>
 cable ft2232 vid=0x1457 pid=0x5118
@@ Line 74: / Line 77: @@
 </code>
+===== Links and information =====
+  * [[http://www.fccps.cz/download/adv/frr/spi/msi_spi.html]] Programming a flash chip in-circuit via the parallel port

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