Posted: Thu Aug 05, 2010 7:19 Post subject: Confirmation on chip selection for a "de-neuter" (
Hello, I recently aquired two WRT54G-v8 routers from a yard sale. And after doing some research I have decided to mod at least one of them. I'm skilled in the art of soldering/moding and could definetly make use of the extra functionality I would gain. what I don't know is the exact details of the v8 hardware, nor do I know what firmware mods (if any) will be required to make the new hardware work after it has been installed. So I have come to those who know these things
Here are links to the datasheets for the Stock/Old RAM as well as the New/upgrades
I have also uploaded the ziped PDF's as atachments to this post. Just incase the links suck.
To my eyes there is only one problem that may or may not pop up with the ram. theres a speed diffrence. The stock RAM *series* is capable of a max of 200Mhz, while the upgrade *series* can only do 166Mhz max. As for exact models... I don't know what the stock RAM runs at, it doesn't say on the chip and it's not in the wiki. but the new stuff is 143Mhz-70ns. It can prolly OC higher than that, so 166Mhz isn't out of the question. But 200 is probably too much. Other than that, I don't see a problem. 16MB as opposed to the 8MB stock is good. I would like to go to 32MB so it's just like a WRT54GS's v1-v3 with a faster CPU. But sorceing a chip like that is impossible, and I allready have four of the 16MB chips on hand, ready to go. Any thoughts so far?
As for the Flash, I have NO idea if it will work or not. There is a lot to consider. The old stuff as I'm sure you all know is 2MB. Well the new stuff is 8MB, A TON better. It's the right package and pinout. It uses the same word-or-byte structure as the old one. Bottem boot block capable. The same or better access time, same voltages. One thing i'm concerned about is that the new chip has an "Extended block" which can be "protected"... irreverseably of course (-.-). I don't know how the firmware will handle this. It's in the boot area when activated and if it some how gets used and locked, that would brick the thing. I also don't know if the "command interface" uses the exact same protocal. A glance at the tables says they look compatable. If there is anything I missed, plz point it out.
My last concern would be how to make the firmware recognise and use the new resorces. DD-WRT-VPN or mega *may* see the router model and decide not to work just because it wouldn't under stock conditions. Also, The Flash/Ram ratio is different. 16/8 dosn't exist in any of the routers that are on the WRT54G wiki. I figure this is likely not going to be a problem because It could just use the first 4MB and forget about the rest, but if it is a problem tell me and I'll cart up a diffrent one. I haven't got the Flash yet, It is a Digikey order yet to be commited to. The DigiKey part number is M29W640GB70NA6E-ND. If there is a better choice out there, let me know.
Any way, that about covers it. I look forward to your replys.
(P.S. Spellcheck in OpenOffice build:9502 is apparently broken? I did my best to do with out.)
Edit: Oops I F*%^ed up!!! I was going over it all and the math wasn't adding up. As it turns out I was wrong about the ram chip size, It actuly IS 32MB. The whole 16 bit bus messed with my head, sorry. But rather than hide my mistake under the rug I'll leave it be for right now with just this note. Dissreguard all the stuff about not being able to get a chip in that size and what ever else I said about it maybe not working because of the incorrect ratio. Thanks
Make sure that you have the extra address lines on the routers cicruit board, needed to address bigger chips.
The traces may be there and are either connected to the chip pads or ends just before the pads. If they end before then the pcb is prepared for bigger chips and the missing link between the trace and the pad is intended to be a 0 ohm surface mount resistor (electrically a jumper).
Compare the .pdf of the new and old chips to find out which the pins are. _________________ Kernel panic: Aiee, killing interrupt handler!
"Make sure that you have the extra address lines on the routers cicruit board, needed to address bigger chips."
Yeah, I figured as much. The RAM appears to have all the traces. Some of them are hidden Under the RAM chip and the CPU/MCU/DSP though. So there is no telling if every one of them is actaully going all the way to the pads or not. But I seriously doubt that they arn't connected. That would be kinda dumb. But if they are not, I don't see how I will be able to jumper them while the breaks are under the chips. It would be hard.
As for the Flash, It has the 0 Ohm SMT resistors. I was just going to bridge the newly needed ones with solder. One thing is i'm not exactly sure which ones to jump or not. Normaly you would just 2^X untill you get the capacity you want in bytes/words, then connect A0-AX numberd address lines (hope that made sence to everyone). The thing is, some of the address lines that should already be in use are jumped (linked as you put it), but some of them aren't? So... are they supposed to be shorts to the bus traces? Or tie downs-ups? For example, address pin A1 is open when it shouldn't be. It's the bottem left most pin and the bottem jumper. On the other hand, address pin A5 is shorted?!?! It is the first one from the bottem left thats been jumped. I would continuity test everything just to see whats going on. But my Fluke outputs 9v, which may or may not fry the bus drivers. If you know which ones I should jump I'm all ears?
Also, I was going over the brief for the Broadcom BCM5354. And it says that it's SDRAM controller only goes up to 120Mhz. So that answers the question of weither or not the new ram can keep up. The brief also says that it suports DDR. Can I make use of that? Will that give me any significant performance improvements? Is it going to be hard to "activate" (for lack of a better word), or will it just be automatic? I guess I shouldn't bother as I already have some good replacement's. Besides It's the size thats the issue here, not the speed right? Meh... it was just a passing thought any way.
On another note, Do I absolutely need jtag to do this mod? The header holes look like they were deliberatly exposed to some slightly corrosive/oxidizing substance. Probably with the intent to make the copper not take to solder. Should be an easy fix but there is also some thing else. There is silk screening in the jtag area were there's supossed be parts and they are missing. Looks like a few resistors, capacitors, and a SMT transistor. They look like they might be involved but they may not be needed. I may be able to fix it some how. However, I would still like to get the wholeflash.xxx a diffrent way if possible or even needed. The one unit already has DD-WRT micro: build 13064 flashed to it, if that makes a diffrence. I didn't do the flash my self, thats just the way I got it. So I don't have the origional firmware backed up anywere. The other router does have the original firmware on it still so I do have access to a stock v8 wholeflash.
So, I've got some crappy pictures for you (LOL). So you can see the traces for your self. You can also kinda see the jtag header and the parts that are missing. It's hard to tell but the plating looks kinda like its been "powder coated". I'm to lazy to dig for my photobucket user name and password right now. So i've just uploaded them as attachments. I tried to crop them down, but the forum still insisted on makeing them HUGE. Sorry bout that. When I get some fresh bateries i'll take some good before/durring/after pics and try to document every thing I do for you all if you want me to.
OK, so shortly after I made my last post I was board out of my mind. So I decided to give that RAM a try and see what happens. It worked fine, but it is only saying that there is 16MB!?. Could some one confirm the size of the new chip so I can stop second guessing my self? Was I wrong about the size? No, it has to be some problem with DD-WRT micro or it's settings right? It COULD be caused by the 24th address pin, and just that pin being disconnected. But that would be a very lucky mistake. It's far more likely that the firmware just needs to be reconfigured correct?
Any way, I took pictures through out the whole process so you too can join in on the glory of reworking with cheep tools. There is a picture of all the tools I used as well as a screen shot of the GUI showing the model and the fact that it actually has 16MB of RAM. I gave it some thought, and I'm just going to upload them as a .RAR to avoid 9^999 miles of huge pictures. It is all compressed so DL'ing it should be no problem for most. I hope this isn't a problem with anyone?
OK, so shortly after I made my last post I was board out of my mind. So I decided to give that RAM a try and see what happens. It worked fine, but it is only saying that there is 16MB!?. Could some one confirm the size of the new chip so I can stop second guessing my self?
The ram chip is 32MByte but you have to change ram definition parameters in the cfe in order to see all of it.
Try writing them to nvram to start with and reboot the router to verify that they are right.
nvram set sdram_init=0x010b
nvram set sdram_config=0x0062
You can later on when you have replaced the flash chip use Tornado's eminent cfe for the WRT54G-TM, it already has the correct sdram settings since the TM is an 8MB/32MB router.
Edit: The replacement ram is not a DDR SDRAM which is the usual type for 32MB routers so the ram parameters above are wrong.
nvram set sdram_init=0x000a
nvram set sdram_config=0x0032
are the right ones for a 32MB SDR SDRAM. _________________ Kernel panic: Aiee, killing interrupt handler!