Have not looked into it fully but I do know that you can set up MBM to send commands over the SMbus. :shrug: It's in the help file somewhere.

nicozeg
sorry, just chasing a good idea (also)

Murray13,

Thanks for the cable reference... I'll see if I can get that. :D

Capt._Foo_Foo,

The switch is a micro toggle PCB switch SPDT. Digikey part # 360-1012-ND

pHaestus,

MBM5 I believe supports these as most motherboards already have at least one similar to the 6655 onboard. The madhacker article I found though the MBM site under the "Extensions" tab.

pelle76,

Did you realize you have a spider in the middle of your circuit board? :dome:

leejsmith,

Outside the 48 states, the purchaser will be responsible for shipping. Shouldn't be much as small as this is. :D

yea it detects fine with mbm. will report temps with 1c res though. ic capable of 1/8c; just need to lower sampling rate and reclaim those bits...

//edit (underlined)

Yeah... I was a little suprised that the thing worked... ...I mean, thats a quite big "BUG". :eek:

Here's the new design fellas... The SMBus & Power will use a 6 pin connector. I suppose I could have made it five pin... but I wanted a key. :p

Let me know if this is to your liking... working on the 5566 now.

http://pages.sbcglobal.net/mmz-timel...youtRev1-1.jpg

MMZ did you check the Maxim guides to trace width? There's a pdf about improving accuracy w/ diode-based solutions on their site and they give some guidelines. With length so short (and with header there anyway) it shouldn't be a big deal but might be worth perusal. That 0.125C bit is a big deal though for some. I bought $100 MAX6655EVSYS purely because they had software that did 1/8C

And of course that software only works over parallel port using their SMBus to Parallel adapter...

Oh and I'd be good for 1 of each (soldered).

Could that be solved by joining grounds of both PCs?

In fact that happens through the power cable to the wall, but maybe a more direct path can be better.


Why stick to MBM if we can use Maxim software with the full resolution available :D

As I understand, your compatibility problems with win XP were more related to the paralell port interface used in the evsys.

Ouch I did't know that, That software is suposed to work with the Evkit which is the smbus only version of the Evsys.

Have you tried to use it directly attached to the smbus mobo header?

Yea see where it says MaxSMBus? That's their daughtercard... I'd be happy if it DID work though (no mobos with SMBus headers onboard atm can someone else check?)

The same PSU usually powers the MAX6655 and the test PC. That was the source of my weird data a couple weeks ago; PSU was going bad and was only supplying something like 4.4V to the MAX6655. Giving it juice within spec returned results to what previous testing had shown.

sounds like a good argument for NOT using the computer psu (in any case if the supply voltage is affecting the output)
pHaestus - any idea of the sensitivity ?
(is a STIFF 5V psu really necessary ?)

.pdf says 4.5-5.5 for VCC; no data for effect of VCC on temperature in specs but every other parameter is graphed.

I had some serious problems with that PSU though and AMD CPUs will stress the 5V rail. I guess a PC PSU that allows you to dial up the 5V (as measured by Vin on Maxim) would be the way to go if you wanted to monitor VCore at the same time. Thermaltaco sells some with potentiometers in a bay drive for adjusting power. Alas! If I only had a grothmeter (and a way to convert output current to a voltage I could read with maxim Vin...

Okay guyz... I think I got the dual 6655 done... WHEW! :eek:

Man that's a crowded board! Same basic layout as the other one with the temp probes in the same place with the same pin layout. The SMBus header and power headers are in the same place for consistancy.

I did include pins for the voltage probes and the additional address selectors. There is also a two pin header by itself for each of the OVERT pins (both OVERT pins in one two-pin header)

I'll have to make a sticker or something to mark the back of the board as there is no room for silkscreen work. :eek: :dome: :cry: :D

http://pages.sbcglobal.net/mmz-timel...(Dual5566).jpg

Let me know if you spot any obvious flaws before I go to prototyping. (probably next weekend)

Ok scratch my order for one of the 1668s; would like 2x these. How much different in price for dual boards?

About $10 more each for the parts cost increase the overall soldering work is about the same.

So looking at about $50 now? I will probably back down to one and save the money for other activities now that I think about it.

I haven't actually run the numbers pHaestus.... lemme narrow it down. I MAY be able to cut it lower. But I need to get the actual prices from DigiKey.

I'll let y'all know. :D

Problem there is ground float. The return currents times the wiring resistance means that 'ground' at the little IC board will not be the same as 'ground' at the CPU socket of the target PC. You could try to tie the ground of the two PC together, but you have the risk that some of the current supplied by PSU-A will want to return via PSU-B, and switcher power supplies don't like that.

In my experiments, I used an optically isolated SMBus. The IC board was powered by the target PC and grounded at the socket, but the control and logging was done on the electrically isolated second PC.

Perhaps our good buddy MMZ_TimeLord could make a small, separate SMBus isolation board? :D

pH, the Grothometer is pretty much useless until/unless I get an o-scope to calibrate it. And with the ongoing underemployment, that might be a while.

Would... (but already did)
Thx Star :)

this keeps getting better and better

Groth
I understand the need/benefit of the optical isolation (std in other things),
but how does that resolve the floating ground issue, or is it then moot ?

Care to guess how much it'd cost to ship a kit transatlantic timelord?

Groth,


That circuit looks pretty easy... can you give me a part number on the optical isloators.


Bill,

moot (I think... Groth verify :D )

By isolating the two busses optically, you are never actually connecting the two devices to the same power supply and can power the measureing devices on a separate PSU without the floating ground issue.

Butcher,

It could fit in a letter sized evelope or one of those larger letter bubble pack ones...

How much?

count me in for one unsoldered

I'd get one or two soldered

Spoon fed, eh? :D

The isolation is of course only an issue if you want to measure the voltages of a target system from another PC, the temperature reading circuitry is internally isolated.

Powering the reader IC from the target computer eliminates the ground float related to current return though the PSU power cords, plug, and some wall wiring (if you don't have your two computers plugged into the the same socket). You still have the potential for float/noise from things like the ATX connector, long strings of molex connectors, wimpy power planes, etc.

My prime concern was the CPU power. Accurate measurement of Vcore was more important that accuracy of 12V, or Vdimm, or any others. So I grounded the reader IC at the back of the CPU socket. It's ground will float relative to others' due to the 60+ amps the CPU can dump into the ground plane, but it's ground will match the CPU's ground. Not allowing for that float overestimates Vcore and CPU power.

So, yeah, the bus optoisolator resolves between-computer ground float/noise. And it moots local float/noise if you ground it to match your measurement of interest.

MMZ_TimeLord, I used Digikey part number PS8701-ND (I like SMD), but TLP550-ND would work just as well. I'm sure there are others, they just have to be faster than around a microsecond, to keep the bus from timing out.

spoon fed ? LOL
you bet (Thanks), I last studied electronics in the Navy in '63
- a bit different then, always been catch-up since - topic by topic

You can put me down for a 6655!!!