Re: PCI Express and Memory mapped I/O! - Hardware & Devices Discussion Boards

The LPT port isn't rated to deliver that much current, you will need a driver circuit plus the voltage from the LPT port under higher current isn't 5 volts.

Elaine Rose | [Rose]

The tigress is here Big Grin | :-D

thanx

Hi,
Does anyone know if there are any adapters available to install a PCI-X 64bit (133MHz) card on a PCIex8 slot which runs at x4 bus speed?? I know that there are interchangeable adapters available to install boards of PCIe (x1,x2,x4,x8,x16). But since a PCI-X 64bit 133MHz runs at the same speed as PCIex4 speed, I wonder if there are any adapters of this kind... Unsure | :~

-Pavan

You're somewhat confused on terminology at a minimum. The PCIe bus runs at a flat 100hmz, 1x, 2x, etc refer to how wide the bus is, a 1x PCIe card runs at the same speed as a 16x card, it just has higher bandwidth. That said, while a PCIe4x bus might have the same bandwidth as a PCIX133-64 bus (I'm taking your word for it), the signaling details are different, at a minimum 4 PCI-X 64bit words would need converted into 3 PCIe words before being sent onto the PCIe bus. This would require a processor of some sort to do the conversions in near realtime, and would likely still result in some degree of increased bus latency. You'd also have the problem of the card in the adaptor being raised higher than the other cards and not being able to screw into the backplate properly, so I very much doubt any such device would exist.

--
Rules of thumb should not be taken for the whole hand.

Hi guys,
Has anyone worked with Garmin GPS_18 receiver before?!
I want to use that product to get GPS data in a NMEA format and proccess it on a PIC microchip which supports RS-232 interface and I'm confused between two types of that GPS receiver the one with a cigarette lighter adapter and DB-9 serial interface and the other which has bare wires(LVC). which one shall I use and why?! Confused | :confused:

Waiting to hear from you all. Roll eyes | :rolleyes:

Thanks

Read the specifications[^] and pick the one that fits your requirements. Do you need the PPS signal available on the LVC model? Do you have a 12V (8-30V) supply that the PC model needs?

Hi,

I'm working with a PCI Express device. I'm planning to let it "DMA" (bus master) write the memory. I'm using a memaccess library from entechtaiwan. This lets me peek and poke memory addresses. When i peek, a pci request read sequence is initiated, when i poke a pci request write sequence is initiated.

Can anyone help me with the following things:

- when i peek a shared memory address, a pci express sequence is initiated. very nice, but what if The Device has "DMA"ed the memory space, and i just want to know the values?

- and the other way around. How to write this shared memory for the PCI bus master to "DMA" read it's values, without the pci express sequence to be initiated?

any ideas, sugestions or laughter would be appriciated... I'd like to understand the matter, before spending a lot of time on it and then discover i can start over again..

Thanks in advance,

Arjan van Heusden.

DMA is the ability for the device to take control of the system's memory bus (become the 'bus master') and write directly to system memory locations without the need for software running on the system's host processor.

This is really a logical 'bus' concept dating from the time when everything was directly connected to the (single) processor's address and data bus pins. Normally the processor was 'bus master' - it emitted the necessary voltages to drive the address and data buses. For another device to write to or read from the system memory (or any other device connected to the memory buses), a Direct Memory Access [DMA], it had to ask the processor to put its bus drivers into high-impedance mode, so that it was not interfering, electrically, with the buses. When finished, the device then relinquishes its master status.

On a modern system there are many, many different buses which run at different speeds and have different electrical characteristics. To cross between these different buses, there are different bus controllers. On Intel processor-based systems, the key one for PCI Express operations is the Memory Controller Hub, which connects the processors' Front Side Bus to the memory buses (now normally two), the PCI Express channels, and the Inter-Hub Transport which connects to the I/O Controller Hub (on Intel chipsets). On AMD processor-based systems, the memory buses connect directly to the processor, while the PCI Express channels are connected to a PCI Express controller which connects to the processor(s) over a HyperTransport link.

Any operations that involve reading from or writing to a PCI Express device will need a PCI Express read or write sequence, whether driven by the processor or by the device itself. The PCI Express transaction is the read or write operation.

To get the results of a DMA write operation (i.e. the device writes to memory), you simply need to read from the physical memory addresses that the DMA operation wrote to. Conversely, to control a DMA read operation, you need to write the data to be transferred to a particular physical memory location (or locations), and program the device to perform the DMA from those locations. Actually, you can normally program the device to transfer the data from locations that already contain the correct data.

Stability. What an interesting concept. -- Chris Maunder

:|Hi,
can any one give me a win32 api and also a control or library that can get the NEC MAC address from the Hardware itself not from the registry. it will be good if it can be used in C#.

May god give u good health and knowledge.

Reader Man San wrote:
library that can get the NEC MAC address from the Hardware itself not from the registry.

Have you taken a look at these articles?
http://www.codeproject.com/cs/internet/host_info_within_network.asp[^]

http://www.codeproject.com/tools/MacIdChanger.asp[^]

I'd love to help, but unfortunatley I have prior commitments monitoring the length of my grass. :Andrew Bleakley:

i read the articles but the code in them gets them from the registry -and that has a possibility of bieng changed- not from the NIC Hardware, which is what i want.

but
Thanks for reply...;P

May god give u good health and knowledge.

Reader Man San wrote:
gets them from the registry

Little bit of hunting around GetAdaptersInfo, seems to be the api call. Still havnet found where it gets its info from.

http://www.codeproject.com/internet/IPHelper.asp[^]

I suppose the only way to know for sure would be to send a packet to local loop back and interrogate it for the MAC.

I'd love to help, but unfortunatley I have prior commitments monitoring the length of my grass. :Andrew Bleakley:

Thanks,
i will need to check it by using programs that change the registry's saved MAC Address.
Laugh | :laugh:

___________________________________________
May god give u good health and knowledge.

Hmm, how about ShellExecuteEx() with an ipconfig /all command piped into t file that your code then opens and reads the MAC address from.

Either that or write an upperlayer driver that has an IOCTL interface which can be opened by your app and sends the query MAC address IOD to the adapter it binds to.

Truth is the subjection of reality to an individuals perception

Thanks for the second idea, i thought about it but i am not good in hardware drivers, they are hard stuff for me. Laugh | :laugh:

___________________________________________
May god give u good health and knowledge.

I can give you source code for such a 'protocol' driver if you like.

I takes an IOCTL from an app that opens a particular adapter, than, there is a generic OID handling IOCTL. YOu can set/request any OID with this.

It is a complete project, but you will need a DDK, preferably the 2003 server DDK. It has an inf file for installation too.

Truth is the subjection of reality to an individuals perception

Recently, my PC at work has decided that every 5 minutes or so it will beep several dozen times. The beeps are not evenly spaced, and so I wondered if my PC is trying to send a morse code distress message! Strangely, a colleague's PC did exactly the same about a month ago, so he disconnected the speaker. We never found out what was causing it. I've no idea whether this is a hardware thing, or an OS thing (we're both on Win XP). I don't know where to start looking.

Does anyone have any idea what it could be? Has anyone had the same thing? Is anyone fluent in morse code, and translate the PC's distress call?

"The way of a fool seems right to him, but a wise man listens to advice" - Proverbs 12:15 (NIV)

3 possibilities...

1) The fan and heatsink sitting on your CPU is so clogged that the processor is starting to overheat. Or some other hardware problem, for which you'll have to consult the manufacturer of the machine to find out.

2) You have a virus on your machine.

3) Someone has written and installed a little app on your machines and is in the corner laughing at you, seeing how long it will take before you figure it out.

Dave Kreskowiak
Microsoft MVP - Visual Basic

Thanks for the ideas Dave. My thoughts on those:

1. That was my first thought (which is why I posted on the Hardware board), but as far as I can see the fan is OK, processor temp OK. I would kind of expected the occasional freeze if this was the case anyway. Still, jury's still out on other hardware problems. Bit of a coincidence that a colleagues PC did the same though.

2. Mmm, thought of that too. In some ways more likely, as that would explain why my PC was not the only one, but our AV is generally good - though I know nothing's 100% effective - so we would usually consider ourselves to be (nominally) "virus-free"

3. No-one laughs at me and gets away with it. Do you hear me? NO-ONE! Poke tongue | ;-P

"The way of a fool seems right to him, but a wise man listens to advice" - Proverbs 12:15 (NIV)

Yeah, I've got some machines aorund here that run fine, right up until the processor melts internally. The heatsink fins get so caked with dirt, in places that you can't see under the fan, that you have to take a can of air to them. Vaccuming them out doesn't do any good.

As for the prank, come on! You can't tell me that you haven't thought of doing this yourself! I did it with a small remote control "fart noise" maker. Taped it to the back of this girls machine and, err, "let 'em rip!" Not very often, but just enough to drive her nuts for about 3 weeks! Poke tongue | ;-P

Dave Kreskowiak
Microsoft MVP - Visual Basic

Found it: my PS2 mouse is bust. I've switched it for a USB mouse, and I no longer have the beeps. I arrived at that because it started making my mouse pointer jump, and doing a scroll and a right-click, every time a system beep happened.

Dave Kreskowiak wrote:
You can't tell me that you haven't thought of doing this yourself!

Yes, I have, but nobody's that much fun around here! In a previous company we used to do that kind of thing all the time. Ah, those were the days...

"The way of a fool seems right to him, but a wise man listens to advice" - Proverbs 12:15 (NIV)

Paul S. Vickery wrote:
Recently, my PC at work has decided that every 5 minutes or so it will beep several dozen times.

While not entirely similar, the only time I have had the little speaker go beeping like that was when I was doing a full recompile or something else processor intensive. Turns out the thermal paste was bad. Cleaned the old stuff off and replaced no noise since then. Strange don’t know if checking that will help or not but certainly worth a shot (I was seeing elevated temps on the CPU).

I'd love to help, but unfortunatley I have prior commitments monitoring the length of my grass. :Andrew Bleakley:

I'm in the last year in computer scince faculty and i'm asking Can I Make an MP3 Palyer Support RM (real Media) . using a specific programming language or it is related to the hard ware itself

Thanks.

First you'll need to find out what the hardware environment of hte player is and how to reprogram it. Try searching for guides on how to hack mp3 players to find ones that someone else has already figured out how to reprogram. THis will likley consist of loading a minimalist linux distro of some sort, hopefully with a audiuplayer that works with the platform.

Then you need to port/write a RM codec compatable with it. Search for real alternative, IIRC open source.

You'll need to repeat this for each mp3 player family you want to get RM working on.

Thank you very much

honored