[time-nuts] PCI-E Serial Card For Windows NTP?
kb8tq at n1k.org
Thu Jun 25 18:57:56 EDT 2015
I have had no problem with a variety of PIC serial cards. I’ve got a few from maybe six different outfits. They run up to at least 115.2K baud. The multi port versions will do that on all ports at one time. They are far more dependable than their USB counterparts. I’ve run them under XP, Vista, Win 7, Linux and Free BSD. They don’t seen to have problems under either the 32 or 64 bit versions.
I would get it from a vendor who’s name you recognize. Not so much because it will be a better part. Only so that tracking down the Windows 10 drivers (or which ever version we all will be on) is a bit easier.
> On Jun 25, 2015, at 1:41 AM, Ed Armstrong <eds_equipment at verizon.net> wrote:
> Hi, I'm still pursuing setting up a fairly accurate NTP server connected to my Nortel/Trimble GPSTM. So far I've been playing with a Raspberry Pi 2, and have made fairly good progress using a bunch of tweaks detailed by another member of this list. However, it has been noted that the Raspberry Pi has some limitations for this purpose, not the least of which is having a USB connected ethernet port. Consequently I am also looking at some other options.
> The GPSTM and the Raspberry Pi will be sharing a shelf with my server, which is running a Core i7-3770 @ 3.4Ghz and a 64-bit version of Windows 7 Ultimate. This machine is typically running at about 10 to 20% CPU usage, and it is extremely rare for the CPU usage to exceed 50%. It is also equipped with an Intel gigabit ethernet port, connected by PCI express bus. I expect this may perform a little better than the pi's 100Mb card which is connected by USB. I also suspect that the i7 will do a bit better in terms of interrupt latency.
> There is a driver available for Windows 7 which allows use of the DCD pin on a serial port for PPS. Sadly, this machines motherboard does not have a serial port, nor a parallel port. Not even a header for one. And this leads to my question.
> I am considering adding a PCI express serial port card to this machine, but I don't know how well they perform for this application. There are quite a few different cards available, ranging in cost from under $10 to over $50. I am wondering how well these cards work for this application in general, and if there are some cards which will work well and some which will work poorly or not at all. And of course, if there is major variation between the cards, I would like to know how to pick one which will work well. I do have a little experience with parallel port add on cards, as I run a CNC milling machine which uses the parallel port to control the machine. Most of the parallel add-on card you can buy work fine for a printer, but will not work at all for sending pulses to the CNC machine. Only a very few cards are full function parallel ports, and they are pricey. Before I waste $8 on a cheap serial port card, I want to make sure I'm not looking at the same situation. If it matters, I'm planning on a dual-port card.
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