Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

>The normal RS-232 level shifter chip includes an inverter.  (No good reason, 
>just historical, but with a long history.)

>I can't understand the schematic on the part Gary suggested.  I'd use 
>something like this:
>  https://www.sparkfun.com/products/11189

Hal,

Thanks, this had me look closer at the outputs and not all RS232 chip breakout 
boards shift all signals, it seems to be 4-6 lines at most.
I've seen some MAX3232 (RS232 to TTL) converters, but the better ones only 
shift Rx, Tx, CTS, RTS, VCC and GND.

If I read what was suggested here earlier correctly, I need DCD for the PPS 
signal and Rx, Tx for NMEA.
I plan to use this with pfsense/gpsd which lets you choose between rising and 
falling edge for PPS signal processing.

I'll go ahead and order https://www.sparkfun.com/products/11189 as it appears 
to do all RS232 signals and can handle voltages > 5V.


Thank you all again!
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Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

>The signals on the DB9 connector are at RS232 levels, your GPS module is 
>likely 3V3 CMOS, you will need to make a level translator if you wish to use a 
>standard PC >RS232 serial port.

Would this do the trick? - 
http://www.banggood.com/8-Channel-Logic-Level-Translator-Converter-Bi-Directional-Module-p-1023173.html
I'll get some 3.3 and 5 V power supplies too.
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Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

Hello again list and Paul,

The USB and Mini-PCIe converters I ordered from Ebay China have not shown up
yet.
It appears PC Engines may take a while to release the custom BIOS that
exposes UART3 and 4 on the APU2  :/

In the interest of getting this working without waiting on a BIOS I will try
connecting it to COM1, which is wired to the DB9 connector.
https://pcengines.ch/pdf/apu2.pdf

Before I fry a 3.3V board with 5V signals, I hoped to ask here and confirm
my ideas.


Do I cross RX and TX lines from the GPS pins to the RX/TX on the DB9/COM1
connector?
And straight connect the PPS line from the GPS to the DCD pin on the
DB9/COM1 connector?

GPS:
http://pcengines.info/forums/?page=post=B4D54F22-8224-4A67-9F9E-85F988A1F
888



Thanks!
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Re: [time-nuts] Need 10 MHz for DSN space-probe hunting

[STR .]

>Briefly, Mike, there's an easy to use unit here, which takes a puck GPS 
>antenna and can run off USB +5V:
> http://www.leobodnar.com/shop/index.php?main_page=product_info_id=234
>
>Perhaps it might meet your needs?
>
>Cheers,
>David

Just wanted to add, their US distributor has one with a custom xtal that claims 
even lower phase noise and has provided a plot comparing the two:
http://www.force12inc.com/products/gps-locked-precision-frequency-reference-low-jitter-gps-clock-450-hz-to-800-mhz-output-custom-low-phase-noise-xtal-version.html

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Re: [time-nuts] What's the best Windows 10 ntp client?

[STR .]

https://www.meinbergglobal.com/english/sw/ntp.htm

It uses NTP and you can set the servers you like in its (typically) C:\Program 
Files (x86)\NTP\etc \ntp.conf


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of David J Taylor
Sent: Friday, September 2, 2016 1:18 PM
To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] What's the best Windows 10 ntp client?

At my amateur radio club we have Internet access via a WiFi dongle with a Pay 
As You Go card. A Windows 10 PC is only powered up while we are there, so on 
around 2-4 hours per week.

Does anyone have any thoughts on what might be the most suitable software to 
run on our Windows 10 PC to set the time correct?

Someone installed "Dimension 4"

http://www.thinkman.com/dimension4/

As far as I can see, this takes the time from one single NTP server, which I 
believe is not a good idea.  However,  given we only run the PC on 2-4 hours 
per week,  maybe no ntp client will work well,  but I would have thought using 
multiple servers being better than one.

I am wondering if anyone has any better suggestions for software. .

Dave.
___


Why not use the reference implementation - here for Windows:

  http://www.satsignal.eu/ntp/setup.html

Works with the NTP Pool selecting multiple servers.  For modes requiring better 
than 0.1 seconds accuracy consider adding a GPS/PPS to the PC. 
Performance available with NTP:

  http://www.satsignal.eu/mrtg/performance_ntp.php#windows-stratum-1

73,
David GM8ARV
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 

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Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

> [I'm responding to the list in case I need correcting]

>You started with NTP and my responses have all been in that context.  The 
>Soekris modification is an example of time-nut pursuit of a goal.  A side 
>effect was a very good NTP local clock.  If you goal is a very good local 
>clock then that's an approach.  If you goal is time transfer using NTP over 
>ethernet then it's >over-kill.  I'm not sure of your  goal.
>Modern replacements for the 4501 have been discussed previously.  E.g. the 
>BeagleBone Black can be clocked externally and has co-processors that can do 
>hi-res time stamps independent of the primary CPU.

Not at all Paul, my original question was about the APU2, I plan to use it as a 
router and I thought the GPS would be a fun addition.
The discussion sort of veered towards PTP and I apologize, I should've changed 
the subject to match.
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Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

> Most GBit NIC have hardware timestamping these days. Though I don't know if 
> whether the APU NICs do.

I found 6 Intel 1G NICs that list PTP (IEEE 1588) in their specs - Intel 82574, 
82576, 82580, I340, I350 and the I210 - 
https://communities.intel.com/community/wired/blog/2011/07/07/ieee-1588-update
Of those only 1 appears to do hardware timestamping for all Ethernet 
traffic(??) not just PTP - the Intel I340 - 
https://communities.intel.com/thread/87751

It appears the APU2 c4 model (which I have) has the Intel I210 NICs which do 
PTP, I'll check with Pascal/PC Engines if this is true.
As you and others have said the APU2+GPS via serial won't be a time-nuts 
standard time server, this isn't the time/clock source for adding a PTP switch 
to serve PTP NICs on the LAN. In time, perhaps :)

>From 
>http://www.intel.com/content/www/us/en/embedded/products/networking/i210-ethernet-controller-datasheet.html
Advanced Features:
—  Audio-video bridging
• IEEE 1588/802.1AS precision time synchronization

Time-nuts standards require implementations and physics/electronics knowhow 
that are way beyond me, I'm happy to lurk, learn and implement what little I 
can.
The lack of older, now inexpensive frequency standards hardware availability 
locally here is another barrier besides their shipping weight.
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Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

> Unless time-nuts levels of precision/accuracy are required, an APU is good 
> enough and an easy solution. If you go for time-nuts levels, then I would 
> question the use > of ethernet long before I question the hardware platform.

Not even ethernet with hardware PTP implementations, admittedly I haven't seen 
a NIC for sale with it?
I've always wondered if something like 
https://store.uputronics.com/index.php?route=product/product=60_70_id=92
 is worth the price over the likes of 
http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm 
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Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

> Finally, these boxes are intended to be routers (hence the three network
> interfaces) not time-servers and unless you're irrevocably wedded to the 
> miniPCIe in APU2 route there are probably better choices for time servers.

Paul,

John Ackermann's post on using the Soekris net4501 is what opened my eyes to 
GPSDO back then, sadly the TAPR Clock-Block clock synthesizer has not been 
available for sale since many years, although the FatPPS signal conditioner is.
Old net4501's are inexpensive, they do occasionally pop up on ebay for around 
$20-40 but as making the TAPR Clock-Block is not something I can do I never 
bought a 4501.

Is there an alternate replacement for the Clock-Block today? The soldering is 
out of my league but nothing the local TV/radio shop couldn't handle.
The net 4501 price today totally justifies another ntpd :)
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Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

Could another way be to cut out the mini-pci interface like 
http://galeria.tech-blog.pl/U-blox_PCI-5S_GPS/U-blox_PCI-5S_GPS_10.jpg.html 
though I'm not sure if he's driving it via serial?


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Scott Stobbe
Sent: Monday, August 22, 2016 10:46 PM
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Subject: Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC 
serial port for ntpd

The mini-PCI Express Card specification includes quite a bit more than just a 
single PCI-Express lane, there is also provisions for I2C (smbus), USB, LEDs, 
SIM, etc... While without looking a the physical card or specification I can't 
be certain, but I highly doubt it implements a PCI-Express interface. It is 
surely just using the USB interface over the express card slot. The GPS card 
should enumerate over the USB bus without any issues. In windows, ublox should 
provide you with USB drivers for their modules.

You will have to experiment to see if the RX/TX lines of the GPS module are 
active after a POR, or if it defaults to USB, as that is how it was intended to 
be used. But the PPS line definitely needs to be connected to one of modem 
control lines of a UART.

On Sun, Aug 21, 2016 at 11:30 AM, STR . <stry...@hotmail.com> wrote:

> Thank you!
> Your post has made my choices clear, UART-c might be it!
> A previous poster said there'd be no difference in jitter using any of 
> the
> 4 COM ports and this was reassuring.
> I will start studying the pinouts to confirm the pin numbers while I 
> wait for the null-modem cable to arrive.
>
> Another question, would connecting PPS, Tx/Rx to the GPIO pins on 
> UART-c make U-blox's Windows u-Center software see this as attached to 
> a physical serial port?
> If not, how would I present the GPS to Windows via serial?
> I'd like to test updating the firmware and it appears to not work via 
> a mini-pci to WWAN 3G USB adapter.
>
> Others have reported:
> "After Emeryth published the pinout, I also started to experiment with 
> this board. I found out that you can update the firmware using the 
> LEA-5 firmware version 6.02 from the u-blox web site. The module also 
> works very well with the patched firmware version EXT_G50_602_LEA-5H.
> bdbfccefb9dbd8395dec7adece53c1f9.bin. This version enables the output 
> of raw data for use with rtklib for real-time kinematic and precision 
> positioning.
>
> You can then use the standard drivers from the u-blox web site for 
> Windows. They provide a virtual COM port. Please note that updating 
> the firmware just worked using the physical serial port of the 
> Mini-PCIe card, it did not work using the USB adapter."
>
>
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Paul
> Sent: Tuesday, August 16, 2016 2:27 AM
> To: Discussion of precise time and frequency measurement < 
> time-nuts@febo.com>
> Subject: Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to 
> APU2 SoC serial port for ntpd
>
> On Mon, Aug 15, 2016 at 5:35 AM, STR . <stry...@hotmail.com> wrote:
>
> > Pardon my ignorance, I'm not sure what COM port the PPS is tied to 
> > or what you mean.
>
>
> I think there's some confusion.
>
> Normally the PPS input to Linux (I'm not sure about FreeBSD) is tied 
> to the DCD pin in a serial port.  The PPS code is connected to the 
> interrupt from the DCD.  It can be tied to another pin (DSR or CTS I 
> forget), a parallel port or a GPIO pin (a la RaspberryPi or 
> BeagleBone).  Anything other than DCD normally requires a specific 
> kernel build.  The APU2c has an I/O part connected via an LPC bus.  
> It's essentially 4 UARTS.  UART-a is connected to a DE-9 connector via 
> a level shifter.  All signals are present.  UART-b is brought to J3 
> unshifted.  Even though J3 has five pins only transmit, receive and 
> ground are connected.  UARTs "c" and "d" are brought to J17 either as 
> 18 GPIO signals or 2x8 RS-232 signals (the latter requires 
> non-standard bios code to set up the chip).  So if we imagine that you 
> want to use the DCD pin on UART-c you'd configure the GPIO pins as 
> serial and connect to pin 9 on J17.  Be advised that the specifics in the 
> previous may be wrong so check the schematic.
>
> Now if you want to read the correct time as a sentence from the GPS 
> you'd connect the Tx/Rx pins on your module to the corresponding pins 
> on a 3V3 serial port.  Continuing to use UART-c that would be pins 7 and 8 on 
> J17.
>
> Now regarding jitter.  Pascal suggests that the jitter involved in 
> using his take on the LPC connected super i/o part might be too high.  
> As note

Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

I bought 2 of these just in case I trash one while updating the firmware.
If it doesn't work in the APU, I could order a mini-PCI to PCI converter 
adapter and see if I can get the other one going in a desktop.


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Scott Stobbe
Sent: Monday, August 22, 2016 10:46 PM
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Subject: Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC 
serial port for ntpd

The mini-PCI Express Card specification includes quite a bit more than just a 
single PCI-Express lane, there is also provisions for I2C (smbus), USB, LEDs, 
SIM, etc... While without looking a the physical card or specification I can't 
be certain, but I highly doubt it implements a PCI-Express interface. It is 
surely just using the USB interface over the express card slot. The GPS card 
should enumerate over the USB bus without any issues. In windows, ublox should 
provide you with USB drivers for their modules.

You will have to experiment to see if the RX/TX lines of the GPS module are 
active after a POR, or if it defaults to USB, as that is how it was intended to 
be used. But the PPS line definitely needs to be connected to one of modem 
control lines of a UART.

On Sun, Aug 21, 2016 at 11:30 AM, STR . <stry...@hotmail.com> wrote:

> Thank you!
> Your post has made my choices clear, UART-c might be it!
> A previous poster said there'd be no difference in jitter using any of 
> the
> 4 COM ports and this was reassuring.
> I will start studying the pinouts to confirm the pin numbers while I 
> wait for the null-modem cable to arrive.
>
> Another question, would connecting PPS, Tx/Rx to the GPIO pins on 
> UART-c make U-blox's Windows u-Center software see this as attached to 
> a physical serial port?
> If not, how would I present the GPS to Windows via serial?
> I'd like to test updating the firmware and it appears to not work via 
> a mini-pci to WWAN 3G USB adapter.
>
> Others have reported:
> "After Emeryth published the pinout, I also started to experiment with 
> this board. I found out that you can update the firmware using the 
> LEA-5 firmware version 6.02 from the u-blox web site. The module also 
> works very well with the patched firmware version EXT_G50_602_LEA-5H.
> bdbfccefb9dbd8395dec7adece53c1f9.bin. This version enables the output 
> of raw data for use with rtklib for real-time kinematic and precision 
> positioning.
>
> You can then use the standard drivers from the u-blox web site for 
> Windows. They provide a virtual COM port. Please note that updating 
> the firmware just worked using the physical serial port of the 
> Mini-PCIe card, it did not work using the USB adapter."
>
>
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Paul
> Sent: Tuesday, August 16, 2016 2:27 AM
> To: Discussion of precise time and frequency measurement < 
> time-nuts@febo.com>
> Subject: Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to 
> APU2 SoC serial port for ntpd
>
> On Mon, Aug 15, 2016 at 5:35 AM, STR . <stry...@hotmail.com> wrote:
>
> > Pardon my ignorance, I'm not sure what COM port the PPS is tied to 
> > or what you mean.
>
>
> I think there's some confusion.
>
> Normally the PPS input to Linux (I'm not sure about FreeBSD) is tied 
> to the DCD pin in a serial port.  The PPS code is connected to the 
> interrupt from the DCD.  It can be tied to another pin (DSR or CTS I 
> forget), a parallel port or a GPIO pin (a la RaspberryPi or 
> BeagleBone).  Anything other than DCD normally requires a specific 
> kernel build.  The APU2c has an I/O part connected via an LPC bus.  
> It's essentially 4 UARTS.  UART-a is connected to a DE-9 connector via 
> a level shifter.  All signals are present.  UART-b is brought to J3 
> unshifted.  Even though J3 has five pins only transmit, receive and 
> ground are connected.  UARTs "c" and "d" are brought to J17 either as 
> 18 GPIO signals or 2x8 RS-232 signals (the latter requires 
> non-standard bios code to set up the chip).  So if we imagine that you 
> want to use the DCD pin on UART-c you'd configure the GPIO pins as 
> serial and connect to pin 9 on J17.  Be advised that the specifics in the 
> previous may be wrong so check the schematic.
>
> Now if you want to read the correct time as a sentence from the GPS 
> you'd connect the Tx/Rx pins on your module to the corresponding pins 
> on a 3V3 serial port.  Continuing to use UART-c that would be pins 7 and 8 on 
> J17.
>
> Now regarding jitter.  Pascal suggests that the jitter involved in 
> using his take on the LPC connected super i/o part might be 

Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

Thank you!
Your post has made my choices clear, UART-c might be it!
A previous poster said there'd be no difference in jitter using any of the 4 
COM ports and this was reassuring.
I will start studying the pinouts to confirm the pin numbers while I wait for 
the null-modem cable to arrive.

Another question, would connecting PPS, Tx/Rx to the GPIO pins on UART-c  make 
U-blox's Windows u-Center software see this as attached to a physical serial 
port?
If not, how would I present the GPS to Windows via serial?
I'd like to test updating the firmware and it appears to not work via a 
mini-pci to WWAN 3G USB adapter.

Others have reported:
"After Emeryth published the pinout, I also started to experiment with this 
board. I found out that you can update the firmware using the LEA-5 firmware 
version 6.02 from the u-blox web site. The module also works very well with the 
patched firmware version 
EXT_G50_602_LEA-5H.bdbfccefb9dbd8395dec7adece53c1f9.bin. This version enables 
the output of raw data for use with rtklib for real-time kinematic and 
precision positioning.

You can then use the standard drivers from the u-blox web site for Windows. 
They provide a virtual COM port. Please note that updating the firmware just 
worked using the physical serial port of the Mini-PCIe card, it did not work 
using the USB adapter."



-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Paul
Sent: Tuesday, August 16, 2016 2:27 AM
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Subject: Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC 
serial port for ntpd

On Mon, Aug 15, 2016 at 5:35 AM, STR . <stry...@hotmail.com> wrote:

> Pardon my ignorance, I'm not sure what COM port the PPS is tied to or 
> what you mean.


I think there's some confusion.

Normally the PPS input to Linux (I'm not sure about FreeBSD) is tied to the DCD 
pin in a serial port.  The PPS code is connected to the interrupt from the DCD. 
 It can be tied to another pin (DSR or CTS I forget), a parallel port or a GPIO 
pin (a la RaspberryPi or BeagleBone).  Anything other than DCD normally 
requires a specific kernel build.  The APU2c has an I/O part connected via an 
LPC bus.  It's essentially 4 UARTS.  UART-a is connected to a DE-9 connector 
via a level shifter.  All signals are present.  UART-b is brought to J3 
unshifted.  Even though J3 has five pins only transmit, receive and ground are 
connected.  UARTs "c" and "d" are brought to J17 either as 18 GPIO signals or 
2x8 RS-232 signals (the latter requires non-standard bios code to set up the 
chip).  So if we imagine that you want to use the DCD pin on UART-c you'd 
configure the GPIO pins as serial and connect to pin 9 on J17.  Be advised that 
the specifics in the previous may be wrong so check the schematic.

Now if you want to read the correct time as a sentence from the GPS you'd 
connect the Tx/Rx pins on your module to the corresponding pins on a 3V3 serial 
port.  Continuing to use UART-c that would be pins 7 and 8 on J17.

Now regarding jitter.  Pascal suggests that the jitter involved in using his 
take on the LPC connected super i/o part might be too high.  As noted someone 
said that was the case with the APU1.  While I wouldn't be surprised if that 
were still true with the APU2 you might find the time "good enough".  Trust but 
verify.

Finally, these boxes are intended to be routers (hence the three network
interfaces) not time-servers and unless you're irrevocably wedded to the 
miniPCIe in APU2 route there are probably better choices for time servers.
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Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

Pardon my ignorance, I'm not sure what COM port the PPS is tied to or what you 
mean.

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Albertson
Sent: Monday, August 15, 2016 2:30 AM
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Subject: Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC 
serial port for ntpd

Why not use the same COM port the PPS is tied to.  Apparently in can accept the 
3 volt serial signal.  The PPS goes to one of the control lines to create an 
interrupt and the data goes to Rx and Tx.

On Sun, Aug 14, 2016 at 9:37 AM, STR . <stry...@hotmail.com> wrote:

> Thanks for your previous email, it shed light on the situation of 
> choosing COM ports.
>
> COM1 is required for console access so that's out.
> COM2 has headers and seemed like an obvious choice as I have no real 
> need for a 2nd serial port.
>
> I wish to power the GPS via the mini-PCI slot to avoid soldering power 
> cables along with a PPS line.
> Will there be any difference in jitter between using the COM2 header 
> or
> COM3 provided by the NCT5104D GPIO pins?
> Or will they both be identical in performance?
>
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of 
> Attila Kinali
> Sent: Sunday, August 14, 2016 5:30 PM
> To: Discussion of precise time and frequency measurement < 
> time-nuts@febo.com>
> Subject: Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to 
> APU2 SoC serial port for ntpd
>
> On Sun, 14 Aug 2016 08:29:48 +
> "STR ." <stry...@hotmail.com> wrote:
>
> > Serial port 3 and 4 are provided via the GPIO pins connected to an
> NCT5104D I/O controller which is 5V tolerant.
> > http://datasheet.octopart.com/NCT5104D-Nuvoton-datasheet-38893851.pd
> > f I believe that's why it was suggested to avoid the 3V-5V 
> > conversion.
>
> Oops.. I missed that the other UARTs were connected to the GPIO header.
>
> If you use those, you can directly connect the LEA outputs, as the LEA 
> does use 3.3V CMOS for I/O.
>
> Attila Kinali
> --
> Malek's Law:
> Any simple idea will be worded in the most complicated way.
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Chris Albertson
Redondo Beach, California
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Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

Thanks for your previous email, it shed light on the situation of choosing COM 
ports.

COM1 is required for console access so that's out.
COM2 has headers and seemed like an obvious choice as I have no real need for a 
2nd serial port.

I wish to power the GPS via the mini-PCI slot to avoid soldering power cables 
along with a PPS line.
Will there be any difference in jitter between using the COM2 header or COM3 
provided by the NCT5104D GPIO pins?
Or will they both be identical in performance?


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila Kinali
Sent: Sunday, August 14, 2016 5:30 PM
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Subject: Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC 
serial port for ntpd

On Sun, 14 Aug 2016 08:29:48 +0000
"STR ." <stry...@hotmail.com> wrote:

> Serial port 3 and 4 are provided via the GPIO pins connected to an NCT5104D 
> I/O controller which is 5V tolerant.
> http://datasheet.octopart.com/NCT5104D-Nuvoton-datasheet-38893851.pdf
> I believe that's why it was suggested to avoid the 3V-5V conversion.

Oops.. I missed that the other UARTs were connected to the GPIO header.

If you use those, you can directly connect the LEA outputs, as the LEA does use 
3.3V CMOS for I/O.

Attila Kinali
--
Malek's Law:
Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

What details would you like to know?

Serial port 3 and 4 are provided via the GPIO pins connected to an NCT5104D I/O 
controller which is 5V tolerant.
http://datasheet.octopart.com/NCT5104D-Nuvoton-datasheet-38893851.pdf
I believe that's why it was suggested to avoid the 3V-5V conversion.


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Albertson
Sent: Sunday, August 14, 2016 12:01 PM
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Subject: Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC 
serial port for ntpd

It looks like you would have to level-convert the 3 volt PPS to connect to
one of the GPIO pins.   It is easy to make a level converter with a FET or
you can buy one for $3 from Adafruit or spark fun.As for the serial
data, that will be easy as there seems to be a 3 volt serial port.

The direct connection that was suggested might work or might not it depends on 
some details we don't know.

Seems like a good low power embedded PC.   Very much over kill for just
running NTP but I assume this will do other things too.

On Sat, Aug 13, 2016 at 7:32 PM, STR . <stry...@hotmail.com> wrote:

> Hi,
>
>
>
> I recently bought 2 ublox PCI-5S mini-PCI GPS modules and have ordered 
> a PCengines APU2C4 board I hope to install it in.
>
> Others have found it can provide PPS output http://emerythacks.blogspot.
> in/2013/01/u-blox-pci-5s-cheap-gps-module-for-your.html
>
>
>
> This is the x-64 AMD SoC by PCengines - 
> http://www.pcengines.ch/apu2c4.htm
>
> Schematics - http://www.pcengines.ch/schema/apu2c.pdf
>
> User manual (Page 8 has a nice overview of the board) - 
> http://www.pcengines.ch/pdf/apu2.pdf
>
>
>
> I would like to install and power the GPS from the mini-PCI slot and 
> output PPS directly on to one of the serial ports on the SoC board for ntpd.
>
> Since mini-PCI uses  3.3V and serial uses 5V I guess, I'm not sure how 
> to achieve this and am concerned I might fry the board.
>
>
>
> Do I need a MAX 232 voltage converter?
>
> Can this be done using the mini-PCI slot for power?
>
>
>
> I have posted my issue on the PCengines forum and got 1 response so 
> far that suggested I connect to COM3 on the GPIO header  -
>
> http://www.pcengines.info/forums/?page=post=B4D54F22-
> 8224-4A67-9F9E-85F988A1F888=DF5ACB70-99C4-4C61-AFA6-4C0E0DB05B2A
>
> I'm not sure where exactly, these are the GPIO pins on the board 
> http://imgur.com/a/bAZLb
>
>
>
> When someone says "LPC serial IRQ and system interrupt latency will 
> add up to noticeable jitter" does that mean the jitter would be 
> equally bad from any serial port on the board or just from the 3rd serial off 
> the GPIO pins?
>
> Here, someone else claims the PPS should have less jitter in a similar 
> setup - http://pcengines.info/forums/?page=post=CD275C4D-8050-
> 408A-BD16-6F50468C74C2
>
>
>
> I'm hoping someone here could help me out with this as I'm well in 
> over my head by now.
>
>
>
>
>
>
>
> Cheers,
>
> S
>
> ___
> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
> https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow 
> the instructions there.
>



-- 

Chris Albertson
Redondo Beach, California
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[time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

[STR .]

Hi,



I recently bought 2 ublox PCI-5S mini-PCI GPS modules and have ordered a 
PCengines APU2C4 board I hope to install it in.

Others have found it can provide PPS output 
http://emerythacks.blogspot.in/2013/01/u-blox-pci-5s-cheap-gps-module-for-your.html



This is the x-64 AMD SoC by PCengines - http://www.pcengines.ch/apu2c4.htm

Schematics - http://www.pcengines.ch/schema/apu2c.pdf

User manual (Page 8 has a nice overview of the board) - 
http://www.pcengines.ch/pdf/apu2.pdf



I would like to install and power the GPS from the mini-PCI slot and output PPS 
directly on to one of the serial ports on the SoC board for ntpd.

Since mini-PCI uses  3.3V and serial uses 5V I guess, I'm not sure how to 
achieve this and am concerned I might fry the board.



Do I need a MAX 232 voltage converter?

Can this be done using the mini-PCI slot for power?



I have posted my issue on the PCengines forum and got 1 response so far that 
suggested I connect to COM3 on the GPIO header  -

http://www.pcengines.info/forums/?page=post=B4D54F22-8224-4A67-9F9E-85F988A1F888=DF5ACB70-99C4-4C61-AFA6-4C0E0DB05B2A

I'm not sure where exactly, these are the GPIO pins on the board 
http://imgur.com/a/bAZLb



When someone says "LPC serial IRQ and system interrupt latency will add up to 
noticeable jitter" does that mean the jitter would be equally bad from any 
serial port on the board or just from the 3rd serial off the GPIO pins?

Here, someone else claims the PPS should have less jitter in a similar setup - 
http://pcengines.info/forums/?page=post=CD275C4D-8050-408A-BD16-6F50468C74C2



I'm hoping someone here could help me out with this as I'm well in over my head 
by now.







Cheers,

S

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