How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd
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 -
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&id=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
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 . strykar@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&id=B4D54F22-
8224-4A67-9F9E-85F988A1F888&fid=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&id=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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To unsubscribe, go to https://www.febo.com/cgi-bin/
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--
Chris Albertson
Redondo Beach, California
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-bounces@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 . strykar@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&id=B4D54F22-
8224-4A67-9F9E-85F988A1F888&fid=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&id=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
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.
On Sun, 14 Aug 2016 02:32:13 +0000
"STR ." strykar@hotmail.com wrote:
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.
It depends on where you want to connect it to. You have 3 choices:
- COM1 after the level converter
- COM1 before the level converter
- COM2
Option 1) needs +/-5V, options 2) and 3) work with 3.3V.
But: both options 2) and 3) require you soldering directly
onto the APU board: for 2) you need to unsolder U37 and you will
lose your console serial port. For 3) you need to solder wires
directly onto the pins of U9 as the signals have not been broken
out onto testpoints.
For more information, see the APU schematics and the NCT5104D datasheet.
Attila Kinali
--
Malek's Law:
Any simple idea will be worded in the most complicated way.
On Sun, 14 Aug 2016 08:29:48 +0000
"STR ." strykar@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.
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-bounces@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 ." strykar@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.
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.
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 . strykar@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-bounces@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 ." strykar@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.
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.
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
On Sun, Aug 14, 2016 at 12:37 PM, STR . strykar@hotmail.com wrote:
COM2 has headers and seemed like an obvious choice as I have no real need
for a 2nd serial port.
COM2 does not have control lines. Unless you're going to rewrite the PPS
kernel module you have to use COM1 or GPIO. Sadly GPIO is not plug and
play. However it's not impossible. Someone on the PCEngines forum may have
done it already.
From the doc pages 8/9.
J3 COM2 3.3V serial port (RXD / TXD only).
...
J22 COM1 Serial port. Full handshake signals this time...
P.S.
Pascal's comment about jitter is not relevant to normal NTP.
--
Paul
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-bounces@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 . strykar@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-bounces@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 ." strykar@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.
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.
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
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.
There should be no difference between COM2 or COM3/4, all four UARTs are
likely hard logic. GPIO is just an alternate function for the COM3/4 pins.
It will come down to what your are more comfortable with code or soldering.
The NCT5104D is a QFP and its pins are reasonably accessible using 30 AWG
or finer gauge wire.
On Sun, Aug 14, 2016 at 12:37 PM, STR . strykar@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-bounces@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 ." strykar@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.
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.
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.