On 19/06/2022 16:17, Jim Pennino wrote:
which is why I would question your "which should be a DB-25".
It's RS232's should be. Actually, Wikipedia seems to say that the D
version says must be. A lot of this thread is about RS232 compliance,
and part of that compliance is using the correct co
I use the Raspberry pi with GPS hat and it works great. 100 dollars and
you have a great NTP server
Chip
On Sun, Jun 19, 2022 at 8:33 AM David Woolley
wrote:
> On 19/06/2022 13:46, Jim Pennino wrote:
> > CTS/RTS is pin 8 on a RS-232 connector, so how is that "PPS over USB"?
>
> CTS is on pin 5
On 19/06/2022 13:46, Jim Pennino wrote:
CTS/RTS is pin 8 on a RS-232 connector, so how is that "PPS over USB"?
CTS is on pin 5, and RTS on pin 4, on an RS232 connector, which should
be a DB-25 one.
The DE-9 connector, used on PCs, is a TIA-574 connector, not an RS232
one, and RTS is on pin
On 19/06/2022 07:38, Daniel O'Connor wrote:
OK, then to which of the USB connector pins do you connect the PPS
signal to get "PPS over USB"?
You can connect them to CTS or RTS, on FreeBSD these can then hook into the
kernel PPS API.
It works very well in practise, especially for the cost & e
On 17/06/2022 20:45, Jim Pennino wrote:
Have fun writting the necessary device driver...
You can buy chips preloaded with the relevant code for the encode side,
for single figure sums and most OSes already include the decode side code.
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On 17/06/2022 20:16, Terje Mathisen wrote:
The key idea is of course that in order to know where a GPS is located
with better than 3 m precision, the unit by implication also knows what
time it is, to within 10 ns of UTC(USNO). The only problem is to be able
to convey that info to a connected N
I like the adafruit gps hat
Chip Blach
On Fri, Jun 17, 2022, 1:16 PM Terje Mathisen wrote:
> David Woolley wrote:
> > On 17/06/2022 16:34, chris wrote:
> >> As for compatibility, while a mismatched connection may work, it's bad
> >> practice to do that, where you are dealing with microsecond ti
David Woolley wrote:
On 17/06/2022 16:34, chris wrote:
As for compatibility, while a mismatched connection may work, it's bad
practice to do that, where you are dealing with microsecond timing
and want to avoid jitter. Use the correct interfaces and do the job
right, then you can fit and forget:
On 17/06/2022 15:01, Jim Pennino wrote:
OK, then to which of the USB connector pins do you connect the PPS
signal to get "PPS over USB"?
D+ and D-, using for example a Communications Device Class module to
encode it for transmission. I guess HID would be more appropriate, for
an isolated dig
On 17/06/2022 16:34, chris wrote:
As for compatibility, while a mismatched connection may work, it's bad
practice to do that, where you are dealing with microsecond timing
and want to avoid jitter. Use the correct interfaces and do the job
right, then you can fit and forget:-)...
RS232 isn't op
Daniel O'Connor wrote:
>
>
>> On 17 Jun 2022, at 12:52, Jim Pennino wrote:
>> Daniel O'Connor wrote:
>>>
>>>
On 17 Jun 2022, at 00:07, David Taylor
wrote:
On 16/06/2022 10:00, Thiebaud HUMBERT wrote:
> To do the inversion, I just changed the "Pulse Mode" parameter
I have complete instructions on how to use a raspberry pi as an NTP server.
Ping me if you want them
Chip Blach
On Fri, Jun 17, 2022, 8:08 AM David Taylor
wrote:
> On 17/06/2022 03:03, Daniel O'Connor wrote:
> >> Yes, Thiebaud, USB is not good enough for PPS signals!
> > This is absolutely fal
On 17/06/2022 03:03, Daniel O'Connor wrote:
Yes, Thiebaud, USB is not good enough for PPS signals!
This is absolutely false.
If you are using it for NTP then GPS+PPS over USB is quite adequate (from
personal experience).
Ian Lepore (RIP) who worked for Micro Semi and worked on FreeBSD did a b
On 17/06/2022 00:55, chris wrote:
No argument with that, but some have tried to bypass a converter,
feeding the ttl pps into the rs232 port, which may work in some
cases. TLL pps low level, in particular, won't guarantee the rs232
input line to switch, whereas, of course, the ttl high will switch
Daniel O'Connor wrote:
>
>
>> On 17 Jun 2022, at 00:07, David Taylor
>> wrote:
>>
>> On 16/06/2022 10:00, Thiebaud HUMBERT wrote:
>>> To do the inversion, I just changed the "Pulse Mode" parameter to "Falling
>>> edge" from "Rising edge".
>>> The offset induced by the "pulse length" has disa
Quoting Daniel O'Connor :
If you are using it for NTP then GPS+PPS over USB is quite adequate
(from personal experience).
Ian Lepore (RIP) who worked for Micro Semi and worked on FreeBSD did
a bunch of tests on a PPS over USB setup and found it more than
acceptable for keeping a PC in (good)
chris wrote:
> On 06/16/22 16:20, Jim Pennino wrote:
>> Thibaut HUMBERT wrote:
>>> Le jeudi 16 juin 2022 à 16:37:33 UTC+2, David Taylor a écrit :
On 16/06/2022 10:00, Thiebaud HUMBERT wrote:
> To do the inversion, I just changed the "Pulse Mode" parameter to
> "Falling edge" from "R
On 16/06/2022 15:54, Thibaut HUMBERT wrote:
I have a serial port, but I don't know how to convert the PPS output (0 / 3.3V)
to RS232 (-5V / +5V).
RS232 is +/-12V, although, input values of +/-3V are unequivocal. In
practice line receivers have both positive and negative going thresholds
> 0
Thibaut HUMBERT wrote:
> Le jeudi 16 juin 2022 à 16:37:33 UTC+2, David Taylor a écrit :
>> On 16/06/2022 10:00, Thiebaud HUMBERT wrote:
>> > To do the inversion, I just changed the "Pulse Mode" parameter to "Falling
>> > edge" from "Rising edge".
>> > The offset induced by the "pulse length" ha
On 16/06/2022 10:00, Thiebaud HUMBERT wrote:
To do the inversion, I just changed the "Pulse Mode" parameter to "Falling edge" from
"Rising edge".
The offset induced by the "pulse length" has disappeared.
But there is still an offset of around 10.3ms, which I think is induced by USB
as explained
On 16/06/2022 09:01, Thibaut HUMBERT wrote:
When I modify the PPS pulse length in u-center, the offset varies:
I would suggest you are detecting the wrong edge of the pulse. You may
need to add an inverter.
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