[time-nuts] DeLorme Tripmate GPS receiver
michael.cook at sfr.fr
Tue Dec 23 01:45:52 EST 2014
> Le 23 déc. 2014 à 01:41, Ryan Stasel <rstasel at uoregon.edu> a écrit :
> Not 100% sure this is the same model, but it would seem to indicate there's a PPS signal on the DCD pin (from the gpsd-users list circa 2007): http://marc.info/?l=gpsd-users&m=118340900010559&w=2
> Have a 'scope to check what that pin looks like?
Unfortunately, according to <http://n3ujj.com/TripMate_Self_Start_Modification.html> , this signal is not available on the DB9 output.
I have a working Jupiter TU60-D120 timing receiver which appears to use this chip (sourced from Sirf) which has a 1PPS on the headers pin6. I spent some time yesterday trying to trace back that pin to the 11577-11, but failed. I think I would need to probe it under power to go further but am hitting a couple of issues that are holding me up.
The first is plain logistics. I have no free 12V power for the mother board (supplies buffered 10KHz and 1PPS on SMA plus a DB9 out) and the second more important is that I don’t know how to be sure of not shorting the 11577-11 pins when probing if it is power up. It’s a .5mm pitch chip and my probe which is pointed has the habit of slipping off the pins. There must be special tips to prevent that but I don’t have one. Any tips (as in help) appreciated. Another difficulty is keeping an eye on the scope while at the same time probing. This is a recurring problem that I don’t know how to fix. I expect that there are logic probes made for SMDs but I have none of those either.
I will get a new 12V source after Xmas and have a careful poke. If anyone knows of a source of cheap(ish) isolated probes (or removable tips) or a convenient work around, I would appreciate the help.
Happy holidays to all,
> -Ryan Stasel
>> On Dec 21, 2014, at 23:07 , ed breya <eb at telight.com> wrote:
>> One thing I want to clarify - it is not a Jupiter GPS module - it just uses the chipset, presumably hooked up as in the application info. The board is proprietary, and there seems to be no standard electrical or operational interface as would be expected in an OEM GPS module. So, the only way to figure it out is to go by the chip details to see how it's supposed to work.
>> previous message:
>> I peeled open the shield can without too much deformation, so it can be restored. I found that it's a single board, with the DSP on one side, and the RF section on the other. It is a Rockwell chipset, with 11577-11 DSP, and 6732-13 RF. On searching I found that this seems to be called their Jupiter GPS from circa late 1990s - I found quite a lot of info at the module level, but not for the actual ICs, like pinout data. The set includes all the usual GPS stuff including 1 PPS, and is capable of several levels of on-ness. So, if the uP that makes it a DeLorme merely sets some control lines to activate it, then I should be able to override them to force it always on - if I can figure them out. If instead the uP programs something internal to the DSP to control power states, then fuggetabout it - it will be junk.
>> So, does anyone know of the Jupiter chipset, and where to find chip-level info for these parts?
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