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[mramirez]

Hi Tom
I have some questions about ST4
1-   In order to use ST4 connector, if I am right, you need to connect JP1 and JP2. What is the purpose of these JPs? Why didn’t you make the footprint of these four connections by default?
2-   On ST4 (1), what is the (IO0) for?
3-   Let say telescope is tracking at sidereal speed. If I connect JP1 (RA+) directly to GND, the telescope would go faster to west? Or do I need any other connection and/or action?
Thanks for your help and your patient.
Mateo

[TCWORLD]

Hi Mateo,

1. You don't need to connect JP1 and JP2. These are already connected on the top layer of the PCB. In fact none of the small headers on the board need connecting for the purchased PCBs.
The connector footprints are only there to allow people to home etch a single-sided version of the design.

2. For a standard ST-4 guider, pin 1 (IO0) is unused. This pin has a custom use on the AstroEQ to enable a push-button controlled mode to allow use of the AstroEQ without a PC for basic tracking an manual slews (see here for details).

3. Correct, simply connecting the four ST-4 pins (RA+/- and DEC+/-) to ground will cause the telescope to change the tracking speed relative to the sidereal rate. The change is selected via the configuration utility. For example if you selected 0.25x in the config utility, then RA+ would track at 1.25x sidereal, RA- would track at 0.75x sidereal, neither would track at 1x. Pressing DEC+/- would cause the DEC axis to additionally slew at 0.25x sidereal while pressed.

[mramirez]

Hi Tom

1-   Sorry Tom, I was not aware of these connections.
2-   Understood. Taking a look at the link about the fob, is there any chance to know the connections inside the fob with the (ATTiny10) microcontroller?
3-   Ok Tom, I have test what you said and, of course, it works.

Thanks again.

Mateo