Re: SHC Connection to OnSTEP STM32

Dave Schwartz

If you are getting the 'connection failed' message on the display then the pins are wired correctly.

Be sure that the cable you are using for an ST4 cable is correct. A real ST4 cable is wired straight-through... many that are for telephone use have some crossover wiring. An ST4 cable looks like this image - note that the wire colors are in the same order left-to-right.

On 2020-01-12 12:17 p.m., wrote:
Hello erveryone,

I am looking for my problem with the connection SHC to OnStep STM32 Blue Pill.

The Status is:
OnStep works fine with the App and Sky Planetarium.
In config.STM32.h the SHC are following defined: #define ST4_PULLUP and #define ST4_HAND_CONTROL_ON.
The pullup resistor on Onstep and on SHC are mounted.

If the ST4 cabel is connected the SHC display shows after a few seconds: "connection failed"
Also when only the USB cabel is connected on the teensy 3.2.
I also tried two different ST4 cabel. But without success.

Maybe the problem is the display? The pins are VDD, GND, SCK, SDA. The order of pin (GND,VCC) are differnt between the SHC PCB and the display.
So I did make sure that GND and VCC are right connected with SHC PCB and the display.
But maybe the problem is the pin *SCK*? On the PCB this pin namend SCL.

Thanks for your support!

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