Dear Radek, dear all,

to reducing wiring, I soldered the A4988 on a diy proto HAT, i.e.to plug the board on top of the RPi. To accomodate the sequence of the A4988 pins, I changed the GPIO assignment in the rpi_focus.cpp file. All fine, but I cannot change the resolution as desired (set speed to case 5) - I am targetting 1/8, i.e. M0 = High and M1 = High for the A4988. However, both seem to remain "low" (full step). M0 is assigned to GPIO9 (physical pin 21, MISO) and M1 to GPIO10 (physical pin 19, MOSI).

Could it be that using the MISO / MOSI as output pins is not advisable?

Best wishes for 2018!

Helge

I believe you can change the GPIO assignment as much as you wish. However if you use pins which are used for other purposes (in your case you're using SPI pins) you need to make sure there's no conflict. In your configuration you need to disable SPI in your /boot/config.txt (dtparam=spi=off) and everything should work just fine. As for now you probably have SPI enabled so using this pins as regular GPIO is just not possible.

All the best in 2018!

Eventually ‘mission accomplished’. Interesting to note: despite disabling spi, the gpio’s 9 and 10 did not show any signal, also checked with the voltmeter. So I moved the a4988 a bit to the left to use other GPIOs and now I am able to change the resolution to 1/8 (via M0 and M1) which is more smooth than the full step and by far less noisy.

Now the board looks very messy, after resoldering. Once I have a nicer version (assembled on the diy prototype HAT), I will post a picture.

In any case, I really like the astroberry focuser, and it should become part of the standard drivers available when doing the general installation of indi-drivers (indi-full). Is there a reason why it is not?

I'm glad it works for you!
As the matter of fact the driver depends on a few low level libraries, which are not normally distributed with popular systems. To overcome this, the driver compiles them in statically so the source code uses submodules. Submodules are not supported by launchpad and this is the show stopper because launchpad is used to autobuild all INDI packages. As the result we cannot include the driver in the main distribution. Maybe in the future, but this will need some major reengineering of the drivers.