Cheap Chinese TB6600 with RAMPS (no replies)

Hey all,

so I've bought 4 cheap Chinese TB6600 stepper drivers.
[www.ebay.com]

I have included 2 pictures. will add 1 picture more, from the chip on the downside of the PCB, soon.

I thought they would be useful for the two ACME threaded stepper motors used on the Z-axis.
However, they appeared quite a challenge.
No datasheet to be found on this type.
However, the online floating datasheet of the TB6600 did give me some ideas.

While ENA- and PUL- are grounded. the Dir - and Dir+ (+5v) needs to be controlled.
When using the standard configuration; Dir- to ground and Dir+ to signal, it turn clockwise. (Signal being LOW)
But to turn counterclockwise, the configuration needs to be; Dir- to signal and Dir+ to ground.

The operating frequency is 20Khz, so per pulse it needs to be 50 microseconds.

I have some issues with Marlin, to add this to the firmware.
So, please help me with this.
I was thinking on either using the sleep or reset connection of the stepper driver connections for either Dir- or Dir+

kind regards,
Lorcan