Movement in one direction only!

[ricardocjcosta]

Hello!
First of all I want to thank you for sharing the firmware you developed.
I'm building a robot scara for a learning project. The mechanical part is not yet completed. However, I have done some testing using 2 engines, in order to test the communications between hardware.
Among others, I also used the firmware that you developed and there is something that intrigues me.
When simulating a configuration for single scara, for ramps 1.4 etc ... I try to manually control the motors, in this case X and Y, I only have movement of the two motors in one direction and only when I select the motor Y. I only get movement in one direction. When I select the X engine, it never react. Neither one nor the other.
Is there any poorly configured configuration that can cause this?
I made simulations using the Repetier host, Pronterface and even RepRap Discount Full Graphic Smart Controller. I get the same result at all. The motors move only in one direction and only by selecting Y.
I send here a link of a video where you can observe a test with pronterface and RepRap Discount Full Graphic Smart Controller.
With the repeat host I get the same result.

https://www.youtube.com/watch?v=bjJlYlG050Y&feature=youtu.be

Thank you for your attention.