New component for keyboards and panels.

It is probably possible to do it with two sendkeys components, wiring the pins to both and enabling one or the other.

I think that a better way would be to add a new code to the config string, (maybe a for alternate) "a2" would create two "shift bits" as pins, and then the scancode params would be:
setp sendkeys.0.pin-event-01
setp sendkeys.0.pin-event-01-1
setp sendkeys.0.pin-event-01-2
setp sendkeys.0.pin-event-01-3
(for no shift, shift 1, shift 2 and both shifts)
I would also add a scancode (negative?) to set the shift bits from the keyboard. (and bidirectional bits in HAL to show or set status)

the process takes up a lot of resources

 
Maybe add a delay to the main loop  (nanosleep (&tw, &tr)?
ps
nanosleep((const struct timespec[]){{0, 5000L}}, NULL);
reduced CPU load to 3-4% (vs ~50% )

I am trying to use sendkeys with matrix_kb component. (No board 7i73)
Are there any restrictions on the number of rows in the component matrix_kb?
For example is a 9x7s  configuration possible ?

When I set up my martrix_kb, I got the impression that not many people use it, so it is possible no one has tested a matrix such as 9x7. Try it. LinuxCNC will soon tell you if it doesn't like a result.
If you need a worked example, my HAL has a 5x5 matrix, It gets created in my HAL, and then used in my Postgui Hal. Both can be found attached to the first couple of posts in this thread.
forum.linuxcnc.org/12-milling/33035-retr...-maho-mh400e?start=0

The fact of the matter is that I tried to use 9x7s. 8 rows Ok, and the ninth does not work.