Rebinding keys to different keys

Note that there is a fake keyboard matrix in the emulated colecovision:

// The hardware consists of 2 controllers that each have 2 triggers
// and a 12-key keypad. They're not actually connected in a matrix,
// but a ghosting-free matrix is the easiest way to model it in openMSX.
//
// row/bit  7     6     5     4     3     2     1     0
//       +-----+-----+-----+-----+-----+-----+-----+-----+
//   0   |TRIGB|TRIGA|     |     |LEFT |DOWN |RIGHT| UP  |  controller 1
//   1   |TRIGB|TRIGA|     |     |LEFT |DOWN |RIGHT| UP  |  controller 2
//   2   |  7  |  6  |  5  |  4  |  3  |  2  |  1  |  0  |  controller 1
//   3   |     |     |     |     |  #  |  *  |  9  |  8  |  controller 1
//   4   |  7  |  6  |  5  |  4  |  3  |  2  |  1  |  0  |  controller 2
//   5   |     |     |     |     |  #  |  *  |  9  |  8  |  controller 2
//       +-----+-----+-----+-----+-----+-----+-----+-----+

This information can be used to use keymatrixdown/keymatrixup commands in a binding.

For example, to bind A to trigger 1 of controller 1:

bind A "keymatrixdown 0 64"
bind A,release "keymatrixup 0 64"

Ok that makes sense but how do you go about getting the keycodes how did you know to use 0 64? is there a list of keycodes I can download. Wait is that table you posted the key codes I having trouble understanding it, I’m guessing the 0 comes from row 0 but were does the 64 come from?

I’m afraid you’ve lost me how do you get 2^6 from 6? Is it that the bit is always 2 raised to the power of the bit. seems to be the case since i tried

bind KP7 "keymatrixdown 2 2"
bind KP7,release "keymatrixup 2 2"

and it worked to rebind Coleco-numbad1 to numbad7. But why do it like that wouldn't be easier to have the numbers be the bit number?