Debug print

You can see debug print on a "USB Serial Port" (so-called "COM Port" in Windows) that will be helpful if your keymap.rb doesn't work well:

Key	Value
Baud	115200
Data bits	8
Parity	None
Stop bits	1
Flow control	None

PicoRubyVM.print_alloc_stats

(Valid version: 0.9.14+)

PRK has a built-in method, PicoRubyVM.print_alloc_stats, which prints memory statistics of the PicoRuby virtual machine.

You can assign this method to a key as below:

kbd.add_layer :default, %i(STATS KC_A KC_B KC_C)
kbd.define_mode_key :STATS, [ Proc.new { PicoRubyVM.print_alloc_stats }, nil, 300, nil ]

Tapping STATS key shows current statistics in the serial console like this:

ALLOC STATS
 TOTAL 204800
 USED   67700
 FREE  136756
 FRAG      55

FRAG stands for the count of fragmentation. The other three values are in bytes.