pzbcm_counter

pzbcm_counter

https://github.com/pezy-computing/pzbcm/tree/master/pzbcm_counter

Overview

This module implements a basic counter.

Parameters

name	type/width	default value
WIDTH	int	2
MAX_COUNT	WIDTH	all bits 1
MIN_COUNT	WIDTH	0
INITIAL_COUNT	WIDTH	MIN_COUNT
WRAP_AROUND	1	1

• WIDTH
  • Width of the count value.
• MAX_COUNT
  • Maximum value of the count value.
• MIN_COUNT
  • Minimum value of the count value.
• INITIAL_COUNT
  • Initial value of the count value.
• WRAP_AROUND
  • When this value is set to 1
    • The count value goes to MIN_VALUE when the count value is MAX_VALUE and i_up is asserted.
    • The count value goes to MAX_VALUE when the count value is MIN_VALUE and i_down is asserted.
  • When this value is set to 0
    • The count value is not incremented more when the count value is MAX_VALUE.
    • The count value is not decremented more when the count value is MIN_VALUE.

IO ports

name	direction	type/width	note
i_clk	input	1	clock
i_rst_n	input	1	reset (async/active low)
i_clear	input	1	the count value is reset to INITIAL_COUNT when this port is asserted
i_set	input	1	i_set_value is set to the count value when this port is asserted
i_set_value	input	WIDTH
i_up	input	1	the count value is incremented when this port is asserted
i_down	input	1	the count value is decremented when this port is asserted
o_count	output	WIDTH	current count value
o_count_next	output	WIDTH	count value for the next clock cycle
o_wrap_around	output	1	indicate the count value changes from MAX_VALUE to MIN_VALUE or from MIN_VALUE to MAX_VALUE