ModuleWare Reference Guide - Hornad

Sequential PartsConfigurable Counter (cntr)If the reset is synchronous, then at every enabled clk trigger (rising edge if clk_type = Rising;falling edge if clk_type = Falling):count= rst_val= din= count + 1= 0= count - 1= mcountif rst is active, elseif load = 1, elseif up_dn = 1 and count not equal to mcount, elseif up_dn = 1 and count = mcount, elseif up_dn = 0 and count not equal to 0otherwiseIf the reset is asynchronous:count = rst_valif rst is active (irrespective of the clk trigger)else at every enabled clk trigger (rising edge if clk_type = Rising; falling edge if clk_type =Falling):count= din= count + 1= 0= count - 1= mcountif load = 1, elseif up_dn = 1 and count not equal to mcount, elseif up_dn = 1 and count = mcount, elseif up_dn = 0 and count not equal to 0otherwisemax = 1= 1= 0if up_dn = 1 and count = mcountif up_dn = 0 and count = 0otherwiseFunction for Johnson counterIf max_count = 100...; mcount = max_count;else if max_count = 100... - 1 mcount = 1100....)If reset is synchronous, then at every enabled clk trigger (rising edge if clk_type = Rising;falling edge if clk_type = Falling):count= rst_val= din= {count, nmsb} > 1= mcountif rst is active, elseif load = 1, elseif up_dn = 1 and count not equal to mcount, elseif up_dn = 1 and count = mcount, elseif up_dn = 0 and count not equal to 0otherwisewhere nmsb is the NOT of the most significant bit of the output port count; nlsb is the NOT ofthe least significant bit of the output port count and mcount is the value derived frommax_count;If reset is asynchronous:count = rst_val if rst is active (irrespective of the clk trigger)182ModuleWare Reference Manual, Library Version 1.9September 18, 2008