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Altera_Forum
Honored Contributor
10 years agoI checked the I/O settings. The only warning was on missing slew rate and drive strenght on the single output of the circuit. I explicitly set these and repeated the analysis obtaining no changes on the result.
Below a report that compares the I/O settings on the two circuits. I don't see any difference! Circuit A Pin Name/Usage : Location : Dir. : I/O Standard : Voltage : I/O Bank : User Assignment ------------------------------------------------------------------------------------------------------------- Din : M11 : input : 2.5 V : : 4 : Y reset : J6 : input : 2.5 V : : 3A : Y clk : J7 : input : 2.5 V : : 3A : Y Dout : B11 : output : 2.5 V : : 7 : Y Slew rate set to 2 and drive strength set to 16mA Signal activities Toggle rate (mil trans/sec) Toggle rate data source static probability static probability data source Din Input 0.031 simulation(f1) 0.557 simulation (f1) reset Input 0.001 simulation(f1) 0.000 simulation (f1) clk Input 199.999 simulation(f1) 0.5 simulation (f1) Dout Output 0.031 simulation(f1,f1) 0.407 simulation (f1,f1) Simulation (f1, f1) *** Circuit B Pin Name/Usage : Location : Dir. : I/O Standard : Voltage : I/O Bank : User Assignment ------------------------------------------------------------------------------------------------------------- Din : M11 : input : 2.5 V : : 4 : Y reset : J6 : input : 2.5 V : : 3A : Y clk : J7 : input : 2.5 V : : 3A : Y Dout : B11 : output : 2.5 V : : 7 : Y Slew rate set to 2 and drive strength set to 16mA Signal activities Toggle rate (mil trans/sec) Toggle rate data source static probability static probability data source Din Input 0.031 simulation(f1) 0.557 simulation (f1) reset Input 0.001 simulation(f1) 0.000 simulation (f1) clk Input 200 simulation(f1) 0.5 simulation (f1) Dout Output 0.031 simulation(f1,f1) 0.407 simulation (f1,f1) Simulation (f1, f1) I wonder if there's a formula to calculate the I/O power. It should be something like P= 0.5 * C_pin * (Vdd_pin^2)*fclk * switching_activity + Vdd_pin* I_pin_static. Are these values available somewhere?