ATMega chip full datasheet - UCSD Department of Physics

ATmega48A/PA/88A/PA/168A/PA/328/P30.1.3 ATmega48A: Supply Current of IO ModulesThe tables and formulas below can be used to calculate the additional current consumption forthe different I/O modules in Active and Idle mode. The enabling or disabling of the I/O modulesare controlled by the Power Reduction Register. See ”Power Reduction Register” on page 43 fordetails.Table 30-1.PRR bitATmega48PA: Additional Current Consumption for the different I/O modules(absolute values)Typical numbersV CC = 2V, F = 1MHz V CC = 3V, F = 4MHz V CC = 5V, F = 8MHzPRUSART0 2.9uA 20.7uA 97.4uAPRTWI 6.0uA 44.8uA 219.7uAPRTIM2 5.0uA 34.5uA 141.3uAPRTIM1 3.6uA 24.4uA 107.7uAPRTIM0 1.4uA 9.5uA 38.4uAPRSPI 5.0uA 38.0uA 190.4uAPRADC 6.1uA 47.4uA 244.7uATable 30-2.PRR bitATmega48PA: Additional Current Consumption (percentage) in Active and IdlemodeAdditional Current consumptioncompared to Active with externalclock (see Figure 30-48 on page358 and Figure 30-49 on page358)PRUSART0 1.8% 11.4%PRTWI 3.9% 20.6%PRTIM2 2.9% 15.7%PRTIM1 2.1% 11.2%PRTIM0 0.8% 4.2%PRSPI 3.3% 17.6%PRADC 4.2% 22.1%Additional Current consumptioncompared to Idle with externalclock (see Figure 30-53 on page360 and Figure 30-54 on page361)It is possible to calculate the typical current consumption based on the numbers from Table 30-2on page 338 for other V CC and frequency settings than listed in Table 30-1 on page 338.30.1.3.1 ExampleCalculate the expected current consumption in idle mode with TIMER1, ADC, and SPI enabledat V CC = 2.0V and F = 1MHz. From Table 30-4 on page 363, third column, we see that we needto add 11.2% for the TIMER1, 22.1% for the ADC, and 17.6% for the SPI module. Reading fromFigure 30-53 on page 360, we find that the idle current consumption is ~0.028 mA at V CC = 2.0Vand F = 1MHz. The total current consumption in idle mode with TIMER1, ADC, and SPI enabled,gives:ICCtotal ≈0.028 mA ⋅ (1 + 0.112 + 0.221 + 0.176) ≈0.042mA8271D–AVR–05/11338