TMS320F28335, TMS320F28334, TMS320F28332TMS320F28235, TMS320F28234, TMS320F28232SPRS439H–JUNE 2007–REVISED MARCH 20106.4.1Reducing Current ConsumptionThe 2833x/2823x DSCs incorporate a method to reduce the device current consumption. Since eachperipheral unit has an individual clock-enable bit, reduction in current consumption can be achieved byturning off the clock to any peripheral module that is not used in a given application. Furthermore, any oneof the three low-power modes could be taken advantage of to reduce the current consumption evenfurther.Table 6-3indicates the typical reduction in current consumption achieved by turning off the clocks.Table 6-3. Typical Current Consumption by VariousPeripherals (at 150 MHz)(1)PERIPHERALIDDCURRENTMODULEREDUCTION/MODULE (mA)(2)ADC8(3)I2C2.5eQEP5ePWM5eCAP2SCI5SPI4eCAN8McBSP7CPU - Timer2XINTF10(4)DMA10FPU15(1)All peripheral clocks are disabled upon reset. Writing to/reading fromperipheral registers is possible only after the peripheral clocks areturned on.(2)For peripherals with multiple instances, the current quoted is permodule. For example, the 5 mA number quoted for ePWM is for oneePWM module.(3)This number represents the current drawn by the digital portion ofthe ADC module. Turning off the clock to the ADC module results inthe elimination of the current drawn by the analog portion of the ADC(IDDA18) as well.(4)Operating the XINTF bus has a significant effect on IDDIO current. Itwill increase considerably based on the following:•How many address/data pins toggle from one cycle to another•How fast they toggle•Whether 16-bit or 32-bit interface is used and•The load on these pins.
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Serial Peripheral Interface Bus, Texas Instruments Incorporated, TMS320F28335