| 摘要 |
PURPOSE: A CPU operation condition setting system is provided to transmit digital value for setting the CPU operation condition so that it can vary a power mode setting of the CPU without increasing a pin count. CONSTITUTION: The system comprises a core chip set(20), a CPU(60), a mode select controller(40) and a serializer(41). The core chip set(20) receives a power mode switching request on the CPU(60), and transmits the digital value, corresponding to the requested power mode, to the mode select controller(40) via 4 GPO(General Purpose Register) output terminals(a-d) to enable 16 power modes to be set. The serializer(41), installed within the mode select controller(40), converts the received parallel digital values into serial bit frame signals based on a reference CPU clock generated from a clock generator(10). So the serializer(41) transmits the frame signal corresponding to the power mode to the CPU(60) via a single serial signal line. The CPU(60) makes a frame analyzer(61) receive the frame signal, extract 4 bit data signal from the frame signal, and check the a value of the extracted digital signal to determine a power mode of the CPU(60).
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