【正文】 Fig. 2. Circuit Diagram. 10 3. Software Description The present work is implemented using ARM IAR Workbench IDE and the necessary embedded C program is developed and dumped into the embedded processor using Flash magic ISP Utility. The ARM IAR Workbench IDE is a very powerful Integrated Development Environment (IDE) that allows you to develop and manage plete embedded application projects. InSystem Programming is programming or reprogramming the onchip flash memory, using the bootloader software and a serial port. The LPC2387 microcontroller is based on a 16bit/32bit ARM7TDMIS CPU with realtime emulation that bines the microcontroller with 512 kB of embedded highspeed flash memory. A 128bit wide memory interface and unique accelerator architecture enable 32bit code execution at the maximum clock rate. For critical performance in interrupt service routines and DSP algorithms, this increases performance up to 30 % over Thumb mode. For critical code size applications, the alternative 16bit Thumb mode reduces code by more than 30 % with minimal performance LPC2387 is ideal for multipurpose serial munication applications. It incorporates a 10/100 Ether Media Access Controller (MAC), USB full speed device with 4 kB of endpoint RAM,four UARTs, two CAN channels, an SPI interface, two Synchronous Serial Ports (SSP), threeI2C interfaces, and an I2S interface. This blend of serial munications interfaces bined with an onchip 4 MHz internal oscillator, 64 kB SRAM, 16 kB SRAM for Ether, 16 kB SRAM for USB and general purpose use, together with 2 kB battery powered SRAM makes this device very well suited for munication gateways and protocol converters. Various 32bit timers, an improved 10bit ADC, 10bit DAC, one PWM unit, a CAN control unit, and up to 70 fast GPIO lines with up to 12 edge or level sensitive external interrupt pins make this microcontroller particularly suitable for industrial control and medical systems. The LPC2378 Microcontroller provides onchip bootloader software that allows programming of the internal flash memory over the serial channel. Philips provides a 11 utility program for InSystem programming called Flash magic Software. 4. Results and Conclusions Embedded ARM processor based automatic speed control DC motor fan is designed and test the validity of the design, the temperature sensor is kept inside a small oven and its temperature is increased beyond the room temperature. Now the fan is operated to run with full speed and the temperature is found to eback to normal temperature. This is repeated with various VLSI chips like Pentium processor, FPGA chips etc. Now the temperature sensor is kept very near to the Pentium processor of the puter and it is observed that, as the time lapses the speed of the fan is automatically increased and the temperature of the chip is found to be controlled. These results are displayed on LCD panel. Though the present system is working well in the given environment, still it is worthwhile to highlight the following conclusions. Normally, controlling fan speed or clock throttling based on temperature requires that the temperature of the high speed chip should be first measured. This is done by placing a temperature sensor close to the target chip either directly next to it or in some cases, under it or on the heat sink. The temperature measured in this way corresponds to that of the high spe