Some differences between microprocessors and microcontrollers MP: suited to contro of I/O devices requiring a minimum component count MC: suited to processing information in computer systems Instruction sets: MP: processing intensive powerful addressing modes instructions to perform complex operations & manipulate large volumes of data processing capability of MCs never approaches those of MPs large instructions -- e.g., 80X86 7-byte long instructions MC: cater to control of inputs and outputs instructions to set/clear bits boolean operations (AND, OR, XOR, NOT, jump if a bit is set/cleared), etc. Extremely compact instructions, many implemented in one byte (Control program must often fit in the small, on-chip ROM) Hardware & Instructionset support: MC: built-in I/O operations, event timing, enabling & setting up priority levels for interrupts caused by external stimuli MP: usually require external circuitry to do similar things (e.g, 8255 PPI, 8254 PIT, 8259 PIC) Bus widths: MP: very wide large memory address spaces (>4 Gbytes) lots of data (Data bus: 32, 64, 128 bits wide) MC: narrow relatively small memory address spaces (typically kBytes) less data (Data bus typically 4, 8, 16 bits wide) Clock rates: MP very fast (> 1 GHz) MC: Relatively slow (typically 10-20 MHz) since most I/O devices being controlled are relative
Posted on: Sat, 08 Mar 2014 05:58:41 +0000
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