ECE 765 Microcomputer StructuresECE 765单片机的结构.pptVIP

Lecture 3 - Instruction Set - Al Lecture 3 - Instruction Set - Al 9/20/6 Lecture 3 - Instruction Set - Al * The Hardware Interface 9/20/6 Lecture 3 - Instruction Set - Al * The Hardware Interface The 68000 Hardware Interface Chip Pins – group pins into classes Specifics of the classes – look at each class of pins in turn Some basic interfacing to those pins 9/20/6 Lecture 3 - Instruction Set - Al * Chip Interfaces Chip interface for a microprocessor Microprocessor chip is not stand alone To make it work must add Memory I/O interfaces Timing Other support pin connections that are processor specific Support pins like RESET 9/20/6 Lecture 3 - Instruction Set - Al * Microprocessors and microcontrollers What is the difference in a microprocessor and a microcontroller? Microprocessor – needs memory, I/O, and other support to operate. Microcontroller – almost stand alone Many have internal clock – can add an external crystal if desired but usually not required RAM and ROM on the chip (although limited in size) I/O on chip – often dual use for I/O and address/data to/from memory Minimal external support needed 9/20/6 Lecture 3 - Instruction Set - Al * The 68000 pinout 64 pin chip Pins can be placed into 3 categories System support Special purpose Usually device specific Memory and peripheral interface 9/20/6 Lecture 3 - Instruction Set - Al * System support pins Most are common to all microprocessor and microcontroller chips Power Supply 68000 has 2 each Vcc and GND pins (4 total) Why? Better on chip power distribution and thus, a more reliable chip. Less voltage drop to many points on the chip 9/20/6 Lecture 3 - Instruction Set - Al * System support pins - 2 Clock Single phase TTL-compatible signal All internal timing derived for this signal 68000 uses dynamic storage technique internally What is dynamic storage technique? VLSI technique that reduces the logic required and thus results in power savings Relies on the capacitive nature of CMOS VLSI 9/20/6 Lecture 3 - Ins