Tài liệu Microcontroller 8051 ppt

1 2 Why do we need to learn Microprocessors/controllers? • The microprocessor is the core of computer systems. • Nowadays many communication, digital entertainment, portable devices, are controlled by them. • A designer should know what types of components he needs, ways to reduce production costs and product reliable. 3 Different aspects of a microprocessor/controller • Hardware :Interface to the real world • Software :order how to deal with inputs 4 The necessary tools for a microprocessor/controller • CPU: Central Processing Unit • I/O: Input /Output • Bus: Address bus & Data bus • Memory: RAM & ROM • Timer • Interrupt • Serial Port • Parallel Port 5 CPU General- Purpose Micro- processor RAM ROM I/O Port Timer Serial COM Port Data Bus Address Bus General-Purpose Microprocessor System Microprocessors: • CPU for Computers • No RAM, ROM, I/O on CPU chip itself • Example ： Intel’s x86, Motorola’s 680x0 Many chips on mother’s board General-purpose microprocessor 6 RAM ROM I/O Port Timer Serial COM Port Microcontroller CPU • A smaller computer • On-chip RAM, ROM, I/O ports • Example ： Motorola’s 6811, Intel’s 8051, Zilog’s Z8 and PIC 16X A single chip Microcontroller : 7 Microprocessor • CPU is stand-alone, RAM, ROM, I/O, timer are separate • designer can decide on the amount of ROM, RAM and I/O ports. • expansive • versatility • general-purpose Microcontroller • CPU, RAM, ROM, I/O and timer are all on a single chip • fix amount of on-chip ROM, RAM, I/O ports • for applications in which cost, power and space are critical • single-purpose Microprocessor vs. Microcontroller 8 • Embedded system means the processor is embedded into that application. • An embedded product uses a microprocessor or microcontroller to do one task only. • In an embedded system, there is only one application software that is typically burned into ROM. • Example ： printer, keyboard, video game player Embedded System 9 1. meeting the computing needs of the task efficiently and cost effectively • speed, the amount of ROM and RAM, the number of I/O ports and timers, size, packaging, power consumption • easy to upgrade • cost per unit 2. availability of software development tools • assemblers, debuggers, C compilers, emulator, simulator, technical support 3. wide availability and reliable sources of the microcontrollers. Three criteria in Choosing a Microcontroller 10 Block Diagram CPU On-chip RAM On-chip ROM for program code 4 I/O Ports Timer 0 Serial Port OSC Interrupt Control External interrupts Timer 1 Timer/Counter Bus Control TxD RxD P0 P1 P2 P3 Address/Data Counter Inputs [...]... 2.5(A13 P2.4(A12 ) P ) 2.3(A11) P2.2(A10) P2.1(A9) P2.0(A8)  12 Packing Types of 8051 • The 8051 family members come in different packages, such as DIP （ dual in-line package ） ,QFP （ quad flat package ） and LLC （ leadless chip carrier ） – See Appendix H （ Pages 427-429 ） • They all have 40 pins • Figure 4-1 8051 Pin Diagram 13 8051 Pin Diagram PDIP/Cerdip P1.0 P1.1 P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 RST (RXD)P3.0... between XTAL and the machine cycle  15 Pins of 8051 （ 2/4 ） • RST （ pin 9 ）： reset – It is an input pin and is active high （ normally low ） • The high pulse must be high at least 2 machine cycles – It is a power-on reset • Upon applying a high pulse to RST, the microcontroller will reset and all values in registers will be lost • Reset values of some 8051 registers  – Way 1 ： Power-on reset circuit... of 8051 （ 4/4 ） • ALE （ pin 30 ）： address latch enable – It is an output pin and is active high – 8051 port 0 provides both address and data – The ALE pin is used for de-multiplexing the address and data by connecting to the G pin of the 74LS373 latch • I/O port pins – The four ports P0, P1, P2, and P3 – Each port uses 8 pins – All I/O pins are bi-directional 18 Figure 4-2 (a) XTAL Connection to 8051. ..11 Pin Description of the 8051 P1.0 P1.1 P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 RST (RXD)P3.0 (TXD)P3.1 (INT0)P3.2 (INT1)P3.3 (T0)P3.4 (T1)P3.5 (WR)P3.6 (RD)P3.7 XTAL2 XTAL1 GND 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 8051 (8031) 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 Vcc P0.0(AD0 P0.1(AD1) ) P0.2(AD2... registers  – Way 1 ： Power-on reset circuit  – Way 2 ： Power-on reset with debounce  16 Pins of 8051 （ 3/4 ） • /EA （ pin 31 ）： external access – There is no on-chip ROM in 8031 and 8032 – The /EA pin is connected to GND to indicate the code is stored externally – /PSEN ＆ ALE are used for external ROM – For 8051, /EA pin is connected to Vcc – “/” means active low • /PSEN （ pin 29 ）： program store enable... XTAL2 XTAL1 GND 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 8051 (8031) 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 Vcc P0.0(AD0 ) 0.1(AD1) P P0.2(AD2 ) 0.3(AD3) P P0.4(AD4) P0.5(AD5) P0.6(AD6) P0.7(AD7) EA/VPP ALE/PROG PSEN P2.7(A15) P2.6(A14) P2.5(A13) P2.4(A12) P2.3(A11) P2.2(A10) P2.1(A9) P2.0(A8) 14 Pins of 8051 （ 1/4 ） • Vcc （ pin 40 ）： – Vcc provides supply voltage to the... Table 4-1: RESET Value of Some 8051 Registers Register Reset Value PC 0000 ACC 0000 B 0000 PSW 0000 SP 0007 DPTR 0000 RAM are all zero  22 Figure 4-3 (a) Power-On RESET Circuit Vcc + 10 uF 31 30 pF 8.2 K 30 pF 11.0592 MHz 19 18 EA/VPP X1 X2 9 RST  23 Figure 4-3 (b) Power-On RESET with Debounce Vcc 31 10 uF 30 pF 9 EA/VPP X1 X2 RST 8.2 K  24 Pins of I/O Port • The 8051 has four I/O ports – Port 0... Internal CPU bus D Write to latch Clk Q 1 P1.X pin P1.X Q 0 2 output pin is Vcc M1 output 1 TB1 Read pin 8051 IC 30 Writing “0” to Output Pin P1.X Read latch Vcc TB2 Load(L1) 1 write a 0 to the pin Internal CPU bus D Write to latch Clk Q 0 P1.X pin P1.X Q 1 2 output pin is ground M1 output 0 TB1 Read pin 8051 IC 31 Port 1 as Output （ Write to a Port ） • Send data to Port 1 ： MOV A,#55H BACK: MOV P1,A ACALL... pin=High P1.X pin M1 TB1 Read pin 3 Read pin=1 Read latch=0 Write to latch=1 8051 IC 34 Figure C-12 Reading “Low” at Input Pin Read latch Vcc TB2 1 write a 1 to the pin 2 MOV A,P1 Load(L1) MOV P1,#0FFH Internal CPU bus D Write to latch Clk Q 1 0 P1.X Q 0 external pin=Low P1.X pin M1 TB1 Read pin 3 Read pin=1 Read latch=0 Write to latch=1 8051 IC 35 Port 1 as Input （ Read from Port ） • In order to make P1 an... the external pin) – P1 as an input port (i.e., read pin data into CPU bus) 26 A Pin of Port 1 Read latch TB2 Vcc Load(L1) Internal CPU bus D Write to latch Clk P1.X pin Q P1.X Q M1 TB1 P0.x Read pin 8051 IC 27 Hardware Structure of I/O Pin • Each pin of I/O ports – Internal CPU bus ： communicate with CPU – A D latch store the value of this pin • D latch is controlled by “Write to latch” – Write to . 8051 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 P1.0 P1.1 P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 RST (RXD)P3.0 (TXD)P3.1 (T0)P3.4 (T1)P3.5 XTAL2 XTAL1 GND (INT0)P3.2 (INT1)P3.3 (RD)P3.7 (WR)P3.6 Vcc P0.0(AD0 ) P0.1(AD1) P0.2(AD2 ) P0.3(AD3) P0.4(AD4) P0.5(AD5) P0.6(AD6) P0.7(AD7) EA/VPP ALE/PROG PSEN P2.7(A15) P2.6(A14 ) P2.5(A13 ) P2.4(A12 ) P2.3(A11) P2.2(A10) P2.1(A9) P2.0(A8) 8051 (8031)  13 Packing Types of 8051 • The 8051 family members come in different packages, such. critical • single-purpose Microprocessor vs. Microcontroller 8 • Embedded system means the processor is embedded into that application. • An embedded product uses a microprocessor or microcontroller