8051 block diagram
- 2. 2 Microcontroller: • A smaller computer • On-chip RAM, ROM, I/O ports... • Example：Motorola’s 6811, Intel’s 8051, Zilog’s Z8X and PIC 16X RAM ROM I/O Port Timer Serial COM Port Microcontroller CPU A single chip
- 3. 3 Microprocessor vs Microcontroller 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. • expensive • 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
- 4. 4 Microcontroller’s internal Blocks • CPU ( ALU, Registers, Oscillator/clock, Bus control) • RAM /Data memory • ROM / program memory • I/O ports • Timer/counters • Serial ports • Interrupts
- 5. Microcontroller Block Diagram CPU On-chip RAM On-chip ROM for program code 4 I/O Ports Timer 0 Serial PortOSC Interrupt Control External interrupts Timer 1 Timer/Counter Bus Control TxD RxDP0 P1 P2 P3 Address/Data Counter Inputs
- 6. 6 Microcontroller Block Diagram ALU Internal ROM I/O Ports Internal RAM Accumulator Registers Program Counter Stack Pointer Oscillator Counter/Timer Serial Port Interrupt Logic Bus Control
- 8. Program Counter and Data pointer Program Counter (PC): Program counter is a 16 bit Register. It holds the address of the next instruction to be executed. It does not have internal address (PC is the only register not having the internal address) Data Pointer (DPTR): DPH and DPL DPTR is used to furnish memory address for internal and external code access and external data access
- 9. A and B CPU Registers • A and B registers are the two registers among the 34 general purpose registers • Holds results of many instructions, particularly math and logical operations • A register (Accumulator) is the most versatile and is used for many operations including addition, subtraction, integer multiplication and division and Boolean bit manipulations • A register is also used for all data transfer between 8051 and any external memory • B register is used with A register for multiplication and division operations.
- 10. Flags and Program Status Word (PSW)
- 13. 8051 µC Hardware