Microcontroller – PIC – 4 PIC types PIC architecture

1. Microcontroller – PIC – 4PIC typesPIC architecture

2. PIC microcontroller • PICPeripheral Interface Controller • by Microchip Technology • These devices have been very successful in 8-bit microcontrollers. • Why?  Microchip Technology has continuouslyupgraded the device architecture and added needed peripherals to the microcontroller to suit customers' requirements. • The development tools [assembler and simulator] are freely available athttp://microchip.com

3. Low-end PIC architecture • have limited program/code memory • for applications requiring simple interface functions and small program & data memories • Some device nos. • 12C5XX16C5X 16C505

4. Mid-range PIC arc… • more number of peripherals, • more number of registers and • more data/program memory. • Some devices are • 16C6X16C7X 16F87X • Program memory type is indicated by alphabet: C = EPROM  OTM (one-time programmable) F = Flash  RC = Mask ROM [cheapest, burnt while IC fabrication]

5. UV-EPROM

6. Mem. vs. Pins vs. Versions

7. Compare 8-bit PIC arch. • Visit http://www.microchip.com/pagehandler/en-us/family/8bit/architecture/home.html

9. PIC CPU archi.

10. Baseline PIC® Microcontrollers

11. read • Simple 33 (12-bit wide) instruction set for ease of use and quick development • 2K word (3 KB) addressable program memory • 144 bytes RAM (max) • 2 level hardware stack • 1 (8-bit) file select register • Multiple product options and easy migration

12. Mid-range PIC

13. read • 35 (14-bit wide) instructions • 8K word (14 KB) addressable program memory • 46 bytes RAM (max) • 8 level hardware stack • 1 (9-bit) file select register • Hardware interrupt handling • Highly integrated feature set, including EEPROM, LCD, mTouch™ sensing solutions and serial communications

14. Enhanced Mid-Range PIC

15. read • 49 (14-bit wide) instructions • 32K word (56 KB) addressable program memory • 4KB RAM (max) • 16 level hardware stack • 2 (16-bit) file select registers • Hardware interrupt handling with content save • Advanced feature set, multiple serial communications and motor control capability

16. PIC18

17. read K series • Provides the highest performance with benchmark nanoWattXLP extreme low power consumption. • 83 (16-bit wide) powerful C-optimized • Up to 2 MB addressable program memory • 4KB RAM (max) • 32 level hardware stack • 1 (8-bit) file select register • Integrated 8x8 hardware multiply • Highest performance 8-bit architecture

18. Why PIC is popular? • Speed: Harvard Architecture, RISC architecture, 1 instruction cycle = 4 clock cycles. • Instruction set simplicity: The instruction set has 35 instructionsfor PIC16 (as opposed to 111 instructions for 8051).

19. Why PIC is popular?... • Power-on-reset and brown-out reset. • Brown-out-reset means when the power supply goes below a specified voltage (say 4V), it causes PIC to reset; hence malfunction is avoided.  • A watchdog timer (user programmable) resets the processor, if the software/program ever malfunctions and deviates  from its normal operation.

20. Why PIC is popular?... • PIC microcontroller has 4 optional clock sources. •   Low power crystal •   Mid range crystal •   High range crystal •   RC oscillator (low cost). • Programmable timers and on-chip ADC. • Up to 12 independent interrupt sources.

21. Why PIC is popular?... • EPROM/ • OTP[one-time programmable] ROM/ • Masked version/ • Flash memory option. • I/O port expansion capability. • Free assembler and simulator support from Microchip at www.microchip.com

22. PIC CPU archi.

23. PIC Memory Organization • has 13 bits of program/code memory address. • Hence it can address up to 8k [213=8192] of program memory. • The program counter is 13-bit. • PIC16C6X or 16C7X program memory is 2k or 4k. • While addressing 2k of program memory, only 11-bits are required. Hence two MSBsof the program counter are ignored. • Similarly, while addressing 4k of memory, 12 bits are required. Hence the MSBof the program counter is ignored. • 2^10 = 1024 2^11 = 2048 • 2^12=4096 2^13=8192 • 2^14=16384 … 2^16=65536

24. Data mem. / RAM Data memory (Register Files): • Data Memory akaRegister File. • Register File consists of two components. • General purpose register file (same as RAM). • Special purpose register file (similar to SFR in 8051: Special Function Registers (SFRs) of 128 bytes) – fixed & every microcontroller must have them • It consists of I/O ports and control registers  Recall registers of 8086 & compare

25. PIC18 has a max of 4096 bytes (4K) [2^12=4096]of data RAM space. • Size of special-purpose reg [SPR] is fixed • Size of general-purpose reg [GPR] varies from 256 B to 4096 B. • GPR is divided into banks of 256B each [more – ch.6]

26. Data mem map

27. PIC18 – I/O pins • Can have from 16 to 72 pins – dedicated for I/O [more ch. 4]

28. PIC18 - peripherals • All PIC18 family have the following standard peripherals – • ADC • Timers • USART [universal synchronous asynchronous receiver transmitter] – it allows us to connect the PIC18-based system to serial ports (e.g., COM port of the IBM PC)

29. PIC µC peripherals CAN- (Controller Area Network), LIN- (Local Interconnect Network), USB- (Universal Serial Bus), I²C- (Inter-Integrated Circuit), SPI- (Serial Peripheral Interface), Serial or Ethernet Interface ADC - Analog Digital Converter USART- Universal Synchronous Asynchronous Receiver Transmitter

30. Courtesy – • http://microchip.com • ‘PIC Microcontroller and Embedded Systems, by MA Mazidi et al., Pearson, 2012