1. 9/20/6Lecture 21 -PIC Architecture1 PIC Architecture

2. 9/20/6Lecture 21 -PIC Architecture2 PIC Architecture  Will now look at another architecture  Look at the microcontroller company  Step 1 – The programmers model

3. 9/20/6Lecture 21 -PIC Architecture3 Philosophy of PIC Architecture  Embedded processing is pervasive  Electronic intelligence in is everyday products  Company Philosophy Have products that fit the problem Many systems can be automated using 8-bit microcontrollers Much of product line is 8-bit

4. 9/20/6Lecture 21 -PIC Architecture4 Reasons for pervasiveness?  Competitive pressure  Expanded functionality of products  Provide differentiation in product from that of competitor  Cost competitive integrated solution  Allow creation of new classes of products

5. 9/20/6Lecture 21 -PIC Architecture5 Microcontroller Solution  Microcontroller features CPU – processing unit Non-volatile program memory Re-settable non-volatile data memory (EEPROM) RAM for data storage Direct support for various input/output

6. 9/20/6Lecture 21 -PIC Architecture6 Some typical applications  Automotive air bag systems  Remote control  Handheld tools  Appliances – coffee pot, mixer, stove, refrigerator, dish washer, washer, dryer  Major home systems – heating and cooling  Cordless phones and cell phones  Security systems  TV, DVD player/recorder, DVR, PVR  Sound system

7. 9/20/6Lecture 21 -PIC Architecture7 Come in 4-bit through 32-bit  4-bit Very inexpensive  8-bit Still very cheap – often ~$1.00 per chip  16 and 32 bit Priced at $6.00 to 12.00 each  Evaluation of requirements, chip capability, and cost come into design decision

8. 9/20/6Lecture 21 -PIC Architecture8 Typical automotive use  Engine control – 32-bit microcontroller Fuel flow, fuel mixture, valve timing, throttle body opening, spark timing  Transmission control –16-bit microcontroller  Audio system – 16-bit  Antilock braking – 16-bit  Up to fifty 8-bit microcontrollers for functions of Wiper control Electric Mirrors Air Bags

9. 9/20/6Lecture 21 -PIC Architecture9 Automotive today continued  Up to fifty 8-bit microcontrollers for functions of Wiper control Electric Mirrors Air Bags Fuel pump Speedometer Security system Climate control system Power windows …..

10. 9/20/6Lecture 21 -PIC Architecture10 Microchip’s position

11. 9/20/6Lecture 21 -PIC Architecture11 Microchip and microcontroller use

12. 9/20/6Lecture 21 -PIC Architecture12 Microcontroller choice parameters  Number of I/O pins  Amount of program and data memory  Speed  Timer Resources  Interrupt control  Robustness  Error recovery – watchdog timers  Power, I/O expansion, math support

13. 9/20/6Lecture 21 -PIC Architecture13 Block Diagram

14. 9/20/6Lecture 21 -PIC Architecture14 PIC architecture is a “Harvard” architecture  The Harvard Architecture

15. 9/20/6Lecture 21 -PIC Architecture15 Feature of Harvard architecture  Near all instructions are single instruction word instructions Only one fetch per instruction  Instruction fetch and execute are pipelined so you can operate at near clock rate instructions per second  2 separate buses One for instructions and one for data

16. 9/20/6Lecture 21 -PIC Architecture16 PIC Instruction pipelining  What % of time does 1 st flow of execution occur??

17. 9/20/6Lecture 21 -PIC Architecture17 Frequency of Branches  On architectures such as the HP during the normal flow of a program’s execution on 8 to 12 instructions are executed before a branch occurs.  (aside) Modern architectures can easily achieve above 90% correct branch prediction.  This can be factored into actual “speed” of the processor.