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Microprocessor and Interfacing 261313

Microprocessor and Interfacing 261313. PIC Code Execution II. http://www.e-cpe.org/moodle. Memory Mapped I/O (MMIO). MOVWF 06. W. B0 B1 B2 B3 B4 B5 B6 B7. PIC. MOVLW XX MOVWF 06. PIC-C Trick: Port-level Control. #byte b_port = 6 // mem pointer

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Microprocessor and Interfacing 261313

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  1. Microprocessor and Interfacing261313 PIC Code Execution II http://www.e-cpe.org/moodle

  2. Memory Mapped I/O (MMIO) MOVWF 06 W

  3. B0 B1 B2 B3 B4 B5 B6 B7 PIC MOVLW XX MOVWF 06

  4. PIC-C Trick: Port-level Control #byte b_port = 6 // mem pointer b_port = 0xff; // drive port b

  5. ข้อดีข้อเสียของ Memory Mapped I/O ไม่ต้องออกแบบคำสั่งเฉพาะสำหรับ I/O I/O Operation MOVWF 06 MOVWF 21 Mem Operation

  6. ข้อดีข้อเสียของ Memory Mapped I/O ลดความซับซ้อนของ CPU ทำให้ราคาถูกลง และ ออกแบบได้ง่าย YES NO

  7. ข้อดีข้อเสียของ Memory Mapped I/O 128 Bytes I/O Mapped แต่ก็ต้องเสียตำแหน่งใน Memory ไปบางส่วน 240 Bytes Available RAM

  8. The 3 Gig not 4 Gig RAM Problem 4 GB?? 3 GB?? 32 bit

  9. The 3 Gig not 4 Gig RAM Problem Address Space ~1 GB 3 GB Video Card BIOS PCI Bus RAM (4 GB)

  10. ข้อดีข้อเสียของ Memory Mapped I/O ถ้า Memory และ I/O ใช้ data bus เดียวกัน อาจทำให้ Memory Access ช้าลง Slow I/O Operation MOVWF 06 MOVWF 21 Fast Mem Operation

  11. Port Mapped I/O (PMIO) • มี I/O Bus แยกจาก Memory Bus • ใช้คำสั่งแยกกัน

  12. Machine Code Generation Methods

  13. Options • Write Machine Code • Write Assembly Code • Use a High-Level Compiler

  14. Writing Machine Code ENIAC

  15. Drawbacks of High-Level Compilers • Poor optimization • Non-Optimal Hardware Utilization

  16. Poor Optimazation .................... while (1) { .................... output_b(i); 001A: BSF 03.5 001B: CLRF 06 001C: BCF 03.5 001D: MOVF 21,W 001E: MOVWF 06

  17. Poor Optimization Ex 2 .................... int i; .................... i = 5; 000D: MOVLW 05 000E: BCF 03.5 000F: MOVWF 21 .................... do { .................... i--; 0010: DECF 21,F .................... } while (i>0); 0011: MOVF 21,F 0012: BTFSS 03.2 0013: GOTO 010

  18. Non-Optimal HW Utilization RLF Equivalent Program in ASM BCF 03.5 MOVF 0x21,W MOVWF 06 RLF 0x21, F GOTO 0x1A

  19. File Register Map

  20. Status Register (Address 03)

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