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Memory Organization. Microprocessor and Interfacing 261313. CPU 8088 10 MHz 8/16 Bit 1M RAM. CPU 80486 66 MHz 32 Bit 8M RAM. Pentium 133 MHz 32 Bit 16M RAM. Pentium MMX 200 MHz 32 Bit 48M RAM. Pentium II 366 MHz 32 Bit 128M RAM. Pentium M 1.6 GHz 32 Bit
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Memory Organization Microprocessor and Interfacing261313
CPU 8088 10 MHz 8/16 Bit 1M RAM
CPU 80486 66 MHz 32 Bit 8M RAM
Pentium 133 MHz 32 Bit 16M RAM
Pentium MMX 200 MHz 32 Bit 48M RAM
Pentium II 366 MHz 32 Bit 128M RAM
Pentium M 1.6 GHz 32 Bit 512M RAM
Core2 Duo 2.0 GHz 32/64 Bit 4G RAM
MHz RAM CPU Bits
How many bits Is this PIC CPU?
ระบบ 32 Bit กำลังเจอทางตัน?
RAM ใหญ่ที่สุดที่ระบบ 32 bit มองเห็นมีค่าเป็นเท่าใด?
Memory Limit of 32bit Machines = 4 Giga Bytes
How to support bigger memory? 1.Upgrade to 64-bit systems 64-bit CPU 64-bit OS
Limitation of moving to 64-bit systems Need 64-bit Hardware Drivers Applications need to be re-compiled with a 64-bit compiler
How to support bigger memory? 2. Expand existing bits
วิธีแก้ปัญหาของ Intel Physical Address Extension (PAE) 4 bits 32 bits = 64 GB
PAE Support CPU with PAE (Since P-Pro) PAE Aware OS
Benefits of PAE • Backward Compatible Limitations • Taking advantage of the added memorystill requires changes in the software
สองเรื่องน่ารู้เกี่ยวกับหน่วยความจำของPIC Microcontroller
1. When Memory Grows Beyond Anticipation(เมื่อหน่วยความจำขยายโตเกินคาด)
1.1 การอ้างอิงตำแหน่งใน Flash Memory
K = 11 bit Maximum memory = 2^11 = 2K Bytes
PIC 16F877 has 8K Flash Memory: How do we access all of it? 7 0 PCLATH (F# 0x0A) Bit 3-4 in PCLATH are usedfor memory access Total Memory becomes 2^13 = 8K Bytes
7 0 Creating a 13 bit memory address 13 11 10 0 OPCODE CALL or GOTO k (Literal) PCLATH 12 10 0 13 Bit Memory Address
PIC Flash Memory is Divided in to 4 Pages of 2KBytes 12 10 0 2K 2K 2K 2K
Address 0x900 exceeds 11 bits 12 10 0 0x900 = 0 1 0 0 1 0 0 0 0 0 0 0 0 0x01 0x100
12 10 0 0x900 = 0 1 0 0 1 0 0 0 0 0 0 0 0 0x01 0x100