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Processor and Memory Organisation. By: Prof. Mahendra B. Salunke Asst. Prof., Department of Computer Engg, SITS, Pune-41. Email: msalunke@gmail.com URL: microsig.webs.com. Contents. Structural unites in a processor Processor selection for an embedded system Memory devices
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Processor and Memory Organisation By: Prof. Mahendra B. Salunke Asst. Prof., Department of Computer Engg, SITS, Pune-41 Email: msalunke@gmail.com URL: microsig.webs.com
Contents • Structural unites in a processor • Processor selection for an embedded system • Memory devices • Memory selection for an embedded system • Direct memory access (DMA) • Interfacing processor, memories and I/O devices
MAR: Memory Address Register MDR: Memory Data Register Internal bus Address bus Data bus Control bus BIU: Bus Interface Unit IR: Instruction Register ID: Instruction Decoder CU: Control Unit ARS: Application Register Set ALU: Arithmetic Logical Unit PC: Program Counter Structural units in a processor
SRS: System Register Set SP: Stack Pointer IQ: Instruction Queue PFCU: Prefetch Control Unit I-Cache: Instruction cache BT-Cache: Branch Target Cache D-Cache: Data Cache MMU: Memory Management Unit FLPU: Floating Point Processing Unit FRS: Floating Point Register Unit Advanced Processing Units AOU: Atomic Operation Unit Structural units in a high performance processors
Instruction Cycle Time Internal Bus Width CISC or RISC PC bits and its reset value SP bits and its initial reset value Pipelined and Superscalar Units On-chip memories External Interrupts Interrupt Controller Bit manipulation Instructions Floating Point Processor DMA Essential Characteristics to Consider during processor selection
Processor Specific Features • Big-endian mode and little-endian mode • Burst mode memory access • Architecture: Harvard / Princeton • I/O address space • Atomic operations
Memory devices • ROM: • Masked ROM • EPROM • EEPROM • Flash Memory • PROM (OTP ROM) • RAM: • SRAM • DRAM: EDO RAM, SDRAM, RDRAM, Parameterized Distributed RAM, Parameterized Block RAM
Memory selection for an embedded system • Simple systems like automatic chocolate vending machine or robot needs no external memory • The data acquisition system needs EEPROM or flash • A mobile phone system needs 1MB plus RAM and 32kB plus EEPROM or flash device. • Image / voice / video recording systems require a large flash memory So designer selects the processor and memory bases on system’s requirements.
Direct memory access (DMA) • The DMA is required when a multi-byte data set or a block of data is to be transferred between two systems without the CPU intervention, except at the start and at the end. • Modes of operations: • Single transfer • Burst transfer • Bulk transfer
Interfacing processor, memories and I/O devices • An interfacing circuit consists of decoders and demultiplexers and is designed as per available control signal and timing diagrams of the bus signals. • This circuit connects all the units, processor, memory devices and the IO devices. • It is a part of the glue circuit used in the system and is in a GAL or FPGA.
Happy Learning Contact Details: Email: msalunke@gmail.com URL: microsig.webs.com