soc design lecture 4 bus and amba introduction. youpyo hong, dgu road without traffic lights 2
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YOUPYO HONG, DGU
Two Types of Connections
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Point-to-Point Connection Common Bus-based Connection
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YOUPYO HONG, DGU
Bus
A subsystem that transfers data or signals between digital components .
Unlike a point-to-point connection, a bus can connect multiple components over the same set of wires.
Each bus defines its set of signals to physically connect components together.
The definition of the signals implicitly include the protocols on how to use the signals.
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YOUPYO HONG, DGU
First Generation Bus
A bundles of wires connected to CPU pins directly.
Memory and other devices are added to the bus using the same address and data pins as the CPU itself in parallel.
Drawbacks All component must have same clock -> limited clock
frequency CPU is busy due to heavy bus transactions. -> low
throughput. Examples : Early IBM PCs in 1980s.
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YOUPYO HONG, DGU
Second Generation Bus
Separated the system into two "worlds", the CPU and memory on one side, and the various devices on the other, with a bus controller in between.
CPU can now be free from slow peripheral bottleneck.
Shortcomings A lot of bus controllers (for each slot in a computer.)
Examples : SCSI, IDE
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YOUPYO HONG, DGU
Widely Known Buses
Parallel Industry Standard Architecture or ISA Advanced Technology Attachment or ATA (aka PATA, IDE, EIDE,
ATAPI, etc.) disk peripheral attachment bus Peripheral Component Interconnect or PCI PC card, previously known as PCMCIA, SCSI Small Computer System Interface (disk peripheral attachment)
Serial 1-Wire HyperTransport I²C PCI Express or PCIe Serial Peripheral Interface Bus or SPI bus USB Universal Serial Bus
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YOUPYO HONG, DGU
Bus for SOC
SOC needs a bus, of course. SOC bus should support
Modular system designTechnology-independence Easy to useLight in size and complexity
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YOUPYO HONG, DGU
AMBA
Stands for Advanced Microcontroller Bus Architecture
Developed by ARM in 1990s (England) ARM also developed ARM RISC series for
SOC applications. ARM is now the mostly widely used RISC
core and that makes AMBA most popular BUS in SOC world.
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