Transcript PCB design and fabrication

System on a Chip (SoC)
Lin Zhong
ELEC424, Fall 2010
Photolithography
1969
Ivan Sutherland won Turing Award in 1988 for his Ph.D. work in 1963
http://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-574.pdf
“System on board”
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“System on board” (Contd.)
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Multiple Chip Modules (MCM)
• Intel Pentium D, Core 2 Quad
IBM POWER5 (2004) MCM, used in IBM system p servers, four dual
core processors + four L3 caches
Wikipedia.org
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System in Package (SiP)
400MHz
32MB
Source: Intel.com
Siemens SX66 PDA Phone
Audiovox PPC6601KIT
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System-on-a-chip (SoC): TI OMAP
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System-on-a-chip (SoC): TI MSP430
Functional block diagram
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Inside a CPU (Micro-architecture)
IBM POWER5 die photo (2004)
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Sinharoy et al 2005
FXU: fixed-point execution unit
ISU: instruction sequencing unit
IDU: instruction decode unit
LSU: load/store unit
IFU: instruction fetch unit
FPU: floating-point unit
MC: memory controller
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Components of SoC
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Processors
Clock generator
Flash memory & controller
DMA & controller
Digital I/O modules
Programming interface
Interconnection
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Embedded processors
• Microprocessor (32bit beyond)
– ARM, MIPS, PowerPC, SuperH
– Usually very modern architectures
– ARM: Most popular 32bit embedded processor (75%)
• Assignment: read “ARM architecture” from Wikipedia
• Microcontroller (4-16bit)
– Harvard architecture
– 8051 (8bit), PIC (8bit), AVR from Atmel (8bit)
– MSP430: 16-bit RISC, von Neumann architecture
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Clock generator
• Resonant circuit + amplifier
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Res
• Resonant circuit (Oscillator)
– Crystal oscillator (>2x109/yr)
• ~10KHz to ~10MHz
• Quartz, ceramics (low cost, low accuracy), surface acoustic
wave (SAW) quartz crystal (expensive, accurate)
• Real-time clocks
– 32.768KHz (215), 4.194304MHz (222)
• Application-specific
– 4.9152MHz (4 x 1.2288MHz, CDMA baseband frequency)……
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Oscillator (Contd.)
• LC/RLC circuit
• Ring oscillator
– Application other than oscillator?
• Voltage-controlled oscillator (VCO)
– Varicap: variable capacitance diode (tuning diode)
– Phase-locked loop for high-speed clock (next slide)
– Frequency scaling of IC for energy saving
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Phase-locked loop (PLL)
• High-speed clock from a master oscillator
• Digital PLL
Master
oscillator
Phasefrequency
detector
voltage
VCO
Frequency
divider (N)
• Clock generation, recovery, synchronization
– Digital computing, RF communication
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MSP430 clock modules
• Clock sources
– External oscillators
• Low- oscillator (LFXT1CLK): usually 3.2768KHz (RTC)
• Optional high-frequency oscillator (XT2CLK)
– Internal digitally controlled oscillator (DCO) (DCOCLK) (power
hungry)
• Clock signals
– Auxiliary clock: divided LFXT1CLK (1, 2, 4, 8)
• For low-power standby
– Master clock: any source, divided by 1, 2, 4, or 8
– Sub-system clock: XT2CLK or DCOCLCK, divided by 1, 2, 4, or 8
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DCO (Contd.)
• Ring oscillator with RC-type characteristics
• Software controllable
– On/Off
– Frequency
8 internal and 1 external
resistors
– External resistor allows low temperature impact, higher
frequency
• Impacted by temperature , supply voltage, and process
variations (inter-chip variations)
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Flash Memory and Controller
• Non-volatile, semiconductor memory
– Limited # of erase cycles  wear leveling
• NOR Flash: slow write/erase, random access
– ROM replacement
• NAND Flash: faster write/erase, block access,
denser, more enduring
– Harddisk replacement
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MSP430 Flash memory controller
• NOR flash (for program)
– No need for wear leveling (100K to 1M erase cycles)
• In-system programmable (ISP)
– Self programming, program via wireless
• Programming through JTAG, UART (Bootstrap loader,
BSL)
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Digital I/O Modules
• USART
– Universal synchronous/asynchronous
receiver/transmitter
– Asynchronous: UART
– Synchronous: SPI, I2C
• UART (2-4 wires)
– Easily work with RS-232 (serial port), modem,
Bluetooth (Serial Port Profile)
– Baud rate, # of data bits, optional parity bit, flow
control
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MSP430 UART
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Two UART ports, each two pins
Support interrupt
No hardware flow control
<200Kbps
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Serial interfaces
• Inter-Integrated Circuit (I2C)
– Two wires
– Standard mode: 100Kbps
– Fast mode: 400Kbps
– System management bus (SMBus): 100Kbps
• Serial Peripheral Interface (SPI)
– 4 wires: Clock, Chip Select, In and Out
– Low-megahertz data rate
wikipedia.org
Universal Serial Bus (USB)
• Replacing all serial/parallel ports
– All phones in China use USB for power
• Host vs. device
• USB 1.0: low-speed, 1.5Mbps
– Human interface devices
– 1.5A power supply
– USB 1.1: full-speed, 12bBps
• USB 2.0: high-speed, 480Mbps
– Storage devices, Wi-Fi cards etc.
– 900mA power supply
• USB 3.0: super-speed, 4.8Gbps
Analog I/O
• Analog-digital conversion (ADC)
– Voltage measurement
– Sensing the world through voltage
• XXX  voltage
• Digital-analog conversion (DAC)
– Actuator
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ADC
• Resolution: how many bits for “D”?
– 24bits max
– MSP4301611: 12 bits
• Sampling rate: how fast?
– MSP430: up to 200Ksps
• Accuracy
– Quantization error etc.
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Interrupt
• Polling vs. interrupt
• Non-maskable vs. maskable
Save context
Interrupt
handler
• Nested interrupt
Retrieve
context
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Interrupt
• Programmable interrupt controller (PIC)
– Prioritizing multiple sources
– Offloading the CPU
Interrupt sources (external
devices)
Interrupt
PIC
CPU
Interrupt vector
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Exceptions, signals, & interrupts
• Exceptions
– Any disruption of normal execution to execute
special instructions
• Signals
– Inter-process communication
• Interrupt
– Asynchronous exception introduced by external
hardware
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Timer
• Count time
– Keep time
• How many cycles have elapsed
– Measure time
• Whether a given period of time elapsed
• Generate interrupt
Clock
Capture register
Interrupt
Comparator
Compare register
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Direct memory access (DMA)
• Free CPU from data transfer
• Multiple channels, master bus, interrupt CP when done
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DMA (Contd.)
• Character mode
• Block mode
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Power-saving mechanisms
• Frequency scaling (slow down)
– DCO
• Power saving modes
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Miscellaneous
• Pulse-width modulation (PWM)
– Applications: power delivery (charging, light, motor), sound
synthesis
• Watchdog timer
– Reset system under fault
• Brownout reset
– Reset system when supply voltage low
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