The basics of digital circuits - galaxy.agh.edu.pl
Transcript of The basics of digital circuits - galaxy.agh.edu.pl
BASIC BOOLEAN
OPERATIONS
AND, conjunction, Boolean product
X A B AB A B A B
OR, disjunction, Boolean sum
X A B A B A B
/ 'X A A A
NOT, negation, complement
The basics of digital circuits
we need a better switch…
Logic gate – an electronic device that implements the Boolean operation (function)
7400 (74LS00, 74HCT00)
The basics of digital circuits
X
X
A B
A B
X AB AB
The basics of digital circuits
• conductors
• semiconductors
• insulators (dielectrics) Silicon Lattice
5.4Å
unit cell
(face-centered diamond cubic cell)
The basics of digital circuits
Metal Oxide Semiconductor Field Effect Transistor – MOSFET
The basics of digital circuits
inversion layer!
VGS low
VGS high
Metal Oxide Semiconductor Field Effect Transistor – MOSFET
approx. dimensions:
4.6x3.6mm
The basics of digital circuits
CMOS – Complementary Metal Oxide Semiconductor
taken from: www.physics.udel.edu/~watson/scen103/mos4.html
The basics of digital circuits
n-channel MOSFETp-channel MOSFET
Source Gate Drain
n-type substrate
Vin
Vout
Logical
HI ‘1’
Logical
LOW ‘0’
Logical
LOW ‘0’
Logical
HI ‘1’
AND gate
The basics of digital circuits
NOT (inverter)
Simplified,
taken from:
P. Horowitz
Art of Electronics
CMOS
f[Hz]
power
dissipation
[mW]
+ very low (near zero…) static (or at low frequencies) power dissipation
+ high noise margin
+ nearly ideal voltage transfer characteristics, comparable rising and falling times
+ high fan-out (number of gated connected to one output)
+ today: relatively cheap, robust and
- problems with power dissipation (e.g. heat) at (very) high frequencies (>GHz)
2P CU f
supply voltage
switching
frequency
load
capacitance
CMOS technology
pros & cons
The power wall…
The chip manufacturing process
Intel
a 45nm logic
technology
Intel
a 22nm logic technology (np. Ivy Bridge)
http://newsroom.intel.com/docs/DOC-2032
The further improvement of computational efficiency…
• further increase of clock frequency –>
increased power consumption & heat dissipation
• further reduction of supply voltage –> lower noise immunity, lower switching times,
voltage drops… etc…
Some technical problems can be solved using modern, dense manufacturing
processes…
• current trends:
• multicore processors & multiprocessor computers
• instruction-level parallelism
• coprocessors, (GP)GPU , Intel Xeon PHI…
Silicon die of the modern CPU (Intel i5-i7)
• total power dissipation 90- 130W
• a few (or over a dozen) BIG and UNIVERSAL cores…
Intel Kaby Lake (14nm, 2016)
Technology progress:
14nm -> 10nm -> 7-5nm (2019)
Intel, Samsung, TSMC (Taiwan Semiconductor Manufacturing Company)
Si lattice constant: ok. 5.4Å (0.54nm) !
source: Intel
Another approach…
several dozens (hundreds) of SIMPLE cores
e.g Intel Atom cores - Intel Kinghts Langing (Xeon Phi), built-in 16GB RAM
Intel i7
SUN UltraSPARC T3
IBM
Power
A2
IBM
Cell
Methods of designing digital circuits
• classical approach:
• determine all the necessary input signals and behaviour of outputs
• create the truth (or Karnough) tables for each output signal
• perform minimization and write final Boolean expressions
• draw appropriate schematic diagram
• Hardware Description Language (HDL) + Programmable Logic Device (CPLD/FPGA)
(Complex Programmable Logic Device / Field-Programmable Gate Array)
• CUPL
• VHDL
• Verilog
ULA –
Uncommitted Logic
Array
Verilog
Reversible
Counter
mod 16
Logical structure
of PLD
/romwr = /WR + A13 + A14 + A15 + rom + /cm
CUPL – boolean equation:
Hardware Description
Languages:
FPGA structure & logic cells
FPGA
Field-Programmable Gate Array
opencores.org
Microcontroller 1986VE91T (ARM Cortex M3), proces 180nm
(manufacturer Milandr, Russia)
made of synthesized cells and blocks…
zeptobars.com/en/read/MDR32F9Q2I-1986VE91T-whats-inside-russian-arm