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Other Technologies7400-Series Logic ICsUsing Logic ICsSlide 4Slide 5Programmable Nodes in an SPLDPLD Drawings and PLD Implementation ExamplePLD ExtensionsMore on PLDsTechnology ComparisonsSlide 11Key Trend in Implementation Technologies1Other Technologies•Off-the-shelf logic (SSI) IC–Logic IC has a few gates, connected to IC's pins•Known as Small Scale Integration (SSI)–Popular logic IC series: 7400•Originally developed 1960s–Back then, each IC cost $1000 –Today, costs just tens of centsI14 I13 I12 I11 I10 I9 I8I1 I2 I3 I4 I5 I6 I7VCCGNDIC27400-Series Logic ICs3Using Logic ICs•Example: Seat belt warning light using off-the-shelf 7400 ICs–Option 1: Use one 74LS08 IC having 2-input AND gates, and one 74LS04 IC having inverters(a) Desired circuit(c) Connect ICs to create desired circuitI14I13I12I1174LS08IC74LS04ICI10I9I8I14I13I12I11I10I9I8I7I4wkpI1I6I3I2snI5I7I4I1I6I3I2I5kpsw(a)(b) Decompose into 2-input AND gateskpswn(b)(c)aa4Using Logic ICs•Example: Seat belt warning light using off-the-shelf 7400 ICs–Option 2: Use a single 74LS27 IC having 3-input NOR gatesConnecting the pins to create the desired circuit74LS27ICI14I13I12I11I10I9I8I7sk0I3kpsww(a)(c)Converting to 3-input NOR gatesp(b)spkw00I2I4I5I6I1aa5Other Technologies•Simple Programmable Logic Devices (SPLDs)–Developed 1970s (thus, pre-dates FPGAs)–Prefabricated IC with large AND-OR structure–Connections can be "programmed" to create custom circuit•Circuit shown can implement any 3-input function of up to 3 terms–e.g., F = abc + a'c'O1PLDICI3I2I1programmable nodes6Programmable Nodes in an SPLD•Fuse based – "blown" fuse removes connection•Memory based – 1 creates connection1memFuse"unblown" fuse0mem"blown" fuseprogrammable node(a)(b)O1PLDICI3I2I1programmable nodesFuse basedMemory based7PLD Drawings and PLD Implementation Example•Common way of drawing PLD connections:–Uses one wire to represent all inputs of an AND–Uses "x" to represent connection•Crossing wires are not connected unless "x" is present•Example: Seat belt warning light using SPLDkpswBeltWarnTwo ways to generate a 0 termO1PLDICI3I2I1××wired ANDI3I2'×××× ×× ×××× ×wPLDICspkkps'008PLD ExtensionsI3I2I1(a)PLDICO1O2I3I2I1(b)PLDICO2O1FFFFprogrammable bitclkTwo-output PLDPLD with programmable registered outputs9More on PLDs•Originally (1970s) known as Programmable Logic Array – PLA –Had programmable AND and OR arrays•AMD created "Programmable Array Logic" – "PAL" (trademark)–Only AND array was programmable (fuse based) •Lattice Semiconductor Corp. created "Generic Array Logic – "GAL" (trademark)–Memory based•As IC capacities increased, companies put multiple PLD structures on one chip, interconnecting them–Become known as Complex PLDs (CPLD), and older PLDs became known as Simple PLDs (SPLD)•GENERALLY SPEAKING, difference of SPLDs vs. CPLDs vs. FPGAs:–SPLD: tens to hundreds of gates, and usually non-volatile (saves bits without power)–CPLD: thousands of gates, and usually non-volatile–FPGA: tens of thousands of gates and more, and usually volatile (but no reason why couldn't be non-volatile)10Technology ComparisonsFull-customStandard cell (semicustom)Gate array (semicustom)FPGAPLDEasier design More optimizedFaster performanceHigher densityLower powerLarger chip capacityQuicker availabilityLower design costreprogrammable11Technology ComparisonsPLD FPGA GatearrayStandardcellFull-custom(3)(4)(2) (1)Easier designMore optimizedCustomprocessorProgrammableprocessor(1): Custom processor in full-custom ICHighly optimized(2): Custom processor in FPGAParallelized circuit, slower IC technology but programmableIC technologiesProcessor varieties(4): Programmable processor in FPGANot only can processor be programmed, but FPGA can be programmed to implement multiple processors/coprocessors(3): Programmable processor in standard cell ICProgram runs (mostly) sequentially on moderate-costing IC12Key Trend in Implementation Technologies•Transistors per IC doubling every 18 months for past three decades–Known as "Moore's Law"–Tremendous implications – applications infeasible at one time due to outrageous processing requirements become feasible a few years later–Can Moore's Law continue?100,00010,0001,0001001019972000200320062009201220152018Transistors per IC


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UCR EE 120A - Other Technologies

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