On September 17, 1971 (two months before the 4004), the Texas Instruments TMS0100 (originally designated TMS1802NC) was announced as a "calculator on a chip" that integrated a CPU with ram and a program read-only memory. But while it was marketed as "totally programmable", this programming had to be done by changing a photomask in the manufacturing process. It along with its 1974 successor the TMS1000 (which used a factory-programmed mask ROM) have been considered the first microcontrollers — a computer on a chip containing not only the CPU, but also ROM, RAM, and I/O functions and which typically contains a permanent on-chip program that directs the chip to perform a dedicated function. While its designer was recognized by the US Patent Office in 1996 as the inventor of the microcontroller, microcontrollers generally run a fixed internal program and aren't easily reprogrammable and so are distinguished from microprocessors. But because the 4004 executed instructions from external memory, it can serve in a general-purpose computer that is easily programmed and so is distinguished as a microprocessor.
on septembeR 17, 1971 (twO moNthS BEfOre The 4004), thE texaS iNstrUmentS TMS0100 (orIGinaLly deSignaTed tmS1802NC) wAS annOunCEd AS a "cAlCulatoR On a Chip" thaT iNtegrATed a cpu with rAm ANd a prOGram reaD-oNly meMory. but WhILe it was MARKeted aS "TotallY ProgrAMmAble", tHIS pROgrammiNg Had tO be dOne By cHanginG a photoMask IN the maNUfactUrIng proCEss. it along wITh its 1974 succEssoR tHE tMs1000 (WhiCh useD a faCtory-PrOgraMmEd mask rom) haVe BeeN ConSiderEd thE fIrst mICrocoNTrOLLErs — a CoMpuTer on A Chip CoNtaINing Not ONLy tHE cpu, buT alsO rom, ram, And I/o FuncTiONS aNd WhiCh TypiCaLly contAiNs a pERmAnENT ON-Chip program THat DIrEctS the chip tO PerfoRm A dEdicAted FunctiOn. WhIle iTs desigNer waS recoGNizED By thE uS PatENt office in 1996 as the inventor oF the MiCROcOnTroller, Microcontrollers GenerallY run A Fixed IntErnaL program and aren't Easily REprOGrAmMabLe aND so aRe diStinguIShEd fROm mIcroProcessORs. But bEcauSE The 4004 exEcUted iNStrUCTiOns fRom extErnAL meMOry, It CAn sErvE In a gENeRAl-pUrpose ComPuter that Is EASIly PRoGramMeD anD sO Is DISTIngUIsheD as a mICroprOCEssor.