DW EditSeite anzeigenÄltere VersionenLinks hierherAlles aus-/einklappenNach oben Diese Seite ist nicht editierbar. Sie können den Quelltext sehen, jedoch nicht verändern. Kontaktieren Sie den Administrator, wenn Sie glauben, dass hier ein Fehler vorliegt. CKG Editor ====== 5. Storage Elements ====== In the previous chapter we have had a look onto memory devices, which store data even when no voltage is applied. This is great for longterm storage, like measurement data, pictures or music. The clock frequency of the storage element are often much lower than the internal frequency of the processor / controller. By this, the processor has to wait for the stored information due to high access time. Therefore an controller-internal memory is advantageous. These are often called cache. Distinct storage elements have special properties, e.g. the written data changes the logic level of a pin ('foot') of the IC directly. We will now focus onto these controller-internal, fast memory, which consist of logic gates. The name flipflop stemms from the fact, that the smallest logic circuit for storing data has to store binary values. Therefore, it has to show one of two stable states, and can flip into the other one by an external interaction. ===== 5.1 Flipflop as a Blackbox ===== In order to understand the wanted storage element, we will first look onto these element based on the IPO model (input–process–output). The process of the storage element is to store two different states. This property can be implemented via two inverting gates which are interconnected in a feedback loop. The simple setup would be with NOT gates as shown in <imgref pic01>. <WRAP><well> <imgcaption pic01|Storing two different states></imgcaption> \\ {{url>https://www.falstad.com/circuit/circuitjs.html?hideSidebar=true&ctz=CQAgjCAMB0mQrFWAmeyAcBmAnPX7IAWAdkIDZF5IRFDMaBTAWjDACgBJcMZcM6sMTJ9qo6JU7ghIZIQE8ZcqEkRhIbAO5ThYftsWjN3XrPm9dhrcmIml183vVbMmHXpfDTUSR4MybfmISXPYiIL4WyjCq6lysvJho+om8QTSS8SCEuvrZwmlqRpkpxuFk6N5agsJ5uXCVdWZlFU7JSdXNDR2uFZlylqX9gzmtoUNjI0a+Pf68Q63TSdPlDb7jATMLrlk5a-WjG0mhm5ITwmsjKukhhwnbJQXqAEYg6NjgyO-IalnwEM8yHDgTAQVzUQjwejqAAe3EQmCI4HQhHCkGIWUUIAANgB7ADmAEsAMYAHQAzjCZGR0Qi7ucEBjZNj8cTyewgA noborder}} </well></WRAP> Of course this simple elements misses inputs and outputs! Therefore we have to look into these now. The input of this element needs at least two inputs. Often the following two are used: * Set input: once this input is high, a $1$ is stored. This input is marked as $S$. * Reset input: once this input is low, a $0$ is stored. This input is marked as $R$. For the output also often two pins are shown. The pin $Q$ outputs the stored data directly. The pin $/Q$ outputs the inverted value. Based on this simple requirements we can create the truth table. * When $S=0$ and $R=0$, nothing changes and the outputs stay the same: $Q(n+1)=Q(n)$, $/Q(n+1)=/Q(n)$ * When $S=1$ and $R=0$, the stored information will be set: $Q(n+1)=1$, $/Q(n+1)=0$ * When $S=0$ and $R=1$, the stored information will be reset: $Q(n+1)=0$, $/Q(n+1)=1$ * When $S=1$ and $R=1$, it is unclear what to do. <WRAP> <imgcaption pic02| truth table for flipflop> </imgcaption> {{drawio>TTflipflop}} </WRAP> In <imgref pic02> the last input ($S=1$, $R=1$) reaches a not defined state. This state have to be investigated more later. ====== Examples ====== <WRAP><well> <imgcaption pic100|Shift Register with synchronous Load ></imgcaption> \\ {{url>http://www.falstad.com/circuit/circuitjs.html?hideSidebar=true&ctz=CQAgzCCMCmC0AcIAMA6ArAJgJwBYdaSTSRwHZCJiQ0QdK5JIAoAGVqUQx0Rw5A3hJ+UEADMAhgBsAztGrJWtXv25KhA9cjFTZ8pIuI4ViQ-0HChEmXJr62ZDMdqlHG4ZG3W9igGyEnfurmjh5Wura+YK6qPlFmmpY6NgpsaD6cqmmcwSJhyXbUYD5OaEXx7p7hCgCy7CbFvIiQxa7oTLV4QmlqUC38bbWm3abNwhgDzo7dDr1jE4HUxQujrWjtILFTS3Er-WuD6YuLTX3j+4XFw2W7Z0wASuCkxZAYQmB4UK8iIYS-6uh7LSoNZsMBPKCYcCQyCQxyJLwRUHgyDwIxgaGoiyVfJMFAgeAAIQAlgAXADKAAsiaISXdoABzInSEnQABOAHVSRSWAB7cQAEy0JigWBAAGEWABpWjfEC8gX4sYgMlEgB2G3AwgAGl1HKQRFqPGh9c8QFrHGBhR4tRA6DLrUYBJrrTQMBAQmbnjQPNb9aKhB4AJpCHDFfVCQMeMgaiMWqZaQMQMC2hNot4J72iuEgQPPH0J-XZoQAEQAYpIiQAHcs8ysAUUkAFsADrSSCtjCtsCtnDN1kAQVV-IA4uIWQ2W9I0K2fK3SH3ByOx9AJ634K2sK3IEg+wB5Vmj8dNrc76Tztt9gCSqoAbmyWazV9J11O9wfl0-IN2272252B0Oh4rsez5btObbdgBS5HpOzQdluvasmWFbVpItafp2bbtm256IchVY1vWIEolum7SK8PYLoBH4gRg2GMB2-6LkBT4vm6HaIfuLG0b+GCYSRrJcTRk4YLO5Hnhg05Qdxk5sWxs7ScJHZkZAZEYPOSHlgRaFESJ4FgKeYDYXhWmoehIHvF2mHopRikwV2YnJl2GnMUpoHSJaXaboJ772R5ZFgl2nG+cBk44MZmG8FR0GhWuPbfuF0UyT2v4GT2-74WZuk9oZCXgSZKGEU+3A9mJ+C2a5fnED255oO2dmxe5mCtqUb7JVO351T264+e1aDgWkLWIZVjUvsaLVSSNT5oC+UQtQpmVFSBaC-mQLVkYhvKMgAxruACuJKVgdT7eVtRK7QdR0kp+UlnRdh3HbRPV3ftD3XbRkEvZdj2TuNrJfW903-gDV1Pp5-08jtr2gyBdB9iDP1dp9kPndDiMecDKP3TDYUKQj71hRp+OfqdWNowTXY7hDUPfRTWHw2TtNPv+153qyD6sVuCms-ebKc+R9U8+zfMgS+eBXrevOPqLykS2zHMy1OPVCwrskOXLUv81Q7atqeOvkc2uuG6+F7wUbLVbsbnbmybO66+gxvgfr1vSHbJvO8bbtO1bnuO5bRum67-sGzb3tm0HFuBy7XvB9HftR77kce6Hwd677CcpxnEfuz7mfJ9nYchwXseJznAf62n4cx1n1f57XufFzX8d1836cu2c4cd0XXftw73d9734GD53A9W6PHbj+Rk892PQ+zyPc8T+BbvAvHK8O5H6-Tpvnsb7bu-b-v9uH8vB+O0w4VvOC8CIJaRiMB6hKkpS1K0gyTIPpyJLcnygrYQG8Eg5TigIA083pQEtWQMfSB2FMJgJAQbIB4DEHwP-gggBKCYEQOAbAgOyC4FYMwTg7ByCMEYIIcQoh+C8EIIodQpBtCaFoOYSQxhDDcHsNYRw1BXDdb8CXvwqeroBGYTOIIsRoiASSOEUI8RUiREKNkdIuRMiJECNPKvYBGi+62GgVovRujXY6KgUYgaJjNFrCAA noborder}} </well></WRAP> <WRAP><well> <imgcaption pic101|Shift Register with synchronous Load, Direction Bit and Sout></imgcaption> \\ {{url>http://www.falstad.com/circuit/circuitjs.html?hideSidebar=true&ctz=CQAgzCCMCmC0AcIAMA6SAmMkBsnsBZN8B2JfATmJAFYkaR8Jq5JIAoAGQaUXXjvw9wGEOiggAZgEMANgGdo9JJwaDR-VXSxixdafMXVkK2vnV1TwnckmyFSlSR0anV0eP32jyrtiR0+Oj8tETFIWwMHXzBnIJi3XQivYy5qbF4NNMRtd3DPQxSaMGxzIpKcsKSC5QBZbkQ0+qgSnRRqNjr8NUauuhx3dDaOmjIaEst+1vbO4jEe2eaBobrgsZBVydFl9fjG7HjNwemxhvH0xanh6mK165LDoYAlcGJ79C0uqHfxMP8--y2RiONlQ7S4YFeUGoYjA0Kh1jydmqbBQIHgACEAJYAFwAygALTESbGPaAAc0xcmx0AATgB1DgAeykABMACKYmk2RAtcIAYQ4AGkGD8QGyAJLPcjgdwcADyAEE2fRrLjxQA5EBUMxiXFygCqABUXiKIAAND5a8Rm8JgILWnTja0QdBiMzhM3u7LWoybD33PrWqglQMATRCVroofC6GDNlDOiY8YgkGlZij7qoECjvpj8ZKiHCUaoiTobIAYjJMQAHSuM6sAURkAFsADpySDt9DtsDt-CtmlMikAYzlAFdsdWJ0223JsAOh5jRxOp9iZ12BzUxzJsTWZNAAB609dyYjt+dyeDn9vUdvkdudmlbnd7w-HlsbjtIB+dr83u8Pt2g6MiO46TtOH6XguIFLmBq4npA340hWVa1jI9YId2UEdr2cj9shlY1nWjaQZA-Ydr+kC3nh0GgSuEGzjgtGwfRa6kY+z67tW+5HjSJ5Xh2F6QGegn-nI94dvhnGvrxCGUQJqYPgJ1ESe8zHLuBbGMWewF0ZpCFXgRqHESeakdiJ6C-lJ25cTx77aV2WGYI5Ymqfhi4afBpH3rpLH6ZBroDihRHoSRs7oORilyOg1HWS+3Fvnx3ldhesYpa5XaGR5cEMV2va+Z5uXRfORkhRhAUCc50USXFtmJaZuF2j2v5NXIKk9kB2WsaZOldf5s5NaVaHlQNTkiWAuG1TJ9lduN5FzRlciwupOVac1K3dZBYD4cFw1hT21FYD2F5TQlslbS15FYRe7VLb1MGFWtS3uq27bftFr3RW0G5dt9HafVhnaft2v3USDX3UUDcjvVD73g0cP0Qw+API8DAN-fDf2w6jH0faDiMI-9b04056Ng2TOMwyjeNIzThPY0TuOY+T+OM1TaOg2w+CIS8BaIF0hY3OEGI4gSRIkuSlLUvSTKshyXK-kCoOiMrv5hF2KsQ5rwK-n0N7a20Bu+hratG2butQBrTmG9bxttZb0Vm7bDt2zoyvO4rDtu1rHtvV7RsqBC9zwGYsJhCH7h6EiDgrAQoj9OkvAPGCvPx+UcKWS0Nj5A4QA noborder}} </well></WRAP> ====== further Links ====== * https://www.electronics-tutorials.ws/sequential/seq_1.html * https://www.electronics-tutorials.ws/counter/count_1.html