The vhc161 is a highspeed synchronous modulo16 binary. The counter you will use in lab is the 74xx161, the xx determines what technology was implemented when the chip was built. A counter will increment only when the counter below it is at its terminal count and it is being incremented that isthe definition of the rollover signal some people try to tie rollover to the clk input of the next higher counter bad idea very bad idea violates our globally synchronous policy doesnt work as. The 74161 digital ic comprises of synchronous presettable binary counter with asynchronous clear and utilizes advanced silicongate cmos technology and internal lookahead carry logic for use in high speed counting applications. Because this 4bit synchronous counter counts sequentially on every clock pulse the resulting outputs count upwards from 0 0000 to 15 1111. Dm74ls161a dm74ls163a synchronous 4bit binary counters. General description the 74hc161 is a synchronous presettable binary counter with an internal lookhead carry. They are edgetriggered, synchronously presettable, 74161 synchronous counter dip16,32mhzsigmatechbd,bangladesh. Because presetting is synchronous, a low logic level at the load load input disables the counter and causes the outputs to agree with the setup data after the next clock pulse, regardless of the levels of enp and ent. These synchronous presettable counters feature an inter. Synchronous 4bit binary counter datasheet texas instruments. Ti synchronous 4bit counters,alldatasheet, datasheet, datasheet search site for electronic components and semiconductors, integrated circuits, diodes, triacs, and other semiconductors. The ls160a161a162a163a are highspeed 4bit synchronous count ers.
A,b, and d are all 0 and c is to 1 which is 22 and this equals 4 which is the number that the counter restarts at. This is the 4to14 binary up counter that i had to make by modifying the 29 counter. The active low synchronous reset sr input of the ls162a and ls163a acts as an edgetriggered control input, overriding cet, cep and pe, and resetting the four counter flipflops on the low to high transition of the clock. It achieves the highspeed operation similar to equivalent bipolar schottky ttl while maintaining the cmos low power dissipation. They are edgetriggered, synchronously presettable, and cascadable. To make the maximum count be 14 i put a inverter on q0. Datasheet 74161 pdf these synchronous, presettable counters feature an inter nal carry lookahead for application in highspeed counting designs. Therefore, this type of counter is also known as a 4bit synchronous up counter however, we can easily construct a 4bit synchronous down counter by connecting the and gates to the q output of the flipflops as shown to produce a waveform timing. Function table 74163 presettable synchronous 4 bit counter.
This mode of operation eliminates the output counting spikes that are normally associated with asynchronous rippleclock counters. Jameco will remove tariff surcharges for online orders on instock items learn more. The decade counter is formed by cascading a mod2 counter with a mod5 counter. If preset to state 10, 1 1, within two clock pulses. Texas instruments and its subsidiaries ti reserve the right to make changes to their products or to discontinue. Synchronous 4bit counters, 74161 datasheet, 74161 circuit, 74161 data sheet.
Credit application pdf mailfax order pdf california resale certificate pdf multijuris resale certificate pdf rma request. Counters are used in digital electronics for counting purpose, they can count specific event. Synchronous counter operation synchronous counters have a common clock pulse applied simultaneously to all flipflops. According to wikipedia, in digital logic and computing, a counter is a device which stores and sometimes displays the number of times a particular event or process has occurred, often in relationship to a clock signal. This is similar to an up counter but is should decrease its count. They are synchronously presettable for application in programmable dividers and have two types of count enable inputs plus a terminal count output for versatility in forming synchronous multistage. Dm54161dm74161dm74163 synchronous 4bit counters october 1992 dm54161dm74161dm74163 synchronous 4bit counters general description these synchronous, presettable counters feature an internal carry lookahead for application in highspeed counting designs.
These synchronous, presettable counters feature an inter nal carry lookahead for application in highspeed counting designs. A 2bit synchronous binary counter inputs outputs comments j k clk q q 0 0 q0 q0 no change 0 1 0 1 reset 1 0 1 0 set 1 1 q0 q0 toggle note that both the j and k inputs are connected together. Sn54161, sn 74161 synchronous binary counters are similar. So inputs of jk flip flop are connected to the inverted q q. The ls160a and ls162a can be preset to any state, but will not count beyond 9. Synchronous presettable binary counter general description the vhc161 is an advanced highspeed cmos device fabricated with silicon gate cmos technology. The 4 bit down counter shown in below diagram is designed by using jk flip flop. The gate output is connected to the clear input to synchronously clear the counter to all low outputs. Buy ic 74ls161 4bit synchronous binary counter dip16. The carry lookahead circuitry provides for cascading counters. Production processing does not necessarily include.
The 74ls90 ic counter is an example of a counter circuit that requires cascading in order to obtain a decade counter. The data sheet used is for an mc14161 counter from motorola. That is, it can be preset to any number between 0 and 15. Electronic component search and free download site. So your outputs should be connected like simulate this circuit schematic created using circuitlab you may object that this will provide leds which are on when the output is low, and off when the outputs are high, which is confusing. Synchronous counter and the 4bit synchronous counter. Synchronous operation is provided by having all flipflops clocked simultaneously on the positivegoing edge of the clock cp. It was actually very easy to modify the count once i got the concept of the msi counter. Ti synchronous 4bit counters,alldatasheet, datasheet, datasheet search site for electronic.
Function table 74163 presettable synchronous 4 bit counter with synchronous from ece 2372 at texas tech university. This mode of operation eliminates the output counting spikes normally associated with asynchronous rippleclock counters. I have added a debounce circuit, but still to avail. Down counter counts the numbers in decreasing order. Html pages 1 2 3 4 5 6 7 8 9 10 11 12 14 15 16 17 18 19 20 21 22. Sn5474ls160a sn5474ls161a sn5474ls162a sn5474ls163a state diagram ls160a ls162a ls161a ls163a 12, 14, or 15, it will return to its normal sequence note.
This simplifies the design from racefree logic controlled reset circuits, e. They offer the high noise immunity and low power consumption. Ti, alldatasheet, datasheet, datasheet search site for electronic components and. Counter, presettable binary, synchronous, 120mhz, max count 15, 1.
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