Electronic Engineering Terms

Dictionary of Electronic Terms
"A" "B" "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
"N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"

Up/Down Decade Counter IC

High Speed Logic Presettable Synchronous BCD Decade Up/Down Counter with Asynchronous Reset

54F192 4-Bit Up/Down Decade Counter Circuit

Up/Down Decade Counter.
The 74192 is a Presettable Synchronous 4-Bit Up/Down Decade Counter.
Presetting the counter to the number on the preset data inputs (Input A - Input D) is accomplished by a LOW asynchronous parallel load input (Load). The counter is incremented on the low-to-high transition of the UP input (and a high level on the Clock- DOWN) and decremented on the low to high transition of the DOWN input (and a high level on the UP input). A high level on the CLR input overrides any other input to clear the counter to its zero state. The Terminal Count up (CO) goes low half a clock period before the zero count is reached and returns to a high level at the zero count.
The Terminal Count Down (BO) in the count down mode likewise goes low half a clock period before the maximum count (9 in the 74192) and returns to high at the maximum count. Cascading is effected by connecting the CO [carry] and BO [borrow] outputs of a less significant counter to the Clock-Up [UP] and Clock-Down [DOWN] inputs, respectively, of the next most significant counter.

A Counter would be considered standard logic or glue logic when a discrete IC is used. However, it would also be considered an MSI Function [Medium Scale Integration]. Also refer to a Counter in VHDL.

Count Sequence

BCD Count Sequence A decade counter counts in BCD, from zero to 9 when up-counting and from 9 to 0 when down-counting. There are no other counts, once 9 is reached the count is recycled and begins at zero again. However counters may be cascaded so that as one counter reaches terminal count, the next one in the chain begins counting.

4-bit Counters by Function:
Note in most cases when a 74xx device is listed, but a 54xx device may also available.
74xx represents the commercial temperature range and 54xx represents the industrial [military] temperature range [IC Prefixes].

74160 4-bit Decade Counter [Asynchronous reset]
74162 4-bit Decade Counter [Synchronous reset]
74190 4-bit Up / Down Decade Counter [Mode control]
74192 4-bit Up / Down Decade Counter [Asynchronous reset]

Standard TTL part numbers are shown but it's more likely that a newer logic family would still be in production; 54AC190, 54ACT191, 54HC192 and so on.

Part number Decode [SN74F192A]
SN; designated Texas Instruments [Company prefix Prefixes]
74; commercial temperature range [IC temp Ranges]
F; Fast [Logic Families]
192; logic function [4-bit Decade Counter]
A; Ceramic DIP (CERDIP package) [CERDIP IC Package]