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4510 Counter

Introduction

pinoutThe 4510 is a counter. The full name of the counter is a Divide by 10 BCD Up-Down Counter. The divide by 10 part means it counts 10 (0 to 9) clock pulses before starting again. The BCD part stands for Binary Coded Decimal and the Up-Down part means the counter can either count up from zero or down from 9.


Basic Operation

There are four outputs Q1, Q2, Q4 and Q8. The output is in binary where Q1 = 1, Q2 = 2, Q4 = 4 and Q8 = 8. In the most simple application, Carry In (CI), Reset (RST) and LOAD are held LOW by connecting them to 0 V. The binary number represented by the four outputs increases or decreases by one on each rising edge of the clock (Ck) pulse. The value of the Up-Down (U/D) input determines whether the count increases or decreases.

The 4510 is a divide by 10 counter. The outputs count from Zero to Nine and then start again at Zero.

Making Reset HIGH will make all the outputs LOW resetting the output to binary zero.

A binary number can be loaded in to the counter using the load lines L1, L2, L4 and L8. L1 to L8 are connected either HIGH or LOW depending on the binary number required and then the LOAD input is made HIGH momentarily. The value on the load lines is transferred to the outputs. This is useful to make a counter that counts from ONE rather than from ZERO for instance.

Two counters may be connected together (cascaded) by connecting the Carry Out (CO) of the first counter to the Carry In (CI) of the second counter and connecting both counters to the same clock. Carry In of the first counter should still be connected LOW.

Carry IN (CI) can be used as a clock enable. When Carry In is held HIGH, the clock is ignored. When Carry In is held LOW, clock pulse are counted.

The Up-Down input (U/D) determines whether the count increases or decreases with each clock pulse. The counter counts Up when U/D is HIGH and the counter counts Down when U/D is LOW.


Basic Circuit

4510The most basic configuration:

LOAD and CI are held LOW

U/D is held HIGH

RESET is held LOW by a pull down resistor. Pushing the Reset button makes RESET HIGH and returns all the outputs to zero.


Example Circuits

Example 1: Count from 0 to 6 and then start again

Example 1CLOCK receives the pulses to be counted

CI and LOAD are held LOW

U/D is held HIGH

The AND gate goes HIGH when Q1 = 1, Q2 = 1 and Q4 = 1 which corresponds to decimal 7. The output of the AND gate is connected to RESET and so the counter is immediately reset to zero when it reaches a count of seven. The counter counts from 0 to 6, on the 7th count it is reset to 0.


Example 2: Count from 1 to 6 and then start again

Example 2Sometimes it is more useful to start counting from 1 rather than 0, when making a dice for example

CLOCK receives the pulses to be counted

CI and RESET are held LOW

U/D is held HIGH

L1 is held HIGH and L2, L4 and L8 are held LOW. The four load inputs are held at the binary number 0 0 0 1 which is equivalent to decimal 1

The AND gate goes HIGH when Q1 = 1, Q2 = 1 and Q4 = 1 which corresponds to decimal 7. The output of the AND gate is connected to LOAD and so the counter is immediately loaded with the values at the load inputs, in this case 1. The counter counts from 1 to 6, on the 7th count it reloads the value 1 to the output


Example 3: Count from 6 to 1 and then start again

Example 1This is very much like example 2 but, as well as making the counter count down, the logic also needs to be changed. When the output is equivalent to decimal 0, the output must be reloaded with decimal 6

CLOCK receives the pulses to be counted

CI and RESET are held LOW

U/D is held LOW so that the counter counts down

L1 and L8 are held LOW, L2 and L4 are held HIGH. The four load inputs are held at the binary number 0 1 1 0 which is equivalent to decimal 6

The NOR gate goes HIGH when Q1 = 0, Q2 = 0 and Q4 = 0 which corresponds to decimal 0. The output of the NOR gate is connected to LOAD and so the counter is immediately loaded with the value decimal 6 on the outputs. The counter counts from 6 to 1, on the 7th count it reloads the value 6 to the output