Red light numerical control circuit

Red light numerical control circuit
The design uses a 74LS283 full adder, which adds A0A1A2A3 and B0B1B2B3, and the sum is output by S0S1S2S3, and C1 is the carry output. This circuit realizes the function that the sum of the time when the green light and the yellow light in the east-west direction are equal to the time when the red light in the north-south direction is on. That is, after the green light in the east-west direction is on for 9s, it turns into a yellow light for 3s, and at the same time, the red light in the north-south direction is on for 12s, so that the red light display data is synchronized with the yellow light.
Considering the design needs, this system uses 3 74LS283 full adders, 74LS32 and 74LS08 chips. This module The circuit also realizes the conversion between binary and BCD codes, so that when the display value is greater than 9, the hexadecimal is converted to BCD code. In addition, when the adder is used to calculate the red light display value, a 1-bit hexadecimal to 2-bit BCD code conversion is performed. The circuit is shown in Figure 6.

Figure 6 Schematic diagram of the red light numerical control circuit