SN54/74LS90, SN54/74LS92, SN54/74LS93 Decade Counter; Divide-By-Twelve Counter; 4-Bit Binary Counter

used products:

1. Arduino UNO
2. SN74LS90N

Arduino:

void setup() { pinMode(13, OUTPUT); } void loop() { digitalWrite(13, HIGH); digitalWrite(13, LOW); delay(500); }