Observe the . For example, if you press "1", the outputs Q4-Q1 should show 0001 . If you press "9", they should show 1001 . 5. Troubleshooting Common Issues
: Contains the graphical symbol and electrical properties of the chip.
Since the MT8870 is not native, you must import a third-party library. Here is the safe, functional method to add the DTMF decoder.
: Saves time by verifying logic and 4-bit output before building physical prototypes. Imperfect Simulation