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Importance of 9-valued logic
editThe IEEE1164 defines the terms, that are in wide practical use in digital circuit design. Logic zero and logic one is not sufficient for connecting data buses or for circuit simulation. IEEE1164 library is heavily used in VHDL code.--95.173.68.226 (talk) 10:38, 5 January 2022 (UTC)
Strong and weak
editWhat is the difference between strong and weak drive? Thanks, --Abdull (talk) 23:20, 7 February 2010 (UTC)
- Strong drive means, that the signal is connected via low imedance either to a logic one (Vcc, +5V in TTL logic) or to a logic zero (0V). Weak drive means, that the signal is connected via a significant impedance (typically more than 1 kOhm) either to a logic one or to a logic zero. If a weak and strong logic signals are connected, than the strong signal prevails. In case of connecting strong one and strong zero a short circuit occures and the device is damaged.
- Combination of strong and weak signals is typically used with bus logic, such as i2c. The i2c signals (data and clock] are permanently connected to a weak one. The device that communicates uses high impedance 'Z' for logic one and strong zero '0' for logic zero. This ensures, that a short circuit does not happen.--95.173.68.226 (talk) 10:38, 5 January 2022 (UTC)