| ??? 09/05/04 13:44 Read: times |
#76912 - RE: debouncing for matrix keypad ? Responding to: ???'s previous message |
Prahlad J. Purohit wrote: ------------------------------- If your routine reads the keyboard every 15-30ms than its most likely that your key gets debounced during this period. Hello prahlad exactly! If your routine considers a valid pressing only if found pressed in two consequetive routine calls then what exactly are you doing is software debouncing. Whats so special about it? no no! what I'm trying to stress is: there is no need for the routine to consider a valid pressing only if found pressed in two consecutive routine calls. why ? I say it again there are 2 situations 1- when key is pressed the routine reads correctly a low state at the first reading. then everything is ok because routine correctly reports a key at the first call and in consecutive calls as you said there is abosolutely no worry because it has been debounced anyway. 2- when key is pressed the routine reads falsely a high state at the first reading. then again everything is ok because routine does not report any key at the first call but in the next call it has been debounced anyway and the routine reports a pressed key. thank you |
