On 04/13/2012 10:57 PM, Pasi 'Albert' Ojala wrote: > On 04/13/12 20:59, Gerrit Heitsch wrote: >> So unless the circuit that converts the 9V AC into a 50 Hz TTL-signal >> contains some kind of filter, the TOD clocks cannot be accurate. > > Hi, > > There is nothing impossible about using a filter at the TOD input pin, > and it can have input hysteresis to guard for noise. When I built my own 50Hz circuit for an Amiga 2000 power supply years ago I just ran a few gates of a 74LS14 in series after the opto coupler and then used a 10nF cap between one of their output/input connections and ground. Not recommended to do it this way, but it worked flawlessly for years and improved the accuracy greatly. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2012-04-14 17:00:22
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