I don't know anything about this clock in particular but I have come across several other designs where a mix of TTL ic's, CMOS ic's and other ic's with different VCC capabilities has been used, some starting to operate from as low as 1.8V and some like TTL above 4.75V, but all capable of running at 5V as the main VCC voltage.
The problem with these designs have all been that the microprocessor has started at the lowest voltage of all ic's which has then led to latchups in some of the external ic's as they weren't ready to work until the voltage had risen above their minimum operating voltages. The microprocessor started to run its program and communicated with them right away when it was ready as it used its internal power on reset and thought that everything was green to go. Now some of these designs worked for years until they failed due to different reasons, possibly ageing components, some only worked for a short while and some were problematic intermittently. All of these problems were due to not waiting for the voltage to rise above the minimum voltage for the type of ic used with the highest minimum voltage requirement - this I feel can only be blamed on bad design, or poor knowledge on how things should be designed. In some cases there has been differences between different manufacturers producing the same ic, one under license from the other, and even within different runs from the same 2nd source manufacturer. Even if different manufacturers produced the same ic they didn't work equally under the startup conditions when voltages where rising to their operating levels (and in some cases when the voltages were being removed), in some cases it resulted in lockups or strange behaviours later when the ic in question was being used. Fortunately most of the problems I have come across could be remedied by adding a POR (Power On Reset) ic to the microprocessor halting it until power had risen to the required level for the TTL ic's that were the most problematic. Trying to locate this kind of problem is very time consuming but when you know about it is one of the first things I check in a mixed ic environment. /Martin -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/e71d1a6a-8f96-4cb6-99ea-6a06eff58a00%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
