hallmont wrote:
6516 should not be controller,because there are two,and the 74ls139 told me that the 6516 is to be "selected",or 'controled'.
True, that would be a good indication.
I did a quick search for just 6516 (without the um prefix), and found HM-6516, which is a 2Kx8 RAM chip. See
http://chipmanuals.com/datasheets/search/go/ for the search engine that Google found for me; this is where I typed "6516" and it came up with a few hits that looks like it might work.
Quote:
6527's pin20 to pin27 are connected to 6538's pin2 to pin9,this seems to be a data link
Not sure if the 6527 is the microcontroller or not, but plugging that into the same search engine as above yields something like this:
LC6527F -- 4-bit single-chip microprocessor for small-scale control-oriented application
It appears to be only 18 pins in size. How big is the 6527 on your circuit?