+dhe Posted February 2, 2020 Share Posted February 2, 2020 While source parts for Stewart Connors 99000 board, there is a call for a TMS9902. I vaguely remember, and hoping someone could help, that you could always replace a 9902 with a 9903, but not vice versa? Thanks for any help. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted February 2, 2020 Share Posted February 2, 2020 The biggest difference is that the 9903 is a synchronous chip. . . Quote Link to comment Share on other sites More sharing options...
Stuart Posted February 2, 2020 Share Posted February 2, 2020 2 hours ago, Ksarul said: The biggest difference is that the 9903 is a synchronous chip. . . Indeed, which means that you'd have to sit at your terminal typing away at a steady speed, never slowing down or deviating, never stopping ... I suspect what dhe vaguely remembers is that you could pop a 9903 in a 9902 socket (it is one pin shorter so has to go at one end of the socket), but the synchronous protocol and serial connections are different to the RS-232 interface provided by the 9902. You *can* design the board to support both but it needs a 25-pin serial connector and you need a terminal that supports the same synchronous connection. Quote Link to comment Share on other sites More sharing options...
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