David Wilson wrote:
Michael J. Mahon wrote:My mistake--the copyright date on the card appears to be 1978 (1976??), and the earliest preliminary 6551 datasheet I can find is 12/80!The 6551 was not the first ACIA or UART to be released. Intel had the 8251A (preliminary data sheet dated 1978) and Motorola had the 6850.So apparently, UARTs weren't available when this board was designed!This may be true.
Thanks for the additional dates. I expected it to be easy to Google for the UART chip introduction dates, but it was much less productive than I hoped. Even the "histories" of the companies didn't make the introduction dates very clear, except for "major" things, like microprocessors. I half expected that there would be a chip indroduction database on the web somewhere. ;-) -michael Music synthesis for 8-bit Apple II's! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it is seriously underused."