From: utzoo!decvax!harpo!npoiv!npois!houxm!houxa!houxi!houxy!houxw!rbc Newsgroups: net.micro Title: Which Parallel I/O Chip? Article-I.D.: houxw.119 Posted: Tue Jan 11 08:56:39 1983 Received: Fri Jan 14 03:15:34 1983 I am currently designing a micro processor board. The problem is which parallel I/O chip will I use. Currently the options are INTEL 8255A 3 8-bits ports or Synertek 6520A 2 8-bit ports with handshake signals I have used both parts and am partial to the 6520A. I have heard a few negative things about the 8255A: - Single Bit I/O operations on ports A + B do not always work. - That writting the control register causes glitches on the outputs. (very bad) Has anyone else heard this? Any other gotchas? Are there any other chips I should consider? Thanks. Robert Connaghan - Bell Labs; Holmdel, N.J. 201-949-5649 (collect is OK) houxw!rbc