xerox 19790726 Change to IOP Module free download

File name 19790726_Change_to_IOP_Module.pdf

Laurel Message From: SPG Date: 26 JUL 1979 0903-PDT Subject: Change to lOP Module To: Fairbairn XEROX \Ve have incQrporated the following change into the lOP ~Iodule as a result of investigation into Keyboard-Mouse sampling. The problem uncovered was that the 8748 in the Keyboard was expecting the Tl input(Start Transmission') to stay low until the 8748 could respond to the request to send data. Since this signal was driven by the UART on the lOP, it would normally only be active for one bit time (the Start bit) of a character containing zeroes. This would only be about 16 microseconds every 33milliseconds. The 8748 only looks -:.t t-hn -linn -:>h.1"\11t nnl"o nun-rtl 'lJ\{) TYlir-rnenr-Anrte en TYI~n" r&>1"111&>('tc to """ U.I.'- J.J..I.J."" UVV"",... V..\.J...,..., ,.., l' ".I. J JVV .1..1..1.1.,,'" V"''''''''',-,.I..I.'-6-U r...J'''' .