Michał Pleban wrote: > It's 2AM now and I am completely of ideas. Does anyone know about what > exacly happens in the 8255 when its Control register is written into? OK, after extensive googling I found this little gem: http://www.cpcwiki.eu/index.php/8255 "CAUTION: Writing to PIO Control Register (with Bit7 set), automatically resets PIO Ports A,B,C to 00h each!" This information (quite important IMHO) is not found in the datasheet. Also, it's a very stupid behaviour for an I/O chip to silently reset the port values when the port direction is modified, but it's Intel, so what did I expect? :-) I just have to modify the IPC code logic somehow to work around this... Regards, Michau.Received on 2018-06-10 03:03:07
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