Use of Port B for Data bus while using INT1 pin from Port C

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    Question: I want to use the INT1 pin as a strobe (for example when the converter samples, it sends the strobe to the core and it reads the byte and sends it), but the INT1 pin is on PORT C, so I can't use all 8 port C pins as I/O pins. Which pins should I use to get the byte of data? Can I use the 8 8051 data bus pins and how?



    That is correct, you'll have to sacrifice the INT1 alternate function if you want to use all 8 lines on port C. The data bus for this package can only be used in conjunction with the fast transfer feature to move data. The strobes coming from the 2135 would then be FWR# and FRD# (alternate functions of PA4/PA5). The 2131 has the Port B you're looking for.