ST10R272L - PARALLEL PORTS
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When the on-chip peripheral associated with a Port 3 pin is configured to use the alternate
input function, it reads the input latch, which represents the state of the pin, via the line
labeled “Alternate Data Input”. Port 3 pins with alternate input functions are:
T2IN, T3IN, T4IN, T3EUD and CAPIN.
When the on-chip peripheral associated with a Port 3 pin is configured to use the alternate
output function, its “Alternate Data Output” line is ANDed with the port output latch line.
When using these alternate functions, the user must set the direction of the port line to
output (DP3.y=1) and must set the port output latch (P3.y=1). Otherwise the pin is in its
high-impedance state (when configured as input) or the pin is stuck at '0' (when the port
output latch is cleared). When the alternate output functions are not used, the “Alternate
Data Output” line is in its inactive state, which is a high level ('1'). Port 3 pins with alternate
output functions are:
T6OUT, T3OUT, TxD0 and CLKOUT.
When the on-chip peripheral associated with a Port 3 pin is configured to use both the
alternate input and output function, the descriptions above apply to the respective current
operating mode. The direction must be set accordingly. Port 3 pin with alternate input/output
functions is: RxD0.
