ZBasic System Library
229
ZBasic Microcontrollers
Type
Function returning Byte
Invocation
PortBit(portIdx, bitIdx)
PortBit(pin)
Parameter
Method
Type
Description
portIdx
ByVal
integral
The I/O port designator (A=0, B=1, etc.)
bitIdx
ByVal
integral
The bit designator (0-7)
pin
ByVal
integral
A pin number
Discussion
This function returns a composite value that describes a specific bit in a specific I/O port. The fields of the
Byte value are as shown in the table below.
Bit(s)
Description
7
Always 1
6-3
The I/O port designator (A=0, B=1, etc.)
2-0
The bit designator (0-7)
When invoked in the first form with the parameter values 2 and 6 (representing Port C, bit 6) the return
value will have the bit pattern &B10010110.
The second form of invocation converts a physical pin number to the composite value representing the
port and bit corresponding to that pin. When passed an invalid pin, the return value is zero.
Values returned by the PortBit() function may be used anywhere that a pin number may be used, e.g. as
the first parameter to PutPin(). The primary advantage to using the composite port/bit designator is that
the same value may be used unchanged on any ZBasic device having the referenced pin.
Note that the special port/bit designators like C.2 are converted by the compiler to the same type of
composite port/bit designator described here if the compiler directive Option PortPinEncoding On is
specified.
Compatibility
This function is not available in BasicX compatibility mode.
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