ZBasic System Library
167
ZBasic Microcontrollers
Type
Subroutine
Invocation
InputCapture(data, count, flags)
InputCapture(data, count, flags, timeout)
Parameter
Method
Type
Description
data
ByRef
array of
UnsignedInteger
The array in which pulse width information will be stored.
count
ByVal
int16
The number of pulse widths to store. This should be no
larger than the number of entries in the passed array.
flags
ByVal
Byte
A value of zero requests that a falling edge begin the
capture process while a value of 1 indicates a rising edge.
All other values are reserved.
timeout
ByVal
Integral
If non-zero, this parameter specifies a timeout value that, if
exceeded, will terminate the input capture process.
Discussion
Invoking this routine is equivalent to the call InputCaptureEx(pin, data, count, flags) or
InputCaptureEx(pin, data, count, flags, timeout) where pin is the default input capture
pin for the device as shown in the table below. See the description of InputCaptureEx() for more detailed
information. Also, see the section Input Capture Timers for information on the default input capture pin
used by this subroutine.
The stored values represent the number of I/O Timer ticks (i.e. 1/F_CPU or about 67.8ns for 14.7MHz
devices) measured for each segment of the pulse train. However, the value of
Register.TimerSpeed1 may be changed to allow longer pulse widths to be measured. See the
section on Timers for more information.
Example
Dim pd(1 to 5) as UnsignedInteger
Call PutPin(12, zxInputTriState)
Call InputCapture(pd, UBound(pd), 1)
Compatibility
The BasicX compiler erroneously allows any variable for the first parameter. This implementation
requires the data type to be UnsignedInteger or Integer although it needn’t be an array. For
practical purposes, an array will almost always be used.
In BasicX compatibility mode, the use of the optional fourth parameter is not supported. Also, because
the processor runs at twice the speed of the BX-24 processor, the default time unit is one half of that
provided for by BasicX.
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