 |
 |
|
 |
 |
ZBasic System Library
109
ZX Microcontroller Family
GetElapsedMicroTime
Type
Function returning UnsignedLong
Invocation
GetElapsedMicroTime(timeBuf)
GetElapsedMicroTime(timeBuf, timeBuf2)
Parameter
Method
Type
Description
timeBuf
ByRef
array of Byte
The earlier time data.
timeBuf2
ByRef
array of Byte
The later time data.
Discussion
This function is useful for implementing higher precision timing than can be obtained using
Register.RTCTick. It calculates the elapsed time between an earlier instant in time (as captured by
GetMicroTime()) and a later instant in time. If the second parameter is not provided, the later instant is
represented by the RTC time data at the time of the call.
The return value has units of the period of the frequency at which the TCNT register of the RTC timer
changes, typically 1/230.4KHz or about 4.34uS. The value of Register.RTCTimerFrequency
(typically 230.4KHz) may be useful for converting the return value to seconds.
The array is expected to contain at least 5 bytes, populated by a previous call to GetMicroTime(). The
return value will range from 0 to the equivalent of about 15,000 seconds. A return value of &HFFFFFFFF
indicates that an overflow has occurred, i.e. an elapsed time that is too large to represent.
Although this function does not take into account the value of the “day” counter of the RTC, it does
properly handle an elapsed time that spans one midnight rollover.
Example
Dim t0(1 to 5) as Byte
Call GetMicroTime(t0)
<other code>
Dim delta as UnsignedLong
delta = GetElapsedMicroTime(t0)
Compatibility
This function is not available on ZX models that are based on the ATmega32 processor (e.g. the ZX-24).
Moreover, it is not available in BasicX compatibility mode.
See Also
|
 |
|