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I am using callbackOnCompare in the qt_sState structure for the quad timer. Could somebody explain how the callbackoncompare works, and also what InitialLoadValue does in relation to the following structure. const qt_sState XXXXXX = { /* Mode = */ qtCountBothEdges, /* InputSource = */ qtPrescalerDiv128, /* InputPolarity = */ qtNormal, /* SecondaryInputSource = */ 0, /* CountFrequency = */ qtRepeatedly, /* CountLength = */ qtPastCompare, /* CountDirection = */ qtDown, /* OutputMode = */ qtAssertWhileActive, /* OutputPolarity = */ qtNormal, /* OutputDisabled = */ 1, /* Master = */ 0, /* OutputOnMaster = */ 0, /* CoChannelInitialize = */ 0, /* AssertWhenForced = */ 0, /* CaptureMode = */ qtDisabled, /* CompareValue1 = */ 0, /* CompareValue2 = */ 0, /* InitialLoadValue = */ /* CallbackOnCompare = */ { qtimer_CallbackOnCompare, 0 }, /* CallbackOnOverflow = */ { 0, 0 }, /* CallbackOnInputEdge = */ { 0, 0 } }; |
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qt_sState structure
Started by ●August 5, 2003
Reply by ●August 6, 20032003-08-06
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Hi CJ, The CallbackOnCompare is an interrupt that occurs when the CompareValue2 is reached when counting down (in the structure sample you have below). The InitialLoadValue is the value loaded when the timer is initialized either by a compare or by a different "Master" timer. In your sample structure the timer will never initialize because the CountLength is set to qtPastCompare so the counter will keep counting 0, 0xFFFF, 0xFFFE, ... 2, 1, 0, 0xFFFF, ... With the CallbackOnCompare set up you will get the interrupt each time the counter reaches 0 and will execute your qtimer_CallbackOnCompare interrupt service routine. Hope this helps, Pete --- In , "TA1T" <cj_tait@h...> wrote: > > I am using callbackOnCompare in the qt_sState structure for the quad > timer. Could somebody explain how the callbackoncompare works, and > also what InitialLoadValue does in relation to the following > structure. > > const qt_sState XXXXXX = { > > /* Mode = */ qtCountBothEdges, > /* InputSource = */ qtPrescalerDiv128, > /* InputPolarity = */ qtNormal, > /* SecondaryInputSource = */ 0, > > /* CountFrequency = */ qtRepeatedly, > /* CountLength = */ qtPastCompare, > /* CountDirection = */ qtDown, > > /* OutputMode = */ qtAssertWhileActive, > /* OutputPolarity = */ qtNormal, > /* OutputDisabled = */ 1, > > /* Master = */ 0, > /* OutputOnMaster = */ 0, > /* CoChannelInitialize = */ 0, > /* AssertWhenForced = */ 0, > > /* CaptureMode = */ qtDisabled, > > /* CompareValue1 = */ 0, > /* CompareValue2 = */ 0, > /* InitialLoadValue = */ > > /* CallbackOnCompare = */ { qtimer_CallbackOnCompare, 0 }, > /* CallbackOnOverflow = */ { 0, 0 }, > /* CallbackOnInputEdge = */ { 0, 0 } > }; |
