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Re: Question of Timer interrupter !!
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新會員
 
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我跑模擬都是4秒耶!!並不是1秒
我計算的方法是 [1].(8*7.3728Mhz/4.0)=14.7456Mhz [2].instruction cycle=1/14.7456mhz=0.067817us [3].if timeInS=1;period算出來是=>(14.7456Mhz/256)-1=57599 [4].57599*0.067817=近似於4 sec 這樣算對嗎?? help me please !! 
發表於: 2005/5/24 13:38
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Question of Timer interrupter !!
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新會員
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#define PLL_VALUE 8.0
#define CLOCK_TICKS 7372800 #define TCY_PER_SECOND (PLL_VALUE*CLOCK_TICKS/4.0) #define PRE_SCALE 256.0 void setupTimer1(float timeInS) { unsigned long period; period=(unsigned long)(timeInS*TCY_PER_SECOND/PRE_SCALE)-1; ConfigIntTimer1(T1_INT_PRIOR_3 & T1_INT_ON); OpenTimer1(T1_ON & T1_GATE_OFF & T1_IDLE_STOP & T1_PS_1_256 & T1_SYNC_EXT_OFF & T1_SOURCE_INT,period); } //---------------------------------------------------------------------- (1)這是間隔1秒的 sample code 其中我了解TCY_PER_SECOND是怎麼計算出來的,但是不了解為何要除PRE_SCALE;而且未啥要除以256才會產生間隔一秒的中斷?? (2)在使用ICD2做模擬時;我使用Stopwatch的功能觀看中斷的時間時;發現跳入中斷的時間跟設定的不同(並非1sec中斷);已知我在Processor Frequency設定為14.7456mhz;不知道原因再哪?? (3) 中斷服務程式 void _ISR _T1Interrupt(void){} 與 void_attribute_((__interrupt__)) _T1Interrupt(void) 好像是通用的;若是未闔c30 user's guide都沒提到??
發表於: 2005/5/24 11:45
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