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32 Bit capture accuracy in LPC546xx

Question asked by Prasanna Naik on May 10, 2019
Latest reply on May 13, 2019 by xiangjun.rong


   I am using LPC54608 development board(OM13092) for evaluation of 32 bit capture in Standard counter/Timer module of LPC54608 controller. I have modified the "simple match interrupt" demo code of ctimer module to capture a square wave of freq(20-70 Hz) at pin P2_0 of CT1_CP0(Timer 1 , channel 0). The error seems to be slightly on the higher side. I have triggered capture on both the edges so for a 50 Hz signal i would get 100 Hz output. I am expecting an accuracy of +-0.005 Hz. I have tried with 48 MHz as well as 96 MHz APB Clock frequency but still unable to acheive the desired accuracy. I have attached the code and test results for reference. Please help.


Thanks and best regards,