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LPC43xx SCTimer hardware trigger problem

Question asked by Rick Rigby on Jan 23, 2018
Latest reply on Jan 29, 2018 by jeremyzhou

I'm trying to start the SC Timer on my LPC43xx OM13084 eval board using a hardware trigger pulse. I've wired J7 pin 12(P2_5) to a signal generating a 10us pulse. I've connected J7 pin 6(ADC_2) to a DC voltage. I've setup the SCTimer to start an 80us delay on trigger pin P2_5/GPIO5[5]. The timer match sets CTOUT8 which is set as the ADC1 trigger. With this setup I have successfully used a GPIO interrupt on P2_5/GPIO5[5], FUNC4 to trigger an ADC_1 reading. (Of course, FUNC3, directly to ADCTRIG1 works also). This tells me the signal is getting into the MCU no problem. I want to use FUNC1 of P2_5/GPIO5[5] to start the SCTimer, but I don't seem to be able to get that to work. I have tried everything I can think of and no luck. Please let me know which simple setting I've missed. I've attached my project, there are 2 build modes, just comment/uncomment the #defines at the top of the adc.c module. One build is for the GPIO mode, the other SCTimer start mode.The scope picture shows the 10us trigger in purple, two pulses from the GPIO Interrupt routine and then the ADC1 interrupt routine in yellow. The blue is the analog voltage I need to measure but that doesn't matter.


I'm not sure if I need an SCTimer_IRQ function or not & I have no idea why I can't make it work. I've used this same technique on an LPC11U68 without a problem.