napoleon leoni
/
PinDetect_Debounce_Library_Test
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Dependencies: C12832_lcd PinDetect mbed
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Bootcamp-Pushbutton_Debounce_Interrupt
by 
avnish aggarwal
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main.cpp
00001 #include "mbed.h" 00002 #include "PinDetect.h" 00003 #include "C12832_lcd.h" 00004 00005 //Napoleon Leoni 00006 //***************************************************************************// 00007 //Test program for debounce on interrupt. Here I test the PinDetect Library // 00008 //To check whether indeed the library is attaching the debounced pin to an // 00009 //interrupt. The conclusion as shown below is that it is NOT!, the PinDetect // 00010 //has some nice features like key_pressed or key_pressedheld detection // 00011 //but they are all working on polling the specified debounced pin on a Timer // 00012 //interrupt, which by default is set every 20 ms. This is not the same as // 00013 //trigering an Interrupt on a leading or trailing edge of GPIO pin // 00014 // 00015 // 00016 // TESTS RUN // 00017 // I print to the LCD three important LPC1768 registers: 00018 // ISER0..Interrupt set Enable register(address 0xE000E100), for this program 00019 // the important bits are #4..Timer 3 interrupt and #21 External interrupt 3. 00020 // Note that all GPIO interrupts are attached to the External Interrupt 3 00021 // hardware EINT3. contents of ISER0 are accesible via: *(NVIC->ISER) 00022 // 00023 // IntEnR..GPIO interrupt enable on rising, shows which pins are attached to EINT3 00024 // on their rising edge (these are only for mbed pins mapped to LPC pins on Port 0) 00025 // its contents are available using th macro LPC_GPIOINT->IO0IntEnR 00026 // IntEnF..GPIO interrupt enable on falling, shows which pins are attached to EINT3 00027 // on their falling edge (these are only for mbed pins mapped to LPC pins on Port 0) 00028 // its contents are available using th macro LPC_GPIOINT->IO0IntEnF 00029 // 00030 // Note the mapping below of MBED pins to the IntEnR/IntEnF bits: 00031 // IntEnR/IntEnF bit LPC GPIO MBED GPIO PIN 00032 // 0 P[0].0 p9 00033 // 1 P[0].1 p10 00034 // 4 P[0].4 p30 00035 // 5 P[0].5 p29 00036 // 6 P[0].6 p8 00037 // 7 P[0].7 p7 00038 // 8 P[0].8 p6 00039 // 9 P[0].9 p5 00040 // 10 P[0].10 p28 00041 // 11 P[0].11 p27 00042 // 12 P[0].12 p27 00043 // 15 P[0].15 p13 00044 // 16 P[0].16 p14 00045 // 17 P[0].17 p12 00046 // 18 P[0].18 p11 00047 // 23 P[0].23 p15 00048 // 24 P[0].24 p16 00049 // 25 P[0].25 p17 00050 // 26 P[0].26 p18 00051 // 30 P[0].30 p19 00052 // 31 P[0].31 p20 00053 //*********************************************************************************** 00054 // Test description Resulting Register Values Analysis 00055 // 1 DIRECTINT not defined ISER0 0x0000 0010 No GPIO interrupts enabled nor attached 00056 // so only pinDetect(14) IO0IntEnR 0x0000 0000 only TIMER 3 Interrupt enabled so the pinDetect 00057 // is used IO0IntEnF 0x0000 0000 libary is simply polling the pin on a timer interrupt and 00058 // debouncing it. 00059 // 00060 // 2 DIRECTINT defined ISER0 0x0020 0010(when enabled) GPIO interrupt is enabled and disabled periodically 00061 // 0x0000 0010(when disabled) when disabled the joystick up/down motion does not trigger 00062 // so we define InterruptIn IO0IntEnR 0x0080 0000 LED1 as expected, however the pindetect functionality continues 00063 // on pins 12 and 15 IO0IntEnF 0x0002 0000 to work a further confirmation that the library is not working with 00064 // an interrupt on the GPIO specified pin. Note that p15 is attached to 00065 // a rising edge GPIO interrupt and p12 to a falling edge interrupt. 00066 //*********************************************************************************** 00067 00068 #define DIRECTINT //constant to compare interrupt registers when using pindetect vs. using InterrupIn library 00069 00070 DigitalOut myled(LED1); 00071 DigitalOut myled2(LED2); 00072 DigitalOut myled3(LED3); 00073 DigitalOut myled4(LED4); 00074 C12832_LCD lcd; 00075 00076 #ifdef DIRECTINT 00077 InterruptIn down(p12); // DOWN of joystickn note that mbed p12 corresponds to lpc P0[17], should appear as 0x0002 0000 in register LPC_GPIOINT->IO0IntEnR/F 00078 InterruptIn fire(p15); // up of joystickn note that mbed p15 corresponds to lpc P0[23], should appear as 0x0080 0000 in register LPC_GPIOINT->IO0IntEnR/F 00079 #endif 00080 00081 00082 PinDetect pb(p14); // center of joystickn note that mbed p14 corresponds to lpc P0[16] should appear as 0x0001 0000 in register LPC_GPIOINT->IO0IntEnR/F 00083 00084 void ISR1() { //interrupt service routine used to turn on LED 1 on rising edge of joystick up 00085 myled = 1; 00086 } 00087 00088 void ISR2() { //interrupt service routing used to turn off LED 1 on falling 00089 myled = 0; 00090 } 00091 00092 // SPST Pushbutton debounced count demo using interrupts and callback 00093 // no external PullUp resistor needed 00094 // Pushbutton from P8 to GND. 00095 // A pb hit generates an interrupt and activates the callback function 00096 // after the switch is debounced 00097 00098 // Global count variable 00099 int volatile count=0; 00100 00101 // Callback routine is interrupt activated by a debounced pb hit 00102 void pb_hit_callback (void) { 00103 count++; 00104 myled4 = count & 0x01; 00105 myled3 = (count & 0x02)>>1; 00106 myled2 = (count & 0x04)>>2; 00107 } 00108 00109 int main() 00110 { 00111 #ifdef DIRECTINT 00112 fire.rise(&ISR1); 00113 down.fall(&ISR2); 00114 #endif 00115 // Use internal pullup for pushbutton 00116 //pb.mode(PullUp); // don't do this for app board 00117 // Delay for initial pullup to take effect 00118 wait(.01); 00119 // Setup Interrupt callback function for a pb hit 00120 pb.attach_deasserted(&pb_hit_callback); 00121 // Start sampling pb input using interrupts 00122 pb.setSampleFrequency(); 00123 00124 //Blink myled in main routine forever while responding to pb changes 00125 // via interrupts that activate the callback counter function 00126 bool disableInterrupt=false; 00127 int counter=0,tdelay=10; 00128 while (1) { 00129 wait(1); 00130 lcd.cls(); 00131 lcd.locate(0,1); 00132 lcd.printf("ISER0=%#010X",*(NVIC->ISER)); //NVIC->ISER holds the address of the ISER0 register 00133 lcd.locate(0,10); 00134 lcd.printf("IO0 INTEN R=%#010X",LPC_GPIOINT->IO0IntEnR); //This address holds GPIO interrupt attach on rise edge state. 00135 lcd.locate(0,20); 00136 lcd.printf("IO0 INTEN F=%#010X",LPC_GPIOINT->IO0IntEnF ); //This address holds GPIO interrupt attach on falling edge state 00137 00138 #ifdef DIRECTINT 00139 //This section of coe periodically (every 10 seconds) toggles the external interrupt 3 EINT3 00140 //state between enabled and disabled. This is the hardware interrupt used for th GPIO pins 00141 counter++; 00142 if(counter>=tdelay){ 00143 disableInterrupt=!disableInterrupt; 00144 if(disableInterrupt) NVIC_DisableIRQ(EINT3_IRQn); //disable EINT3 00145 if(!disableInterrupt) NVIC_EnableIRQ(EINT3_IRQn); //re-enable EINT3 00146 counter=0; 00147 } 00148 #endif 00149 } 00150 00151 }
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