main.cpp

00001 #include "mbed.h"
00002 #include "FastPWM.h"
00003 
00004 
00005 //FastPWM duty(PA_3);
00006 Ticker loop;
00007 unsigned int old_velocity = 0;
00008 unsigned int velocity;
00009 AnalogOut output(A2);
00010 
00011 void EncoderInitialise(void) {
00012     // configure GPIO PA0 & PA1 as inputs for Encoder
00013     RCC->AHB1ENR |= 0x00000001;  // Enable clock for GPIOA
00014  
00015     GPIOA->MODER   |= GPIO_MODER_MODER0_1 | GPIO_MODER_MODER1_1 ;           //PA0 & PA1 as Alternate Function   /*!< GPIO port mode register,               Address offset: 0x00      */
00016     GPIOA->OTYPER  |= GPIO_OTYPER_OT_0 | GPIO_OTYPER_OT_1 ;                 //PA0 & PA1 as Inputs               /*!< GPIO port output type register,        Address offset: 0x04      */
00017     GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR0 | GPIO_OSPEEDER_OSPEEDR1 ;     // Low speed                        /*!< GPIO port output speed register,       Address offset: 0x08      */
00018     GPIOA->PUPDR   |= GPIO_PUPDR_PUPDR0_1 | GPIO_PUPDR_PUPDR1_1 ;           // Pull Down                        /*!< GPIO port pull-up/pull-down register,  Address offset: 0x0C      */
00019     GPIOA->AFR[0]  |= 0x00000011 ;                                          //  AF01 for PA0 & PA1              /*!< GPIO alternate function registers,     Address offset: 0x20-0x24 */
00020     GPIOA->AFR[1]  |= 0x00000000 ;                                          //                                  /*!< GPIO alternate function registers,     Address offset: 0x20-0x24 */
00021    
00022     // configure TIM2 as Encoder input
00023     RCC->APB1ENR |= 0x00000001;  // Enable clock for TIM2
00024  
00025     TIM2->CR1   = 0x0001;     // CEN(Counter ENable)='1'     < TIM control register 1
00026     TIM2->SMCR  = 0x0003;     // SMS='011' (Encoder mode 3)  < TIM slave mode control register
00027     TIM2->CCMR1 = 0xF1F1;     // CC1S='01' CC2S='01'         < TIM capture/compare mode register 1
00028     TIM2->CCMR2 = 0x0000;     //                             < TIM capture/compare mode register 2
00029     TIM2->CCER  = 0x0011;     // CC1P CC2P                   < TIM capture/compare enable register
00030     TIM2->PSC   = 0x0000;     // Prescaler = (0+1)           < TIM prescaler
00031     TIM2->ARR   = 0xffffffff; // reload at 0xfffffff         < TIM auto-reload register
00032   
00033     TIM2->CNT = 0x0000;  //reset the counter before we use it  
00034 }
00035  
00036 // Z Pulse routine
00037 void ZeroEncoderCount() {
00038     TIM2->CNT=0 ; //reset count to zero
00039 }
00040 
00041 void setp(void){
00042     output.write_u16((TIM2->CNT)<<4);
00043     }
00044 
00045 void print_serial(void){
00046     velocity = (TIM2->CNT);
00047     printf("%i\n\r",velocity-old_velocity);
00048     old_velocity = velocity;
00049     }
00050     
00051 int main() {
00052     EncoderInitialise() ;
00053 
00054      
00055     unsigned int EncoderPosition ;
00056     loop.attach(&setp, .000001);
00057     
00058     while (true) {
00059         // Print Encoder Quadrature count to debug port every 0.5 seconds
00060         //EncoderPosition = TIM2->CNT ; // Get current position from Encoder
00061         //printf("Encoder Position %i\r\n", EncoderPosition); 
00062         //wait(0.1);
00063     }
00064    
00065        
00066 }