main.cpp

00001 #include "mbed.h"
00002 
00003 // Hardware Quadrature Encoder ABZ for Nucleo F401RE
00004 // Output on debug port to host PC @ 9600 baud
00005 // 
00006 // By Nigel Webb, November 2014
00007 
00008 /* Encoder Connections
00009    PA8 = CH1
00010    PA9 = CH2
00011    
00012    PA6 = CH1
00013    PA7 = CH2
00014 */
00015 
00016 
00017 void EncoderInitialise(void) {
00018     // configure GPIO PA8 & PA9 as CH1 & CH2 inputs for Encoder1
00019     RCC->AHB1ENR |= 0x00000001;  // Enable clock for GPIOA
00020     GPIOA->MODER   |= GPIO_MODER_MODER8_1 | GPIO_MODER_MODER9_1 ;           //PA8 & PA9 as Alternate Function   /*!< GPIO port mode register,               Address offset: 0x00      */
00021     GPIOA->OTYPER  |= GPIO_OTYPER_OT_8 | GPIO_OTYPER_OT_9 ;                 //PA8 & PA9 as Inputs               /*!< GPIO port output type register,        Address offset: 0x04      */
00022     GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR8_1 | GPIO_OSPEEDER_OSPEEDR9_1 ; // High speed                        /*!< GPIO port output speed register,       Address offset: 0x08      */
00023     GPIOA->PUPDR   |= GPIO_PUPDR_PUPDR8_1 | GPIO_PUPDR_PUPDR9_1 ;           // Pull Down                        /*!< GPIO port pull-up/pull-down register,  Address offset: 0x0C      */
00024     //GPIOA->AFR[0]  |= 0x11000000 ;                                          //  AF02 for PA8 & PA9              /*!< GPIO alternate function registers,     Address offset: 0x20-0x24 */
00025     //GPIOA->AFR[1]  |= 0x00000011 ;                                          //                                  /*!< GPIO alternate function registers,     Address offset: 0x20-0x24 */
00026    
00027     // configure GPIO PA6 & PA7 as CH1 & CH2 inputs for Encoder2
00028     RCC->AHB1ENR |= 0x00000001;  // Enable clock for GPIOA
00029     GPIOA->MODER   |= GPIO_MODER_MODER6_1 | GPIO_MODER_MODER7_1 ;           //PA6 & PA7 as Alternate Function   /*!< GPIO port mode register,               Address offset: 0x00      */
00030     GPIOA->OTYPER  |= GPIO_OTYPER_OT_6 | GPIO_OTYPER_OT_7 ;                 //PA6 & PA7 as Inputs               /*!< GPIO port output type register,        Address offset: 0x04      */
00031     GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR6_1 | GPIO_OSPEEDER_OSPEEDR7_1 ; // High speed                        /*!< GPIO port output speed register,       Address offset: 0x08      */
00032     GPIOA->PUPDR   |= GPIO_PUPDR_PUPDR6_1 | GPIO_PUPDR_PUPDR7_1 ;           // Pull Down                        /*!< GPIO port pull-up/pull-down register,  Address offset: 0x0C      */
00033     GPIOA->AFR[0]  |= 0x22000000 ;                                          //  AF02 for PA6 & PA7              /*!< GPIO alternate function registers,     Address offset: 0x20-0x24 */
00034     GPIOA->AFR[1]  |= 0x00000011 ;                                          //                                  /*!< GPIO alternate function registers,     Address offset: 0x20-0x24 */
00035 
00036     // configure TIM1 & TIM3 as Encoder input
00037     RCC->APB2ENR |= 0x00000001;  // Enable clock for TIM1
00038     RCC->APB1ENR |= 0x00000002;  // Enable clock for TIM3
00039     
00040     TIM1->CR1   = 0x0001;     // CEN(Counter ENable)='1'     < TIM control register 1
00041     TIM1->SMCR  = 0x0001;     // SMS='001' (Encoder mode 1)  < TIM CH2 Edge
00042     TIM1->CCMR1 = 0xF1F1;     // CC1S='01' CC2S='01'         < TIM capture/compare mode register 1
00043     TIM1->CCMR2 = 0x0000;     //                             < TIM capture/compare mode register 2
00044     TIM1->CCER  = 0x0011;     // CC1P CC2P                   < TIM capture/compare enable register
00045     TIM1->PSC   = 0x0000;     // Prescaler = (0+1)           < TIM prescaler
00046     TIM1->ARR   = 0x0000000a; // reload at 10                < TIM auto-reload register
00047     TIM1->CNT   = 0x0000;     //reset the counter before we use it
00048     
00049     TIM3->CR1   = 0x0001;     // CEN(Counter ENable)='1'     < TIM control register 1
00050     TIM3->SMCR  = 0x0001;     // SMS='001' (Encoder mode 1)  < TIM CH2 Edge
00051     TIM3->CCMR1 = 0xF1F1;     // CC1S='01' CC2S='01'         < TIM capture/compare mode register 1
00052     TIM3->CCMR2 = 0x0000;     //                             < TIM capture/compare mode register 2
00053     TIM3->CCER  = 0x0011;     // CC1P CC2P                   < TIM capture/compare enable register
00054     TIM3->PSC   = 0x0000;     // Prescaler = (0+1)           < TIM prescaler
00055     TIM3->ARR   = 0x0000000a; // reload at 10                < TIM auto-reload register 
00056     TIM3->CNT   = 0x0000;     //reset the counter before we use it  
00057        
00058 }
00059 
00060 int main() {
00061     
00062     printf("\e[1;1H\e[2J");
00063     EncoderInitialise() ;
00064     
00065     uint16_t count1=0, count2=0;
00066     
00067     while (1) {
00068         // Print Encoder count to debug port every 0.5 seconds
00069         count1 = TIM1->CNT ; // Get current position from Encoder1
00070         count2 = TIM3->CNT ; // Get current position from Encoder2
00071         printf("COUNT1 %d COUNT2 %d\r\n", count1, count2);
00072         wait(0.5);
00073     }
00074       
00075 }