![](/media/cache/img/default_profile.jpg.50x50_q85.jpg)
Demo program to read ABZ Quadrature Encoder in Hardware on the Nucleo F401RE
main.cpp@0:25c34018702c, 2014-11-17 (annotated)
- Committer:
- Nigel945426
- Date:
- Mon Nov 17 19:17:21 2014 +0000
- Revision:
- 0:25c34018702c
Working version of Hardware Quadrature ABZ reader
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
Nigel945426 | 0:25c34018702c | 1 | #include "mbed.h" |
Nigel945426 | 0:25c34018702c | 2 | |
Nigel945426 | 0:25c34018702c | 3 | // Hardware Quadrature Encoder ABZ for Nucleo F401RE |
Nigel945426 | 0:25c34018702c | 4 | // Output on debug port to host PC @ 9600 baud |
Nigel945426 | 0:25c34018702c | 5 | // |
Nigel945426 | 0:25c34018702c | 6 | // By Nigel Webb, November 2014 |
Nigel945426 | 0:25c34018702c | 7 | |
Nigel945426 | 0:25c34018702c | 8 | /* Connections |
Nigel945426 | 0:25c34018702c | 9 | PA_0 = Encoder A |
Nigel945426 | 0:25c34018702c | 10 | PA_1 = Encoder B |
Nigel945426 | 0:25c34018702c | 11 | PA_4 = Encoder Z |
Nigel945426 | 0:25c34018702c | 12 | */ |
Nigel945426 | 0:25c34018702c | 13 | |
Nigel945426 | 0:25c34018702c | 14 | InterruptIn ZPulse(PA_4) ; // Setup Interrupt for Z Pulse |
Nigel945426 | 0:25c34018702c | 15 | |
Nigel945426 | 0:25c34018702c | 16 | void EncoderInitialise(void) { |
Nigel945426 | 0:25c34018702c | 17 | // configure GPIO PA0 & PA1 as inputs for Encoder |
Nigel945426 | 0:25c34018702c | 18 | RCC->AHB1ENR |= 0x00000001; // Enable clock for GPIOA |
Nigel945426 | 0:25c34018702c | 19 | |
Nigel945426 | 0:25c34018702c | 20 | GPIOA->MODER |= GPIO_MODER_MODER0_1 | GPIO_MODER_MODER1_1 ; //PA0 & PA1 as Alternate Function /*!< GPIO port mode register, Address offset: 0x00 */ |
Nigel945426 | 0:25c34018702c | 21 | GPIOA->OTYPER |= GPIO_OTYPER_OT_0 | GPIO_OTYPER_OT_1 ; //PA0 & PA1 as Inputs /*!< GPIO port output type register, Address offset: 0x04 */ |
Nigel945426 | 0:25c34018702c | 22 | GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR0 | GPIO_OSPEEDER_OSPEEDR1 ; // Low speed /*!< GPIO port output speed register, Address offset: 0x08 */ |
Nigel945426 | 0:25c34018702c | 23 | GPIOA->PUPDR |= GPIO_PUPDR_PUPDR0_1 | GPIO_PUPDR_PUPDR1_1 ; // Pull Down /*!< GPIO port pull-up/pull-down register, Address offset: 0x0C */ |
Nigel945426 | 0:25c34018702c | 24 | GPIOA->AFR[0] |= 0x00000011 ; // AF01 for PA0 & PA1 /*!< GPIO alternate function registers, Address offset: 0x20-0x24 */ |
Nigel945426 | 0:25c34018702c | 25 | GPIOA->AFR[1] |= 0x00000000 ; // /*!< GPIO alternate function registers, Address offset: 0x20-0x24 */ |
Nigel945426 | 0:25c34018702c | 26 | |
Nigel945426 | 0:25c34018702c | 27 | // configure TIM2 as Encoder input |
Nigel945426 | 0:25c34018702c | 28 | RCC->APB1ENR |= 0x00000001; // Enable clock for TIM2 |
Nigel945426 | 0:25c34018702c | 29 | |
Nigel945426 | 0:25c34018702c | 30 | TIM2->CR1 = 0x0001; // CEN(Counter ENable)='1' < TIM control register 1 |
Nigel945426 | 0:25c34018702c | 31 | TIM2->SMCR = 0x0003; // SMS='011' (Encoder mode 3) < TIM slave mode control register |
Nigel945426 | 0:25c34018702c | 32 | TIM2->CCMR1 = 0xF1F1; // CC1S='01' CC2S='01' < TIM capture/compare mode register 1 |
Nigel945426 | 0:25c34018702c | 33 | TIM2->CCMR2 = 0x0000; // < TIM capture/compare mode register 2 |
Nigel945426 | 0:25c34018702c | 34 | TIM2->CCER = 0x0011; // CC1P CC2P < TIM capture/compare enable register |
Nigel945426 | 0:25c34018702c | 35 | TIM2->PSC = 0x0000; // Prescaler = (0+1) < TIM prescaler |
Nigel945426 | 0:25c34018702c | 36 | TIM2->ARR = 0xffffffff; // reload at 0xfffffff < TIM auto-reload register |
Nigel945426 | 0:25c34018702c | 37 | |
Nigel945426 | 0:25c34018702c | 38 | TIM2->CNT = 0x0000; //reset the counter before we use it |
Nigel945426 | 0:25c34018702c | 39 | } |
Nigel945426 | 0:25c34018702c | 40 | |
Nigel945426 | 0:25c34018702c | 41 | // Z Pulse routine |
Nigel945426 | 0:25c34018702c | 42 | void ZeroEncoderCount() { |
Nigel945426 | 0:25c34018702c | 43 | TIM2->CNT=0 ; //reset count to zero |
Nigel945426 | 0:25c34018702c | 44 | } |
Nigel945426 | 0:25c34018702c | 45 | |
Nigel945426 | 0:25c34018702c | 46 | int main() { |
Nigel945426 | 0:25c34018702c | 47 | EncoderInitialise() ; |
Nigel945426 | 0:25c34018702c | 48 | |
Nigel945426 | 0:25c34018702c | 49 | ZPulse.rise(&ZeroEncoderCount) ; //Setup Interrupt for rising edge of Z pulse |
Nigel945426 | 0:25c34018702c | 50 | ZPulse.mode(PullDown) ; // Set input as pull down |
Nigel945426 | 0:25c34018702c | 51 | |
Nigel945426 | 0:25c34018702c | 52 | unsigned int EncoderPosition ; |
Nigel945426 | 0:25c34018702c | 53 | |
Nigel945426 | 0:25c34018702c | 54 | while (true) { |
Nigel945426 | 0:25c34018702c | 55 | // Print Encoder Quadrature count to debug port every 0.5 seconds |
Nigel945426 | 0:25c34018702c | 56 | EncoderPosition = TIM2->CNT ; // Get current position from Encoder |
Nigel945426 | 0:25c34018702c | 57 | printf("Encoder Position %i\r\n", EncoderPosition); |
Nigel945426 | 0:25c34018702c | 58 | wait(0.5); |
Nigel945426 | 0:25c34018702c | 59 | } |
Nigel945426 | 0:25c34018702c | 60 | |
Nigel945426 | 0:25c34018702c | 61 | |
Nigel945426 | 0:25c34018702c | 62 | } |