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Demo program to read ABZ Quadrature Encoder in Hardware on the Nucleo F401RE
Revision 0:25c34018702c, committed 2014-11-17
- Comitter:
- Nigel945426
- Date:
- Mon Nov 17 19:17:21 2014 +0000
- Commit message:
- Working version of Hardware Quadrature ABZ reader
Changed in this revision
main.cpp | Show annotated file Show diff for this revision Revisions of this file |
mbed.bld | Show annotated file Show diff for this revision Revisions of this file |
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Mon Nov 17 19:17:21 2014 +0000 @@ -0,0 +1,62 @@ +#include "mbed.h" + +// Hardware Quadrature Encoder ABZ for Nucleo F401RE +// Output on debug port to host PC @ 9600 baud +// +// By Nigel Webb, November 2014 + +/* Connections + PA_0 = Encoder A + PA_1 = Encoder B + PA_4 = Encoder Z +*/ + +InterruptIn ZPulse(PA_4) ; // Setup Interrupt for Z Pulse + +void EncoderInitialise(void) { + // configure GPIO PA0 & PA1 as inputs for Encoder + RCC->AHB1ENR |= 0x00000001; // Enable clock for GPIOA + + GPIOA->MODER |= GPIO_MODER_MODER0_1 | GPIO_MODER_MODER1_1 ; //PA0 & PA1 as Alternate Function /*!< GPIO port mode register, Address offset: 0x00 */ + GPIOA->OTYPER |= GPIO_OTYPER_OT_0 | GPIO_OTYPER_OT_1 ; //PA0 & PA1 as Inputs /*!< GPIO port output type register, Address offset: 0x04 */ + GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR0 | GPIO_OSPEEDER_OSPEEDR1 ; // Low speed /*!< GPIO port output speed register, Address offset: 0x08 */ + GPIOA->PUPDR |= GPIO_PUPDR_PUPDR0_1 | GPIO_PUPDR_PUPDR1_1 ; // Pull Down /*!< GPIO port pull-up/pull-down register, Address offset: 0x0C */ + GPIOA->AFR[0] |= 0x00000011 ; // AF01 for PA0 & PA1 /*!< GPIO alternate function registers, Address offset: 0x20-0x24 */ + GPIOA->AFR[1] |= 0x00000000 ; // /*!< GPIO alternate function registers, Address offset: 0x20-0x24 */ + + // configure TIM2 as Encoder input + RCC->APB1ENR |= 0x00000001; // Enable clock for TIM2 + + TIM2->CR1 = 0x0001; // CEN(Counter ENable)='1' < TIM control register 1 + TIM2->SMCR = 0x0003; // SMS='011' (Encoder mode 3) < TIM slave mode control register + TIM2->CCMR1 = 0xF1F1; // CC1S='01' CC2S='01' < TIM capture/compare mode register 1 + TIM2->CCMR2 = 0x0000; // < TIM capture/compare mode register 2 + TIM2->CCER = 0x0011; // CC1P CC2P < TIM capture/compare enable register + TIM2->PSC = 0x0000; // Prescaler = (0+1) < TIM prescaler + TIM2->ARR = 0xffffffff; // reload at 0xfffffff < TIM auto-reload register + + TIM2->CNT = 0x0000; //reset the counter before we use it +} + +// Z Pulse routine +void ZeroEncoderCount() { + TIM2->CNT=0 ; //reset count to zero +} + +int main() { + EncoderInitialise() ; + + ZPulse.rise(&ZeroEncoderCount) ; //Setup Interrupt for rising edge of Z pulse + ZPulse.mode(PullDown) ; // Set input as pull down + + unsigned int EncoderPosition ; + + while (true) { + // Print Encoder Quadrature count to debug port every 0.5 seconds + EncoderPosition = TIM2->CNT ; // Get current position from Encoder + printf("Encoder Position %i\r\n", EncoderPosition); + wait(0.5); + } + + +} \ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Mon Nov 17 19:17:21 2014 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/031413cf7a89 \ No newline at end of file