Hello World example for interfacing up to four rotary encoders to the STM32's timer/counter hardware, without interrupts.

Dependencies:   mbed-dev

Revision:
1:cd7b42c99ff8
diff -r ee5cb967aa17 -r cd7b42c99ff8 Encoder/EncoderMspInitL4.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Encoder/EncoderMspInitL4.cpp	Sun Oct 04 11:58:58 2015 +0000
@@ -0,0 +1,86 @@
+#include "mbed.h"
+/*
+ * HAL_TIM_Encoder_MspInit()
+ * Overrides the __weak function stub in stm32f4xx_hal_tim.h
+ *
+ * Edit the below for your preferred pin wiring & pullup/down
+ * I have encoder common at 3V3, using GPIO_PULLDOWN on inputs.
+ * Encoder A&B outputs connected directly to GPIOs.
+ *
+ * http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/DM00108832.pdf
+ * Table 15 has GPIOx AFx pinouts
+ *
+ * TIM1_CH1: AF1 @ PA8, PE9
+ * TIM1_CH2: AF1 @ PA9, PE11
+ *
+ * TIM2_CH1: AF1 @ PA0, PA5, PA15
+ * TIM2_CH2: AF1 @ PA1, PB3
+ *
+ * TIM3_CH1: AF2 @ PA6, PB4, PC6, PE3
+ * TIM3_CH2: AF2 @ PA7, PB5, PC7, PE4
+ *
+ * TIM4_CH1: AF2 @ PB6, PD12
+ * TIM4_CH2: AF2 @ PB7, PD13
+ *
+ * TIM5_CH1: AF2 @ PA0, PF6
+ * TIM5_CH2: AF2 @ PA1, PF7
+ *
+ */
+
+#ifdef TARGET_STM32L4
+void HAL_TIM_Encoder_MspInit(TIM_HandleTypeDef *htim)
+{
+    GPIO_InitTypeDef GPIO_InitStruct;
+
+    if (htim->Instance == TIM1) {       //PA8 PA9 = Nucleo D7 D8
+        __TIM1_CLK_ENABLE();
+        __GPIOA_CLK_ENABLE();
+        GPIO_InitStruct.Pin = GPIO_PIN_8 | GPIO_PIN_9;
+        GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
+        GPIO_InitStruct.Pull = GPIO_PULLDOWN;
+        GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
+        GPIO_InitStruct.Alternate = GPIO_AF1_TIM1;
+        HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
+    }
+    else if (htim->Instance == TIM2) {  //PA0 PA1 = Nucleo A0 A1
+        __TIM2_CLK_ENABLE();
+        __GPIOA_CLK_ENABLE();
+        GPIO_InitStruct.Pin = GPIO_PIN_0 | GPIO_PIN_1;
+        GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
+        GPIO_InitStruct.Pull = GPIO_PULLDOWN;
+        GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
+        GPIO_InitStruct.Alternate = GPIO_AF1_TIM2;
+        HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
+    }
+    else if (htim->Instance == TIM3) {  //PB4 PB5 = Nucleo D5 D4
+        __TIM3_CLK_ENABLE();
+        __GPIOB_CLK_ENABLE();
+        GPIO_InitStruct.Pin = GPIO_PIN_4 | GPIO_PIN_5;
+        GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
+        GPIO_InitStruct.Pull = GPIO_PULLDOWN;
+        GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
+        GPIO_InitStruct.Alternate = GPIO_AF2_TIM3;
+        HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
+    }
+    else if (htim->Instance == TIM4) { // PB6 PB7 = Nucleo D10 MORPHO_PB7
+        __TIM4_CLK_ENABLE();
+        __GPIOB_CLK_ENABLE();
+        GPIO_InitStruct.Pin = GPIO_PIN_6 | GPIO_PIN_7;
+        GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
+        GPIO_InitStruct.Pull = GPIO_PULLDOWN;
+        GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
+        GPIO_InitStruct.Alternate = GPIO_AF2_TIM4;
+        HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
+    }
+    else if (htim->Instance == TIM5) { // here for completeness, mbed sytem timer uses this
+        __TIM5_CLK_ENABLE();
+        __GPIOA_CLK_ENABLE();
+        GPIO_InitStruct.Pin = GPIO_PIN_0 | GPIO_PIN_1;
+        GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
+        GPIO_InitStruct.Pull = GPIO_PULLDOWN;
+        GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
+        GPIO_InitStruct.Alternate = GPIO_AF2_TIM5;
+        HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
+    }
+}
+#endif
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