nrf_gpiote.h

00001 /* Copyright (c) 2012 Nordic Semiconductor. All Rights Reserved.
00002  *
00003  * The information contained herein is property of Nordic Semiconductor ASA.
00004  * Terms and conditions of usage are described in detail in NORDIC
00005  * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
00006  *
00007  * Licensees are granted free, non-transferable use of the information. NO
00008  * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
00009  * the file.
00010  *
00011  */
00012 #ifndef NRF_GPIOTE_H__
00013 #define NRF_GPIOTE_H__
00014 
00015 #include "nrf.h"
00016 
00017 /**
00018 * @defgroup nrf_gpiote GPIOTE abstraction
00019 * @{
00020 * @ingroup nrf_drivers
00021 * @brief GPIOTE abstraction for configuration of channels.
00022 */
00023 
00024 
00025  /**
00026  * @enum nrf_gpiote_polarity_t
00027  * @brief Polarity for GPIOTE channel enumerator.
00028  */
00029 typedef enum
00030 {
00031   NRF_GPIOTE_POLARITY_LOTOHI = GPIOTE_CONFIG_POLARITY_LoToHi,       ///<  Low to high
00032   NRF_GPIOTE_POLARITY_HITOLO = GPIOTE_CONFIG_POLARITY_HiToLo,       ///<  High to low
00033   NRF_GPIOTE_POLARITY_TOGGLE = GPIOTE_CONFIG_POLARITY_Toggle        ///<  Toggle
00034 } nrf_gpiote_polarity_t;
00035 
00036 
00037  /**
00038  * @enum nrf_gpiote_outinit_t
00039  * @brief Initial output value for GPIOTE channel enumerator.
00040  */
00041 typedef enum
00042 {
00043   NRF_GPIOTE_INITIAL_VALUE_LOW  = GPIOTE_CONFIG_OUTINIT_Low,       ///<  Low to high
00044   NRF_GPIOTE_INITIAL_VALUE_HIGH = GPIOTE_CONFIG_OUTINIT_High       ///<  High to low
00045 } nrf_gpiote_outinit_t;
00046 
00047 
00048 /**
00049  * @brief Function for configuring GPIOTE channel as output, setting the properly desired output level.
00050  *
00051  *
00052  * @param channel_number specifies the GPIOTE channel [0:3] to configure as an output channel.
00053  * @param pin_number specifies the pin number [0:30] to use in the GPIOTE channel.
00054  * @param polarity specifies the desired polarity in the output GPIOTE channel.
00055  * @param initial_value specifies the initial value of the GPIOTE channel input after the channel configuration.
00056  */
00057 static __INLINE void nrf_gpiote_task_config(uint32_t channel_number, uint32_t pin_number, nrf_gpiote_polarity_t polarity, nrf_gpiote_outinit_t initial_value)
00058 {
00059     /* Check if the output desired is high or low */
00060     if (initial_value == NRF_GPIOTE_INITIAL_VALUE_LOW)
00061     {
00062         /* Workaround for the OUTINIT PAN. When nrf_gpiote_task_config() is called a glitch happens
00063         on the GPIO if the GPIO in question is already assigned to GPIOTE and the pin is in the 
00064         correct state in GPIOTE but not in the OUT register. */
00065         NRF_GPIO->OUTCLR = (1 << pin_number);
00066         
00067         /* Configure channel to Pin31, not connected to the pin, and configure as a tasks that will set it to proper level */
00068         NRF_GPIOTE->CONFIG[channel_number] = (GPIOTE_CONFIG_MODE_Task       << GPIOTE_CONFIG_MODE_Pos)     |
00069                                              (31UL                          << GPIOTE_CONFIG_PSEL_Pos)     |
00070                                              (GPIOTE_CONFIG_POLARITY_HiToLo << GPIOTE_CONFIG_POLARITY_Pos);                                    
00071     } 
00072     else 
00073     {
00074         /* Workaround for the OUTINIT PAN. When nrf_gpiote_task_config() is called a glitch happens
00075         on the GPIO if the GPIO in question is already assigned to GPIOTE and the pin is in the 
00076         correct state in GPIOTE but not in the OUT register. */
00077         NRF_GPIO->OUTSET = (1 << pin_number);
00078         
00079         /* Configure channel to Pin31, not connected to the pin, and configure as a tasks that will set it to proper level */
00080         NRF_GPIOTE->CONFIG[channel_number] = (GPIOTE_CONFIG_MODE_Task       << GPIOTE_CONFIG_MODE_Pos)     |
00081                                              (31UL                          << GPIOTE_CONFIG_PSEL_Pos)     |
00082                                              (GPIOTE_CONFIG_POLARITY_LoToHi << GPIOTE_CONFIG_POLARITY_Pos);
00083     }
00084 
00085     /* Three NOPs are required to make sure configuration is written before setting tasks or getting events */
00086     __NOP();
00087     __NOP();
00088     __NOP(); 
00089 
00090     /* Launch the task to take the GPIOTE channel output to the desired level */
00091     NRF_GPIOTE->TASKS_OUT[channel_number] = 1;
00092     
00093 
00094     /* Finally configure the channel as the caller expects. If OUTINIT works, the channel is configured properly. 
00095        If it does not, the channel output inheritance sets the proper level. */
00096     NRF_GPIOTE->CONFIG[channel_number] = (GPIOTE_CONFIG_MODE_Task << GPIOTE_CONFIG_MODE_Pos)     |
00097                                          ((uint32_t)pin_number    << GPIOTE_CONFIG_PSEL_Pos)     |
00098                                          ((uint32_t)polarity      << GPIOTE_CONFIG_POLARITY_Pos) |
00099                                          ((uint32_t)initial_value << GPIOTE_CONFIG_OUTINIT_Pos);
00100 
00101     /* Three NOPs are required to make sure configuration is written before setting tasks or getting events */
00102     __NOP();
00103     __NOP();
00104     __NOP(); 
00105 }
00106 
00107 /**
00108  * @brief Function for configuring GPIOTE channel as input, automatically clearing an event that appears in some cases under configuration.
00109  *
00110  * Note that when configuring the channel as input an event might be triggered. Care of disabling interrupts
00111  * for that channel is left to the user.
00112  *
00113  * @param channel_number specifies the GPIOTE channel [0:3] to configure as an input channel.
00114  * @param pin_number specifies the pin number [0:30] to use in the GPIOTE channel.
00115  * @param polarity specifies the desired polarity in the output GPIOTE channel.
00116  */
00117 static __INLINE void nrf_gpiote_event_config(uint32_t channel_number, uint32_t pin_number, nrf_gpiote_polarity_t polarity)
00118 {   
00119     /* Configure the channel as the caller expects */
00120     NRF_GPIOTE->CONFIG[channel_number] = (GPIOTE_CONFIG_MODE_Event << GPIOTE_CONFIG_MODE_Pos)     |
00121                                          ((uint32_t)pin_number     << GPIOTE_CONFIG_PSEL_Pos)     |
00122                                          ((uint32_t)polarity       << GPIOTE_CONFIG_POLARITY_Pos);
00123 
00124     /* Three NOPs are required to make sure configuration is written before setting tasks or getting events */
00125     __NOP();
00126     __NOP();
00127     __NOP();
00128     
00129     /* Clear the event that appears in some cases */
00130     NRF_GPIOTE->EVENTS_IN[channel_number] = 0; 
00131 }
00132 
00133 
00134 /**
00135  * @brief Function for unconfiguring GPIOTE channel.
00136  *
00137  *
00138  * Note that when unconfiguring the channel, the pin is configured as GPIO PIN_CNF configuration.
00139  *
00140  * @param channel_number specifies the GPIOTE channel [0:3] to unconfigure.
00141  */
00142 static __INLINE void nrf_gpiote_unconfig(uint32_t channel_number)
00143 {   
00144     /* Unonfigure the channel as the caller expects */
00145     NRF_GPIOTE->CONFIG[channel_number] = (GPIOTE_CONFIG_MODE_Disabled   << GPIOTE_CONFIG_MODE_Pos) |
00146                                          (31UL                          << GPIOTE_CONFIG_PSEL_Pos) |
00147                                          (GPIOTE_CONFIG_POLARITY_Toggle << GPIOTE_CONFIG_POLARITY_Pos);
00148 }
00149 
00150 
00151 /** @} */
00152 
00153 #endif