app_uart.h

00001 /* Copyright (c) 2013 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 
00013 /**@file
00014  *
00015  * @defgroup app_uart UART module
00016  * @{
00017  * @ingroup app_common
00018  *
00019  * @brief UART module interface.
00020  */
00021 
00022 #ifndef APP_UART_H__
00023 #define APP_UART_H__
00024 
00025 #include <stdint.h>
00026 #include <stdbool.h>
00027 #include "nordic_global.h"
00028 #include "app_util.h "
00029 
00030 #define  UART_PIN_DISCONNECTED  0xFFFFFFFF  /**< Value indicating that no pin is connected to this UART register. */
00031 
00032 /**@brief UART Flow Control modes for the peripheral.
00033  */
00034 typedef enum
00035 {
00036     APP_UART_FLOW_CONTROL_DISABLED,         /**< UART Hw Flow Control is disabled. */
00037     APP_UART_FLOW_CONTROL_ENABLED,          /**< Standard UART Hw Flow Control is enabled. */
00038     APP_UART_FLOW_CONTROL_LOW_POWER         /**< Specialized UART Hw Flow Control is used. The Low Power setting allows the nRF51 to Power Off the UART module when CTS is in-active, and re-enabling the UART when the CTS signal becomes active. This allows the nRF51 to safe power by only using the UART module when it is needed by the remote site. */
00039 } app_uart_flow_control_t;
00040 
00041 /**@brief UART communication structure holding configuration settings for the peripheral.
00042  */
00043 typedef struct
00044 {
00045     uint8_t                 rx_pin_no;      /**< RX pin number. */
00046     uint8_t                 tx_pin_no;      /**< TX pin number. */
00047     uint8_t                 rts_pin_no;     /**< RTS pin number, only used if flow control is enabled. */
00048     uint8_t                 cts_pin_no;     /**< CTS pin number, only used if flow control is enabled. */
00049     app_uart_flow_control_t flow_control;   /**< Flow control setting, if flow control is used, the system will use low power UART mode, based on CTS signal. */
00050     bool                    use_parity;     /**< Even parity if TRUE, no parity if FALSE. */
00051     uint32_t                baud_rate;      /**< Baud rate configuration. */
00052 } app_uart_comm_params_t;
00053 
00054 /**@brief UART buffer for transmitting/receiving data.
00055  */
00056 typedef struct
00057 {
00058     uint8_t * rx_buf;                       /**< Pointer to the RX buffer. */
00059     uint32_t  rx_buf_size;                  /**< Size of the RX buffer. */
00060     uint8_t * tx_buf;                       /**< Pointer to the TX buffer. */
00061     uint32_t  tx_buf_size;                  /**< Size of the TX buffer. */
00062 } app_uart_buffers_t;
00063 
00064 /**@brief Enumeration describing current state of the UART.
00065  *
00066  * @details The connection state can be fetched by the application using the function call
00067  *          @ref app_uart_get_connection_state.
00068  *          When hardware flow control is used
00069  *          - APP_UART_CONNECTED:     Communication is ongoing.
00070  *          - APP_UART_DISCONNECTED:  No communication is ongoing.
00071  *
00072  *          When no hardware flow control is used
00073  *          - APP_UART_CONNECTED:     Always returned as bytes can always be received/transmitted.
00074  */
00075 typedef enum
00076 {
00077     APP_UART_DISCONNECTED,                  /**< State indicating that the UART is disconnected and cannot receive or transmit bytes. */
00078     APP_UART_CONNECTED                      /**< State indicating that the UART is connected and ready to receive or transmit bytes. If flow control is disabled, the state will always be connected. */
00079 } app_uart_connection_state_t;
00080 
00081 /**@brief Enumeration which defines events used by the UART module upon data reception or error.
00082  *
00083  * @details The event type is used to indicate the type of additional information in the event
00084  * @ref app_uart_evt_t.
00085  */
00086 typedef enum
00087 {
00088     APP_UART_DATA_READY,                    /**< An event indicating that UART data has been received. The data is available in the FIFO and can be fetched using @ref app_uart_get. */
00089     APP_UART_FIFO_ERROR,                    /**< An error in the FIFO module used by the app_uart module has occured. The FIFO error code is stored in app_uart_evt_t.data.error_code field. */
00090     APP_UART_COMMUNICATION_ERROR,           /**< An communication error has occured during reception. The error is stored in app_uart_evt_t.data.error_communication field. */
00091     APP_UART_TX_EMPTY,                      /**< An event indicating that UART has completed transmission of all available data in the TX FIFO. */
00092     APP_UART_DATA,                          /**< An event indicating that UART data has been received, and data is present in data field. This event is only used when no FIFO is configured. */
00093 } app_uart_evt_type_t;
00094 
00095 /**@brief Struct containing events from the UART module.
00096  *
00097  * @details The app_uart_evt_t is used to notify the application of asynchronous events when data
00098  * are received on the UART peripheral or in case an error occured during data reception.
00099  */
00100 typedef struct
00101 {
00102     app_uart_evt_type_t evt_type;           /**< Type of event. */
00103     union
00104     {
00105         uint32_t        error_communication;/**< Field used if evt_type is: APP_UART_COMMUNICATION_ERROR. This field contains the value in the ERRORSRC register for the UART peripheral. The UART_ERRORSRC_x defines from @ref nrf51_bitfields.h can be used to parse the error code. See also the nRF51 Series Reference Manual for specification. */
00106         uint32_t        error_code;         /**< Field used if evt_type is: NRF_ERROR_x. Additional status/error code if the error event type is APP_UART_FIFO_ERROR. This error code refer to errors defined in nrf_error.h. */
00107         uint8_t         value;              /**< Field used if evt_type is: NRF_ERROR_x. Additional status/error code if the error event type is APP_UART_FIFO_ERROR. This error code refer to errors defined in nrf_error.h. */
00108     } data;
00109 } app_uart_evt_t;
00110 
00111 /**@brief Function for handling app_uart event callback.
00112  *
00113  * @details Upon an event in the app_uart module this callback function will be called to notify
00114  *          the applicatioon about the event.
00115  *
00116  * @param[in]   p_app_uart_event Pointer to UART event.
00117  */
00118 typedef void (*app_uart_event_handler_t) (app_uart_evt_t * p_app_uart_event);
00119 
00120 /**@brief Macro for safe initialization of the UART module in a single user instance when using
00121  *        a FIFO together with UART.
00122  *
00123  * @param[in]   P_COMM_PARAMS   Pointer to a UART communication structure: app_uart_comm_params_t
00124  * @param[in]   RX_BUF_SIZE     Size of desired RX buffer, must be a power of 2 or ZERO (No FIFO).
00125  * @param[in]   TX_BUF_SIZE     Size of desired TX buffer, must be a power of 2 or ZERO (No FIFO).
00126  * @param[in]   EVENT_HANDLER   Event handler function to be called when an event occurs in the
00127  *                              UART module.
00128  * @param[in]   IRQ_PRIO        IRQ priority, app_irq_priority_t, for the UART module irq handler.
00129  * @param[out]  ERR_CODE        The return value of the UART initialization function will be
00130  *                              written to this parameter.
00131  *
00132  * @note Since this macro allocates a buffer and registers the module as a GPIOTE user when flow
00133  *       control is enabled, it must only be called once.
00134  */
00135 #define APP_UART_FIFO_INIT(P_COMM_PARAMS, RX_BUF_SIZE, TX_BUF_SIZE, EVT_HANDLER, IRQ_PRIO, ERR_CODE)\
00136     do                                                                                             \
00137     {                                                                                              \
00138         uint16_t           APP_UART_UID = 0;                                                       \
00139         app_uart_buffers_t buffers;                                                                \
00140         static uint8_t     rx_buf[RX_BUF_SIZE];                                                    \
00141         static uint8_t     tx_buf[TX_BUF_SIZE];                                                    \
00142                                                                                                    \
00143         buffers.rx_buf      = rx_buf;                                                              \
00144         buffers.rx_buf_size = sizeof(rx_buf);                                                      \
00145         buffers.tx_buf      = tx_buf;                                                              \
00146         buffers.tx_buf_size = sizeof(tx_buf);                                                      \
00147         ERR_CODE = app_uart_init(P_COMM_PARAMS, &buffers, EVT_HANDLER, IRQ_PRIO, &APP_UART_UID);   \
00148     } while (0)
00149 
00150 /**@brief Macro for safe initialization of the UART module in a single user instance.
00151  *
00152  * @param[in]   P_COMM_PARAMS   Pointer to a UART communication structure: app_uart_comm_params_t
00153  * @param[in]   EVENT_HANDLER   Event handler function to be called when an event occurs in the
00154  *                              UART module.
00155  * @param[in]   IRQ_PRIO        IRQ priority, app_irq_priority_t, for the UART module irq handler.
00156  * @param[out]  ERR_CODE        The return value of the UART initialization function will be
00157  *                              written to this parameter.
00158  *
00159  * @note Since this macro allocates registers the module as a GPIOTE user when flow control is
00160  *       enabled, it must only be called once.
00161  */
00162 #define APP_UART_INIT(P_COMM_PARAMS, EVT_HANDLER, IRQ_PRIO, ERR_CODE)                              \
00163     do                                                                                             \
00164     {                                                                                              \
00165         uint16_t APP_UART_UID = 0;                                                                 \
00166         ERR_CODE = app_uart_init(P_COMM_PARAMS, NULL, EVT_HANDLER, IRQ_PRIO, &APP_UART_UID);       \
00167     } while (0)
00168 
00169 /**@brief Function for initializing the UART module. Use this initialization when several instances of the UART
00170  *        module are needed.
00171  *
00172  * @details This initialization will return a UART user id for the caller. The UART user id must be
00173  *          used upon re-initialization of the UART or closing of the module for the user.
00174  *          If single instance usage is needed, the APP_UART_INIT() macro should be used instead.
00175  *
00176  * @note Normally single instance initialization should be done using the APP_UART_INIT() or
00177  *       APP_UART_INIT_FIFO() macro depending on whether the FIFO should be used by the UART, as
00178  *       that will allocate the buffers needed by the UART module (including aligning the buffer
00179  *       correctly).
00180 
00181  * @param[in]     p_comm_params     Pin and communication parameters.
00182  * @param[in]     p_buffers         RX and TX buffers, NULL is FIFO is not used.
00183  * @param[in]     error_handler     Function to be called in case of an error.
00184  * @param[in]     app_irq_priority  Interrupt priority level.
00185  * @param[in,out] p_uart_uid        User id for the UART module. The p_uart_uid must be used if
00186  *                                  re-initialization and/or closing of the UART module is needed.
00187  *                                  If the value pointed to by p_uart_uid is zero, this is
00188  *                                  considdered a first time initialization. Otherwise this is
00189  *                                  considered a re-initialization for the user with id *p_uart_uid.
00190  *
00191  * @retval      NRF_SUCCESS               If successful initialization.
00192  * @retval      NRF_ERROR_INVALID_LENGTH  If a provided buffer is not a power of two.
00193  * @retval      NRF_ERROR_NULL            If one of the provided buffers is a NULL pointer.
00194  *
00195  * Those errors are propagated by the UART module to the caller upon registration when Hardware Flow
00196  * Control is enabled. When Hardware Flow Control is not used, those errors cannot occur.
00197  * @retval      NRF_ERROR_INVALID_STATE   The GPIOTE module is not in a valid state when registering
00198  *                                        the UART module as a user.
00199  * @retval      NRF_ERROR_INVALID_PARAM   The UART module provides an invalid callback function when
00200  *                                        registering the UART module as a user.
00201  *                                        Or the value pointed to by *p_uart_uid is not a valid
00202  *                                        GPIOTE number.
00203  * @retval      NRF_ERROR_NO_MEM          GPIOTE module has reached the maximum number of users.
00204  */
00205 uint32_t app_uart_init(const app_uart_comm_params_t * p_comm_params,
00206                              app_uart_buffers_t *     p_buffers,
00207                              app_uart_event_handler_t error_handler,
00208                              app_irq_priority_t       irq_priority,
00209                              uint16_t *               p_uart_uid);
00210 
00211 /**@brief Function for getting a byte from the UART.
00212  *
00213  * @details This function will get the next byte from the RX buffer. If the RX buffer is empty
00214  *          an error code will be returned and the app_uart module will generate an event upon 
00215  *          reception of the first byte which is added to the RX buffer.
00216  *
00217  * @param[out] p_byte    Pointer to an address where next byte received on the UART will be copied.
00218  *
00219  * @retval NRF_SUCCESS          If a byte has been received and pushed to the pointer provided.
00220  * @retval NRF_ERROR_NOT_FOUND  If no byte is available in the RX buffer of the app_uart module.
00221  */
00222 uint32_t app_uart_get(uint8_t * p_byte);
00223 
00224 /**@brief Function for putting a byte on the UART.
00225  *
00226  * @details This call is non-blocking.
00227  *
00228  * @param[in] byte   Byte to be transmitted on the UART.
00229  *
00230  * @retval NRF_SUCCESS        If the byte was succesfully put on the TX buffer for transmission.
00231  * @retval NRF_ERROR_NO_MEM   If no more space is available in the TX buffer.
00232  *                            NRF_ERROR_NO_MEM may occur if flow control is enabled and CTS signal
00233  *                            is high for a long period and the buffer fills up.
00234  */
00235 uint32_t app_uart_put(uint8_t byte);
00236 
00237 /**@brief Function for getting the current state of the UART.
00238  *
00239  * @details If flow control is disabled, the state is assumed to always be APP_UART_CONNECTED.
00240  *
00241  *          When using flow control the state will be controlled by the CTS. If CTS is set active 
00242  *          by the remote side, or the app_uart module is in the process of transmitting a byte,
00243  *          app_uart is in APP_UART_CONNECTED state. If CTS is set inactive by remote side app_uart
00244  *          will not get into APP_UART_DISCONNECTED state until the last byte in the TXD register 
00245  *          is fully transmitted.
00246  *
00247  *          Internal states in the state machine are mapped to the general connected/disconnected
00248  *          states in the following ways:
00249  *
00250  *          - UART_ON    = CONNECTED
00251  *          - UART_READY = CONNECTED
00252  *          - UART_WAIT  = CONNECTED
00253  *          - UART_OFF   = DISCONNECTED.
00254  *
00255  * @param[out] p_connection_state    Current connection state of the UART.
00256  *
00257  * @retval NRF_SUCCESS  The connection state was succesfully retrieved.
00258  */
00259 uint32_t app_uart_get_connection_state(app_uart_connection_state_t * p_connection_state);
00260 
00261 /**@brief Function for flushing the RX and TX buffers (Only valid if FIFO is used).
00262  *        This function does nothing if FIFO is not used.
00263  *
00264  * @retval  NRF_SUCCESS  Flushing completed (Current implementation will always succeed).
00265  */
00266 uint32_t app_uart_flush(void);
00267 
00268 /**@brief Function for closing the UART module.
00269  *
00270  * @details This function will close any on-going UART transmissions and disable itself in the
00271  *          GPTIO module.
00272  *
00273  * @param[in] app_uart_uid  User id for the UART module. The app_uart_uid must be identical to the
00274  *                          UART id returned on initialization and which is currently in use.
00275 
00276  * @retval  NRF_SUCCESS             If successfully closed.
00277  * @retval  NRF_ERROR_INVALID_PARAM If an invalid user id is provided or the user id differs from
00278  *                                  the current active user.
00279  */
00280 uint32_t app_uart_close(uint16_t app_uart_id);
00281 
00282 
00283 #endif // APP_UART_H__
00284 
00285 /** @} */