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hal/spi_api.h
- Committer:
- amithy
- Date:
- 2017-11-09
- Revision:
- 178:c26431f84b0d
- Parent:
- 149:156823d33999
- Child:
- 167:e84263d55307
File content as of revision 178:c26431f84b0d:
/** \addtogroup hal */ /** @{*/ /* mbed Microcontroller Library * Copyright (c) 2006-2013 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef MBED_SPI_API_H #define MBED_SPI_API_H #include "device.h" #include "hal/dma_api.h" #include "hal/buffer.h" #if DEVICE_SPI #define SPI_EVENT_ERROR (1 << 1) #define SPI_EVENT_COMPLETE (1 << 2) #define SPI_EVENT_RX_OVERFLOW (1 << 3) #define SPI_EVENT_ALL (SPI_EVENT_ERROR | SPI_EVENT_COMPLETE | SPI_EVENT_RX_OVERFLOW) #define SPI_EVENT_INTERNAL_TRANSFER_COMPLETE (1 << 30) // Internal flag to report that an event occurred #define SPI_FILL_WORD (0xFFFF) #if DEVICE_SPI_ASYNCH /** Asynch SPI HAL structure */ typedef struct { struct spi_s spi; /**< Target specific SPI structure */ struct buffer_s tx_buff; /**< Tx buffer */ struct buffer_s rx_buff; /**< Rx buffer */ } spi_t; #else /** Non-asynch SPI HAL structure */ typedef struct spi_s spi_t; #endif #ifdef __cplusplus extern "C" { #endif /** * \defgroup hal_GeneralSPI SPI Configuration Functions * @{ */ /** Initialize the SPI peripheral * * Configures the pins used by SPI, sets a default format and frequency, and enables the peripheral * @param[out] obj The SPI object to initialize * @param[in] mosi The pin to use for MOSI * @param[in] miso The pin to use for MISO * @param[in] sclk The pin to use for SCLK * @param[in] ssel The pin to use for SSEL */ void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel); /** Release a SPI object * * TODO: spi_free is currently unimplemented * This will require reference counting at the C++ level to be safe * * Return the pins owned by the SPI object to their reset state * Disable the SPI peripheral * Disable the SPI clock * @param[in] obj The SPI object to deinitialize */ void spi_free(spi_t *obj); /** Configure the SPI format * * Set the number of bits per frame, configure clock polarity and phase, shift order and master/slave mode. * The default bit order is MSB. * @param[in,out] obj The SPI object to configure * @param[in] bits The number of bits per frame * @param[in] mode The SPI mode (clock polarity, phase, and shift direction) * @param[in] slave Zero for master mode or non-zero for slave mode */ void spi_format(spi_t *obj, int bits, int mode, int slave); /** Set the SPI baud rate * * Actual frequency may differ from the desired frequency due to available dividers and bus clock * Configures the SPI peripheral's baud rate * @param[in,out] obj The SPI object to configure * @param[in] hz The baud rate in Hz */ void spi_frequency(spi_t *obj, int hz); /**@}*/ /** * \defgroup SynchSPI Synchronous SPI Hardware Abstraction Layer * @{ */ /** Write a byte out in master mode and receive a value * * @param[in] obj The SPI peripheral to use for sending * @param[in] value The value to send * @return Returns the value received during send */ int spi_master_write(spi_t *obj, int value); /** Check if a value is available to read * * @param[in] obj The SPI peripheral to check * @return non-zero if a value is available */ int spi_slave_receive(spi_t *obj); /** Get a received value out of the SPI receive buffer in slave mode * * Blocks until a value is available * @param[in] obj The SPI peripheral to read * @return The value received */ int spi_slave_read(spi_t *obj); /** Write a value to the SPI peripheral in slave mode * * Blocks until the SPI peripheral can be written to * @param[in] obj The SPI peripheral to write * @param[in] value The value to write */ void spi_slave_write(spi_t *obj, int value); /** Checks if the specified SPI peripheral is in use * * @param[in] obj The SPI peripheral to check * @return non-zero if the peripheral is currently transmitting */ int spi_busy(spi_t *obj); /** Get the module number * * @param[in] obj The SPI peripheral to check * @return The module number */ uint8_t spi_get_module(spi_t *obj); /**@}*/ #if DEVICE_SPI_ASYNCH /** * \defgroup AsynchSPI Asynchronous SPI Hardware Abstraction Layer * @{ */ /** Begin the SPI transfer. Buffer pointers and lengths are specified in tx_buff and rx_buff * * @param[in] obj The SPI object that holds the transfer information * @param[in] tx The transmit buffer * @param[in] tx_length The number of bytes to transmit * @param[in] rx The receive buffer * @param[in] rx_length The number of bytes to receive * @param[in] bit_width The bit width of buffer words * @param[in] event The logical OR of events to be registered * @param[in] handler SPI interrupt handler * @param[in] hint A suggestion for how to use DMA with this transfer */ void spi_master_transfer(spi_t *obj, const void *tx, size_t tx_length, void *rx, size_t rx_length, uint8_t bit_width, uint32_t handler, uint32_t event, DMAUsage hint); /** The asynchronous IRQ handler * * Reads the received values out of the RX FIFO, writes values into the TX FIFO and checks for transfer termination * conditions, such as buffer overflows or transfer complete. * @param[in] obj The SPI object that holds the transfer information * @return Event flags if a transfer termination condition was met; otherwise 0. */ uint32_t spi_irq_handler_asynch(spi_t *obj); /** Attempts to determine if the SPI peripheral is already in use * * If a temporary DMA channel has been allocated, peripheral is in use. * If a permanent DMA channel has been allocated, check if the DMA channel is in use. If not, proceed as though no DMA * channel were allocated. * If no DMA channel is allocated, check whether tx and rx buffers have been assigned. For each assigned buffer, check * if the corresponding buffer position is less than the buffer length. If buffers do not indicate activity, check if * there are any bytes in the FIFOs. * @param[in] obj The SPI object to check for activity * @return Non-zero if the SPI port is active or zero if it is not. */ uint8_t spi_active(spi_t *obj); /** Abort an SPI transfer * * @param obj The SPI peripheral to stop */ void spi_abort_asynch(spi_t *obj); #endif /**@}*/ #ifdef __cplusplus } #endif // __cplusplus #endif // SPI_DEVICE #endif // MBED_SPI_API_H /** @}*/