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Diffstat (limited to 'libopencm3/lib/stm32/common/spi_common_l1f124.c')
| -rw-r--r-- | libopencm3/lib/stm32/common/spi_common_l1f124.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/libopencm3/lib/stm32/common/spi_common_l1f124.c b/libopencm3/lib/stm32/common/spi_common_l1f124.c new file mode 100644 index 0000000..6345350 --- /dev/null +++ b/libopencm3/lib/stm32/common/spi_common_l1f124.c @@ -0,0 +1,137 @@ +/** @addtogroup spi_file + +@author @htmlonly © @endhtmlonly 2009 +Uwe Hermann <uwe@hermann-uwe.de> +@author @htmlonly © @endhtmlonly 2012 +Ken Sarkies <ksarkies@internode.on.net> + +Devices can have up to three SPI peripherals. The common 4-wire full-duplex +mode of operation is supported, along with 3-wire variants using unidirectional +communication modes or half-duplex bidirectional communication. A variety of +options allows many of the SPI variants to be supported. Multimaster operation +is also supported. A CRC can be generated and checked in hardware. + +@note Some JTAG pins need to be remapped if SPI is to be used. + +@note The I2S protocol shares the SPI hardware so the two protocols cannot be +used at the same time on the same peripheral. + +Example: 1Mbps, positive clock polarity, leading edge trigger, 8-bit words, +LSB first. +@code + spi_init_master(SPI1, 1000000, SPI_CR1_CPOL_CLK_TO_0_WHEN_IDLE, + SPI_CR1_CPHA_CLK_TRANSITION_1, SPI_CR1_DFF_8BIT, + SPI_CR1_LSBFIRST); + spi_write(SPI1, 0x55); // 8-bit write + spi_write(SPI1, 0xaa88); // 16-bit write + reg8 = spi_read(SPI1); // 8-bit read + reg16 = spi_read(SPI1); // 16-bit read +@endcode + +@todo need additional functions to aid ISRs in retrieving status + +*/ + +/* + * This file is part of the libopencm3 project. + * + * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de> + * + * This library is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this library. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <libopencm3/stm32/spi.h> +#include <libopencm3/stm32/rcc.h> + +/* + * SPI and I2S code. + * + * Examples: + * spi_init_master(SPI1, 1000000, SPI_CR1_CPOL_CLK_TO_0_WHEN_IDLE, + * SPI_CR1_CPHA_CLK_TRANSITION_1, SPI_CR1_DFF_8BIT, + * SPI_CR1_LSBFIRST); + * spi_write(SPI1, 0x55); // 8-bit write + * spi_write(SPI1, 0xaa88); // 16-bit write + * reg8 = spi_read(SPI1); // 8-bit read + * reg16 = spi_read(SPI1); // 16-bit read + */ + +/**@{*/ + +/*---------------------------------------------------------------------------*/ +/** @brief Configure the SPI as Master. + +The SPI peripheral is configured as a master with communication parameters +baudrate, data format 8/16 bits, frame format lsb/msb first, clock polarity +and phase. The SPI enable, CRC enable and CRC next controls are not affected. +These must be controlled separately. + +@todo NSS pin handling. + +@param[in] spi Unsigned int32. SPI peripheral identifier @ref spi_reg_base. +@param[in] br Unsigned int32. Baudrate @ref spi_baudrate. +@param[in] cpol Unsigned int32. Clock polarity @ref spi_cpol. +@param[in] cpha Unsigned int32. Clock Phase @ref spi_cpha. +@param[in] dff Unsigned int32. Data frame format 8/16 bits @ref spi_dff. +@param[in] lsbfirst Unsigned int32. Frame format lsb/msb first @ref +spi_lsbfirst. +@returns int. Error code. +*/ + +int spi_init_master(uint32_t spi, uint32_t br, uint32_t cpol, uint32_t cpha, + uint32_t dff, uint32_t lsbfirst) +{ + uint32_t reg32 = SPI_CR1(spi); + + /* Reset all bits omitting SPE, CRCEN and CRCNEXT bits. */ + reg32 &= SPI_CR1_SPE | SPI_CR1_CRCEN | SPI_CR1_CRCNEXT; + + reg32 |= SPI_CR1_MSTR; /* Configure SPI as master. */ + + reg32 |= br; /* Set baud rate bits. */ + reg32 |= cpol; /* Set CPOL value. */ + reg32 |= cpha; /* Set CPHA value. */ + reg32 |= dff; /* Set data format (8 or 16 bits). */ + reg32 |= lsbfirst; /* Set frame format (LSB- or MSB-first). */ + + /* TODO: NSS pin handling. */ + + SPI_CR1(spi) = reg32; + + return 0; /* TODO */ +} + +/*---------------------------------------------------------------------------*/ +/** @brief SPI Set Data Frame Format to 8 bits + +@param[in] spi Unsigned int32. SPI peripheral identifier @ref spi_reg_base. +*/ + +void spi_set_dff_8bit(uint32_t spi) +{ + SPI_CR1(spi) &= ~SPI_CR1_DFF; +} + +/*---------------------------------------------------------------------------*/ +/** @brief SPI Set Data Frame Format to 16 bits + +@param[in] spi Unsigned int32. SPI peripheral identifier @ref spi_reg_base. +*/ + +void spi_set_dff_16bit(uint32_t spi) +{ + SPI_CR1(spi) |= SPI_CR1_DFF; +} + +/**@}*/ |