a7a3770d51
For now, add the following basic SPI functions: - spi_init_master() - spi_write() - spi_read() This is incomplete and untested, yet. Also, add some more SPI bit definition macros and comments.
65 lines
1.9 KiB
C
65 lines
1.9 KiB
C
/*
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* This file is part of the libopenstm32 project.
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*
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* Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <libopenstm32.h>
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/*
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* SPI and I2S code.
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*
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* Examples:
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* spi_init_master(SPI1, 1000000, SPI_CR1_CPOL_CLK_TO_0_WHEN_IDLE,
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* SPI_CR1_CPHA_CLK_TRANSITION_1, SPI_CR1_DFF_8BIT,
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* SPI_CR1_LSBFIRST);
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* spi_write(SPI1, 0x55); // 8-bit write
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* spi_write(SPI1, 0xaa88); // 16-bit write
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* reg8 = spi_read(SPI1); // 8-bit read
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* reg16 = spi_read(SPI1); // 16-bit read
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*/
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int spi_init_master(u32 spi, u32 br, u32 cpol, u32 cpha, u32 dff, u32 lsbfirst)
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{
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u32 reg32 = 0;
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reg32 |= br; /* Set BAUD rate bits. */
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reg32 |= cpol; /* Set CPOL value. */
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reg32 |= cpha; /* Set CPHA value. */
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reg32 |= dff; /* Set data format (8 or 16 bits). */
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reg32 |= lsbfirst; /* Set frame format (LSB-first or MSB-first). */
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/* TODO: NSS pin handling. */
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/* TODO: Set MSTR and SPE bits. */
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SPI_CR1(spi) = reg32;
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return 0; /* TODO */
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}
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void spi_write(u32 spi, u16 data)
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{
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/* Write data (8 or 16 bits, depending on DFF) into DR. */
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SPI_DR(spi) = data;
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}
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u16 spi_read(u32 spi)
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{
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/* Read the data (8 or 16 bits, depending on DFF bit) from DR. */
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return SPI_DR(spi);
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}
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