From a7a3770d5198d26c963127094a18175696f04827 Mon Sep 17 00:00:00 2001 From: Uwe Hermann Date: Wed, 30 Dec 2009 23:09:14 +0100 Subject: Add initial SPI code. 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. --- lib/Makefile | 2 +- lib/spi.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 65 insertions(+), 1 deletion(-) create mode 100644 lib/spi.c (limited to 'lib') diff --git a/lib/Makefile b/lib/Makefile index 8dd2a08..855aa9b 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -27,7 +27,7 @@ CFLAGS = -Os -g -Wall -Wextra -I../include -fno-common \ -mcpu=cortex-m3 -mthumb -Wstrict-prototypes # ARFLAGS = rcsv ARFLAGS = rcs -OBJS = rcc.o gpio.o usart.o adc.o +OBJS = rcc.o gpio.o usart.o adc.o spi.o # Be silent per default, but 'make V=1' will show all compiler calls. ifneq ($(V),1) diff --git a/lib/spi.c b/lib/spi.c new file mode 100644 index 0000000..02936ee --- /dev/null +++ b/lib/spi.c @@ -0,0 +1,64 @@ +/* + * This file is part of the libopenstm32 project. + * + * Copyright (C) 2009 Uwe Hermann + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#include + +/* + * 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 + */ + +int spi_init_master(u32 spi, u32 br, u32 cpol, u32 cpha, u32 dff, u32 lsbfirst) +{ + u32 reg32 = 0; + + 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-first or MSB-first). */ + + /* TODO: NSS pin handling. */ + + /* TODO: Set MSTR and SPE bits. */ + + SPI_CR1(spi) = reg32; + + return 0; /* TODO */ +} + +void spi_write(u32 spi, u16 data) +{ + /* Write data (8 or 16 bits, depending on DFF) into DR. */ + SPI_DR(spi) = data; +} + +u16 spi_read(u32 spi) +{ + /* Read the data (8 or 16 bits, depending on DFF bit) from DR. */ + return SPI_DR(spi); +} -- cgit v1.2.3