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45b353c6ef
The MSP430 vendor files already provide macros containing register constants and symbols (provided via linker scripts) containing addresses of peripheral registers. So lets make use of that rather than maintaining a long list of constants.
138 lines
3.2 KiB
C
138 lines
3.2 KiB
C
/*
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* Copyright (C) 2015-2016 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup cpu_msp430_f2xx_g2xx
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* @ingroup drivers_periph_spi
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* @{
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*
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* @file
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* @brief Low-level SPI driver implementation
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*
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* This SPI driver implementation does only support one single SPI device for
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* now. This is sufficient, as most MSP430 CPU's only support two serial
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* devices - one used as UART and one as SPI.
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*
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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*
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* @}
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*/
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#include <assert.h>
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#include "cpu.h"
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#include "mutex.h"
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#include "periph/spi.h"
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/**
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* @brief Mutex for locking the SPI device
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*/
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static mutex_t spi_lock = MUTEX_INIT;
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void spi_init(spi_t bus)
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{
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assert((unsigned)bus < SPI_NUMOF);
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/* reset SPI device */
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SPI_BASE->CTL1 = UCSWRST;
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SPI_BASE->CTL1 |= UCSSEL_SMCLK;
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/* trigger the pin configuration */
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spi_init_pins(bus);
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}
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void spi_init_pins(spi_t bus)
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{
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(void)bus;
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gpio_periph_mode(SPI_PIN_MISO, true);
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gpio_periph_mode(SPI_PIN_MOSI, true);
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gpio_periph_mode(SPI_PIN_CLK, true);
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}
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void spi_acquire(spi_t bus, spi_cs_t cs, spi_mode_t mode, spi_clk_t clk)
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{
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(void)bus;
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(void)cs;
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assert((unsigned)bus < SPI_NUMOF);
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assert(clk != SPI_CLK_10MHZ);
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/* lock the bus */
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mutex_lock(&spi_lock);
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/* calculate baudrate */
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uint32_t br = msp430_submain_clock_freq() / clk;
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/* make sure the is not smaller then 2 */
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if (br < 2) {
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br = 2;
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}
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SPI_BASE->BR0 = (uint8_t)br;
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SPI_BASE->BR1 = (uint8_t)(br >> 8);
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/* configure bus mode */
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/* configure mode */
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SPI_BASE->CTL0 = (UCSYNC | UCMST | UCMODE_0 | UCMSB | mode);
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/* release from software reset */
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SPI_BASE->CTL1 &= ~(UCSWRST);
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}
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void spi_release(spi_t bus)
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{
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(void)bus;
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/* put SPI device back in reset state */
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SPI_BASE->CTL1 |= UCSWRST;
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/* release the bus */
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mutex_unlock(&spi_lock);
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}
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void spi_transfer_bytes(spi_t bus, spi_cs_t cs, bool cont,
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const void *out, void *in, size_t len)
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{
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(void)bus;
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const uint8_t *out_buf = out;
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uint8_t *in_buf = in;
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assert(out_buf || in_buf);
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if (cs != SPI_CS_UNDEF) {
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gpio_clear((gpio_t)cs);
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}
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/* if we only send out data, we do this the fast way... */
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if (!in_buf) {
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for (size_t i = 0; i < len; i++) {
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while (!(SPI_IF & SPI_IE_TX_BIT)) {}
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SPI_BASE->TXBUF = out_buf[i];
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}
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/* finally we need to wait, until all transfers are complete */
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while (SPI_BASE->STAT & UCBUSY) {}
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SPI_BASE->RXBUF;
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}
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else if (!out_buf) {
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for (size_t i = 0; i < len; i++) {
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SPI_BASE->TXBUF = 0;
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while (!(SPI_IF & SPI_IE_RX_BIT)) {}
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in_buf[i] = (char)SPI_BASE->RXBUF;
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}
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}
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else {
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for (size_t i = 0; i < len; i++) {
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while (!(SPI_IF & SPI_IE_TX_BIT)) {}
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SPI_BASE->TXBUF = out_buf[i];
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while (!(SPI_IF & SPI_IE_RX_BIT)) {}
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in_buf[i] = (char)SPI_BASE->RXBUF;
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}
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}
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if ((!cont) && (cs != SPI_CS_UNDEF)) {
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gpio_set((gpio_t)cs);
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}
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}
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