mbed library sources
Dependents: frdm_kl05z_gpio_test
Fork of mbed-src by
vendor/NXP/LPC1768/hal/spi_api.c
- Committer:
- emilmont
- Date:
- 2013-06-14
- Revision:
- 10:3bc89ef62ce7
File content as of revision 10:3bc89ef62ce7:
/* 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. */ #include <math.h> #include "spi_api.h" #include "cmsis.h" #include "pinmap.h" #include "error.h" static const PinMap PinMap_SPI_SCLK[] = { {P0_7 , SPI_1, 2}, {P0_15, SPI_0, 2}, {P1_20, SPI_0, 3}, {P1_31, SPI_1, 2}, {NC , NC , 0} }; static const PinMap PinMap_SPI_MOSI[] = { {P0_9 , SPI_1, 2}, {P0_13, SPI_1, 2}, {P0_18, SPI_0, 2}, {P1_24, SPI_0, 3}, {NC , NC , 0} }; static const PinMap PinMap_SPI_MISO[] = { {P0_8 , SPI_1, 2}, {P0_12, SPI_1, 2}, {P0_17, SPI_0, 2}, {P1_23, SPI_0, 3}, {NC , NC , 0} }; static const PinMap PinMap_SPI_SSEL[] = { {P0_6 , SPI_1, 2}, {P0_11, SPI_1, 2}, {P0_16, SPI_0, 2}, {P1_21, SPI_0, 3}, {NC , NC , 0} }; static inline int ssp_disable(spi_t *obj); static inline int ssp_enable(spi_t *obj); void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) { // determine the SPI to use SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI); SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO); SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK); SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL); SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso); SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel); obj->spi = (LPC_SSP_TypeDef*)pinmap_merge(spi_data, spi_cntl); if ((int)obj->spi == NC) { error("SPI pinout mapping failed"); } // enable power and clocking switch ((int)obj->spi) { case SPI_0: LPC_SC->PCONP |= 1 << 21; break; case SPI_1: LPC_SC->PCONP |= 1 << 10; break; } // set default format and frequency if (ssel == NC) { spi_format(obj, 8, 0, 0); // 8 bits, mode 0, master } else { spi_format(obj, 8, 0, 1); // 8 bits, mode 0, slave } spi_frequency(obj, 1000000); // enable the ssp channel ssp_enable(obj); // pin out the spi pins pinmap_pinout(mosi, PinMap_SPI_MOSI); pinmap_pinout(miso, PinMap_SPI_MISO); pinmap_pinout(sclk, PinMap_SPI_SCLK); if (ssel != NC) { pinmap_pinout(ssel, PinMap_SPI_SSEL); } } void spi_free(spi_t *obj) {} void spi_format(spi_t *obj, int bits, int mode, int slave) { ssp_disable(obj); if (!(bits >= 4 && bits <= 16) || !(mode >= 0 && mode <= 3)) { error("SPI format error"); } int polarity = (mode & 0x2) ? 1 : 0; int phase = (mode & 0x1) ? 1 : 0; // set it up int DSS = bits - 1; // DSS (data select size) int SPO = (polarity) ? 1 : 0; // SPO - clock out polarity int SPH = (phase) ? 1 : 0; // SPH - clock out phase int FRF = 0; // FRF (frame format) = SPI uint32_t tmp = obj->spi->CR0; tmp &= ~(0xFFFF); tmp |= DSS << 0 | FRF << 4 | SPO << 6 | SPH << 7; obj->spi->CR0 = tmp; tmp = obj->spi->CR1; tmp &= ~(0xD); tmp |= 0 << 0 // LBM - loop back mode - off | ((slave) ? 1 : 0) << 2 // MS - master slave mode, 1 = slave | 0 << 3; // SOD - slave output disable - na obj->spi->CR1 = tmp; ssp_enable(obj); } void spi_frequency(spi_t *obj, int hz) { ssp_disable(obj); // setup the spi clock diveder to /1 switch ((int)obj->spi) { case SPI_0: LPC_SC->PCLKSEL1 &= ~(3 << 10); LPC_SC->PCLKSEL1 |= (1 << 10); break; case SPI_1: LPC_SC->PCLKSEL0 &= ~(3 << 20); LPC_SC->PCLKSEL0 |= (1 << 20); break; } uint32_t PCLK = SystemCoreClock; int prescaler; for (prescaler = 2; prescaler <= 254; prescaler += 2) { int prescale_hz = PCLK / prescaler; // calculate the divider int divider = floor(((float)prescale_hz / (float)hz) + 0.5f); // check we can support the divider if (divider < 256) { // prescaler obj->spi->CPSR = prescaler; // divider obj->spi->CR0 &= ~(0xFFFF << 8); obj->spi->CR0 |= (divider - 1) << 8; ssp_enable(obj); return; } } error("Couldn't setup requested SPI frequency"); } static inline int ssp_disable(spi_t *obj) { return obj->spi->CR1 &= ~(1 << 1); } static inline int ssp_enable(spi_t *obj) { return obj->spi->CR1 |= (1 << 1); } static inline int ssp_readable(spi_t *obj) { return obj->spi->SR & (1 << 2); } static inline int ssp_writeable(spi_t *obj) { return obj->spi->SR & (1 << 1); } static inline void ssp_write(spi_t *obj, int value) { while (!ssp_writeable(obj)); obj->spi->DR = value; } static inline int ssp_read(spi_t *obj) { while (!ssp_readable(obj)); return obj->spi->DR; } static inline int ssp_busy(spi_t *obj) { return (obj->spi->SR & (1 << 4)) ? (1) : (0); } int spi_master_write(spi_t *obj, int value) { ssp_write(obj, value); return ssp_read(obj); } int spi_slave_receive(spi_t *obj) { return (ssp_readable(obj) && !ssp_busy(obj)) ? (1) : (0); }; int spi_slave_read(spi_t *obj) { return obj->spi->DR; } void spi_slave_write(spi_t *obj, int value) { while (ssp_writeable(obj) == 0) ; obj->spi->DR = value; } int spi_busy(spi_t *obj) { return ssp_busy(obj); }