mbed library sources
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Superseded
This library was superseded by mbed-dev - https://os.mbed.com/users/mbed_official/code/mbed-dev/.
Development branch of the mbed library sources. This library is kept in synch with the latest changes from the mbed SDK and it is not guaranteed to work.
If you are looking for a stable and tested release, please import one of the official mbed library releases:
Import librarymbed
The official Mbed 2 C/C++ SDK provides the software platform and libraries to build your applications.
targets/hal/TARGET_NXP/TARGET_LPC176X/spi_api.c
- Committer:
- mbed_official
- Date:
- 2014-12-16
- Revision:
- 440:8a0b45cd594f
- Parent:
- 285:31249416b6f9
- Child:
- 552:a1b9575155a3
File content as of revision 440:8a0b45cd594f:
/* 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 "mbed_assert.h" #include <math.h> #include "spi_api.h" #include "cmsis.h" #include "pinmap.h" #include "mbed_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); MBED_ASSERT((int)obj->spi != NC); // 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); MBED_ASSERT(((bits >= 4) && (bits <= 16)) && (mode >= 0 && mode <= 3)); 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); }