mbed library sources
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targets/hal/TARGET_NXP/TARGET_LPC82X/spi_api.c
- Committer:
- mbed_official
- Date:
- 2014-10-13
- Revision:
- 346:accf433c2acf
- Parent:
- 337:6ed01c00b962
- Child:
- 356:1c135c664c6b
File content as of revision 346:accf433c2acf:
/* 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 "spi_api.h" #include "cmsis.h" #include "pinmap.h" #include "mbed_error.h" #if DEVICE_SPI static const SWM_Map SWM_SPI_SSEL[] = { {4, 16}, {5, 16}, }; static const SWM_Map SWM_SPI_SCLK[] = { {3, 24}, {4, 24}, }; static const SWM_Map SWM_SPI_MOSI[] = { {4, 0}, {5, 0}, }; static const SWM_Map SWM_SPI_MISO[] = { {4, 8}, {5, 16}, }; // bit flags for used SPIs static unsigned char spi_used = 0; static int get_available_spi(void) { int i; for (i=0; i<2; i++) { if ((spi_used & (1 << i)) == 0) return i; } return -1; } 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) { int spi_n = get_available_spi(); if (spi_n == -1) { error("No available SPI"); } obj->spi_n = spi_n; spi_used |= (1 << spi_n); obj->spi = (spi_n) ? (LPC_SPI0_Type *)(LPC_SPI1_BASE) : (LPC_SPI0_Type *)(LPC_SPI0_BASE); const SWM_Map *swm; uint32_t regVal; if (sclk != (PinName)NC) { swm = &SWM_SPI_SCLK[obj->spi_n]; regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset); LPC_SWM->PINASSIGN[swm->n] = regVal | ((sclk >> PIN_SHIFT) << swm->offset); } if (mosi != (PinName)NC) { swm = &SWM_SPI_MOSI[obj->spi_n]; regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset); LPC_SWM->PINASSIGN[swm->n] = regVal | ((mosi >> PIN_SHIFT) << swm->offset); } if (miso != (PinName)NC) { swm = &SWM_SPI_MISO[obj->spi_n]; regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset); LPC_SWM->PINASSIGN[swm->n] = regVal | ((miso >> PIN_SHIFT) << swm->offset); } if (ssel != (PinName)NC) { swm = &SWM_SPI_SSEL[obj->spi_n]; regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset); LPC_SWM->PINASSIGN[swm->n] = regVal | ((ssel >> PIN_SHIFT) << swm->offset); } // clear interrupts obj->spi->INTENCLR = 0x3f; LPC_SYSCON->SYSAHBCLKCTRL |= (1 << (11 + obj->spi_n)); LPC_SYSCON->PRESETCTRL &= ~(1 << obj->spi_n); LPC_SYSCON->PRESETCTRL |= (1 << obj->spi_n); // 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); obj->spi->DLY = 2; // 2 SPI clock times pre-delay // enable the ssp channel ssp_enable(obj); } void spi_free(spi_t *obj) { } void spi_format(spi_t *obj, int bits, int mode, int slave) { MBED_ASSERT(((bits >= 1) && (bits <= 16)) && ((mode >= 0) && (mode <= 3))); ssp_disable(obj); obj->spi->CFG &= ~((0x3 << 4) | (1 << 2)); obj->spi->CFG |= ((mode & 0x3) << 4) | ((slave ? 0 : 1) << 2); obj->spi->TXDATCTL &= ~( 0xF << 24); obj->spi->TXDATCTL |= (((bits & 0xF) - 1) << 24); ssp_enable(obj); } void spi_frequency(spi_t *obj, int hz) { ssp_disable(obj); // rise DIV value if it cannot be divided obj->spi->DIV = (SystemCoreClock + (hz - 1))/hz - 1; ssp_enable(obj); } static inline int ssp_disable(spi_t *obj) { return obj->spi->CFG &= ~(1 << 0); } static inline int ssp_enable(spi_t *obj) { return obj->spi->CFG |= (1 << 0); } static inline int ssp_readable(spi_t *obj) { return obj->spi->STAT & (1 << 0); } static inline int ssp_writeable(spi_t *obj) { return obj->spi->STAT & (1 << 1); } static inline void ssp_write(spi_t *obj, int value) { while (!ssp_writeable(obj)); // end of transfer obj->spi->TXDATCTL |= (1 << 20); obj->spi->TXDAT = value; } static inline int ssp_read(spi_t *obj) { while (!ssp_readable(obj)); return obj->spi->RXDAT; } static inline int ssp_busy(spi_t *obj) { // checking RXOV(Receiver Overrun interrupt flag) return obj->spi->STAT & (1 << 2); } 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->RXDAT; } void spi_slave_write(spi_t *obj, int value) { while (ssp_writeable(obj) == 0); obj->spi->TXDAT = value; } int spi_busy(spi_t *obj) { return ssp_busy(obj); } #endif