1 /* mbed Microcontroller Library
2 * Copyright (c) 2006-2013 ARM Limited
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
16 #include "mbed_assert.h"
21 #include "mbed_error.h"
25 static const SWM_Map SWM_SPI_SSEL[] = {
30 static const SWM_Map SWM_SPI_SCLK[] = {
35 static const SWM_Map SWM_SPI_MOSI[] = {
40 static const SWM_Map SWM_SPI_MISO[] = {
45 // bit flags for used SPIs
46 static unsigned char spi_used = 0;
48 static int get_available_spi(void)
52 if ((spi_used & (1 << i)) == 0)
58 static inline void spi_disable(spi_t *obj);
59 static inline void spi_enable(spi_t *obj);
61 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel)
63 int spi_n = get_available_spi();
65 error("No available SPI");
68 spi_used |= (1 << spi_n);
70 obj->spi = (spi_n) ? (LPC_SPI0_Type *)(LPC_SPI1_BASE) : (LPC_SPI0_Type *)(LPC_SPI0_BASE);
75 if (sclk != (PinName)NC) {
76 swm = &SWM_SPI_SCLK[obj->spi_n];
77 regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
78 LPC_SWM->PINASSIGN[swm->n] = regVal | ((sclk >> PIN_SHIFT) << swm->offset);
81 if (mosi != (PinName)NC) {
82 swm = &SWM_SPI_MOSI[obj->spi_n];
83 regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
84 LPC_SWM->PINASSIGN[swm->n] = regVal | ((mosi >> PIN_SHIFT) << swm->offset);
87 if (miso != (PinName)NC) {
88 swm = &SWM_SPI_MISO[obj->spi_n];
89 regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
90 LPC_SWM->PINASSIGN[swm->n] = regVal | ((miso >> PIN_SHIFT) << swm->offset);
93 if (ssel != (PinName)NC) {
94 swm = &SWM_SPI_SSEL[obj->spi_n];
95 regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
96 LPC_SWM->PINASSIGN[swm->n] = regVal | ((ssel >> PIN_SHIFT) << swm->offset);
100 obj->spi->INTENCLR = 0x3f;
102 LPC_SYSCON->SYSAHBCLKCTRL |= (1 << (11 + obj->spi_n));
103 LPC_SYSCON->PRESETCTRL &= ~(1 << obj->spi_n);
104 LPC_SYSCON->PRESETCTRL |= (1 << obj->spi_n);
106 // set default format and frequency
107 if (ssel == (PinName)NC) {
108 spi_format(obj, 8, 0, 0); // 8 bits, mode 0, master
110 spi_format(obj, 8, 0, 1); // 8 bits, mode 0, slave
112 spi_frequency(obj, 1000000);
113 obj->spi->DLY = 2; // 2 SPI clock times pre-delay
115 // enable the ssp channel
119 void spi_free(spi_t *obj)
123 void spi_format(spi_t *obj, int bits, int mode, int slave)
125 MBED_ASSERT(((bits >= 1) && (bits <= 16)) && ((mode >= 0) && (mode <= 3)));
128 obj->spi->CFG &= ~((0x3 << 4) | (1 << 2));
129 obj->spi->CFG |= ((mode & 0x3) << 4) | ((slave ? 0 : 1) << 2);
131 obj->spi->TXCTL &= ~( 0xF << 24);
132 obj->spi->TXCTL |= ((bits - 1) << 24);
137 void spi_frequency(spi_t *obj, int hz)
141 // rise DIV value if it cannot be divided
142 obj->spi->DIV = (SystemCoreClock + (hz - 1))/hz - 1;
147 static inline void spi_disable(spi_t *obj)
149 obj->spi->CFG &= ~(1 << 0);
152 static inline void spi_enable(spi_t *obj)
154 obj->spi->CFG |= (1 << 0);
157 static inline int spi_readable(spi_t *obj)
159 return obj->spi->STAT & (1 << 0);
162 static inline int spi_writeable(spi_t *obj)
164 return obj->spi->STAT & (1 << 1);
167 static inline void spi_write(spi_t *obj, int value)
169 while (!spi_writeable(obj));
171 obj->spi->TXCTL |= (1 << 20);
172 obj->spi->TXDAT = (value & 0xffff);
175 static inline int spi_read(spi_t *obj)
177 while (!spi_readable(obj));
178 return (obj->spi->RXDAT & 0xFFFF);
181 int spi_master_write(spi_t *obj, int value)
183 spi_write(obj, value);
184 return spi_read(obj);
187 int spi_busy(spi_t *obj)
189 // checking RXOV(Receiver Overrun interrupt flag)
190 return obj->spi->STAT & (1 << 2);
193 int spi_slave_receive(spi_t *obj)
195 return (spi_readable(obj) && !spi_busy(obj)) ? (1) : (0);
198 int spi_slave_read(spi_t *obj)
200 return (obj->spi->RXDAT & 0xFFFF);
203 void spi_slave_write(spi_t *obj, int value)
205 while (spi_writeable(obj) == 0);
206 obj->spi->TXDAT = value;