mbed library sources
Dependents: frdm_kl05z_gpio_test
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Diff: targets/hal/TARGET_STM/TARGET_STM32F4XX/spi_api.c
- Revision:
- 20:4263a77256ae
- Child:
- 227:7bd0639b8911
diff -r 398f4c622e1b -r 4263a77256ae targets/hal/TARGET_STM/TARGET_STM32F4XX/spi_api.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/hal/TARGET_STM/TARGET_STM32F4XX/spi_api.c Tue Sep 10 15:14:19 2013 +0300 @@ -0,0 +1,235 @@ +/* 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 "spi_api.h" + +#if DEVICE_SPI +#include <math.h> + +#include "cmsis.h" +#include "pinmap.h" +#include "error.h" + +static const PinMap PinMap_SPI_SCLK[] = { + {PA_5, SPI_1, STM_PIN_DATA(2, 5)}, + {PB_3, SPI_1, STM_PIN_DATA(2, 5)}, + {PB_3, SPI_3, STM_PIN_DATA(2, 6)}, + {PB_10, SPI_2, STM_PIN_DATA(2, 5)}, + {PB_13, SPI_2, STM_PIN_DATA(2, 5)}, + {PC_10, SPI_3, STM_PIN_DATA(2, 6)}, + {NC, NC, 0} +}; + +static const PinMap PinMap_SPI_MOSI[] = { + {PA_7, SPI_1, STM_PIN_DATA(2, 5)}, + {PB_5, SPI_1, STM_PIN_DATA(2, 5)}, + {PB_5, SPI_3, STM_PIN_DATA(2, 6)}, + {PB_15, SPI_2, STM_PIN_DATA(2, 5)}, + {PC_3, SPI_2, STM_PIN_DATA(2, 5)}, + {PC_12, SPI_3, STM_PIN_DATA(2, 6)}, + {NC, NC, 0} +}; + +static const PinMap PinMap_SPI_MISO[] = { + {PA_6, SPI_1, STM_PIN_DATA(2, 5)}, + {PB_4, SPI_1, STM_PIN_DATA(2, 5)}, + {PB_4, SPI_3, STM_PIN_DATA(2, 6)}, + {PB_14, SPI_2, STM_PIN_DATA(2, 5)}, + {PC_2, SPI_2, STM_PIN_DATA(2, 5)}, + {PC_11, SPI_3, STM_PIN_DATA(2, 6)}, + {NC, NC, 0} +}; + +static const PinMap PinMap_SPI_SSEL[] = { + {PA_4, SPI_1, STM_PIN_DATA(2, 5)}, + {PA_4, SPI_3, STM_PIN_DATA(2, 6)}, + {PA_15, SPI_1, STM_PIN_DATA(2, 5)}, + {PA_15, SPI_3, STM_PIN_DATA(2, 6)}, + {PB_9, SPI_2, STM_PIN_DATA(2, 5)}, + {PB_12, SPI_2, STM_PIN_DATA(2, 5)}, + {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 = (SPI_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_1: + RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN | RCC_AHB1ENR_GPIOBEN; + RCC->APB2ENR |= RCC_APB2ENR_SPI1EN; + break; + case SPI_2: + RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN | RCC_AHB1ENR_GPIOCEN; + RCC->APB1ENR |= RCC_APB1ENR_SPI2EN; + break; + case SPI_3: + RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN | RCC_AHB1ENR_GPIOCEN; + RCC->APB1ENR |= RCC_APB1ENR_SPI3EN; + 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); + } + else { + // Use software slave management + obj->spi->CR1 |= SPI_CR1_SSM | SPI_CR1_SSI; + } +} + +void spi_free(spi_t *obj) {} + +void spi_format(spi_t *obj, int bits, int mode, int slave) { + ssp_disable(obj); + + if (!(bits == 8 || bits == 16) || !(mode >= 0 && mode <= 3)) { + error("SPI format error"); + } + + + int polarity = (mode & 0x2) ? 1 : 0; + int phase = (mode & 0x1) ? 1 : 0; + + obj->spi->CR1 &= ~0x807; + obj->spi->CR1 |= ((phase) ? 1 : 0) << 0 | + ((polarity) ? 1 : 0) << 1 | + ((slave) ? 0: 1) << 2 | + ((bits == 16) ? 1 : 0) << 11; + + if (obj->spi->SR & SPI_SR_MODF) { + obj->spi->CR1 = obj->spi->CR1; + } + + ssp_enable(obj); +} + +void spi_frequency(spi_t *obj, int hz) { + ssp_disable(obj); + + // SPI1 runs from PCLK2, which runs at SystemCoreClock / 2. SPI2 and SPI3 + // run from PCLK1, which runs at SystemCoreClock / 4. + uint32_t PCLK = SystemCoreClock; + switch ((int)obj->spi) { + case SPI_1: PCLK = PCLK >> 1; break; + case SPI_2: PCLK = PCLK >> 2; break; + case SPI_3: PCLK = PCLK >> 2; break; + } + + // Choose the baud rate divisor (between 2 and 256) + uint32_t divisor = PCLK / hz; + + // Find the nearest power-of-2 + divisor = divisor > 0 ? divisor-1 : 0; + divisor |= divisor >> 1; + divisor |= divisor >> 2; + divisor |= divisor >> 4; + divisor |= divisor >> 8; + divisor |= divisor >> 16; + divisor++; + + uint32_t baud_rate = __builtin_ffs(divisor) - 1; + baud_rate = baud_rate > 0x7 ? 0x7 : baud_rate; + + obj->spi->CR1 &= ~(0x7 << 3); + obj->spi->CR1 |= baud_rate << 3; + + ssp_enable(obj); +} + +static inline int ssp_disable(spi_t *obj) { + // TODO: Follow the instructions in 25.3.8 for safely disabling the SPI + return obj->spi->CR1 &= ~SPI_CR1_SPE; +} + +static inline int ssp_enable(spi_t *obj) { + return obj->spi->CR1 |= SPI_CR1_SPE; +} + +static inline int ssp_readable(spi_t *obj) { + return obj->spi->SR & SPI_SR_RXNE; +} + +static inline int ssp_writeable(spi_t *obj) { + return obj->spi->SR & SPI_SR_TXE; +} + +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 & SPI_SR_BSY) ? (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); +} + +#endif