mbed library sources
Dependents: frdm_kl05z_gpio_test
Fork of mbed-src by
Diff: targets/hal/TARGET_Freescale/TARGET_K20D5M/spi_api.c
- Revision:
- 195:442092318da6
- Parent:
- 73:299c67215126
- Child:
- 227:7bd0639b8911
--- a/targets/hal/TARGET_Freescale/TARGET_K20D5M/spi_api.c Fri May 16 16:15:06 2014 +0100 +++ b/targets/hal/TARGET_Freescale/TARGET_K20D5M/spi_api.c Mon May 19 08:15:19 2014 +0100 @@ -54,7 +54,7 @@ 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_Type*)pinmap_merge(spi_data, spi_cntl); if ((int)obj->spi == NC) { error("SPI pinout mapping failed"); @@ -63,9 +63,8 @@ SIM->SCGC5 |= SIM_SCGC5_PORTC_MASK | SIM_SCGC5_PORTD_MASK; SIM->SCGC6 |= SIM_SCGC6_SPI0_MASK; - // halted state - obj->spi->MCR &= ~SPI_MCR_MDIS_MASK; - obj->spi->MCR |= SPI_MCR_HALT_MASK | SPI_MCR_DIS_RXF_MASK | SPI_MCR_DIS_TXF_MASK; + obj->spi->MCR &= ~(SPI_MCR_MDIS_MASK | SPI_MCR_HALT_MASK); + //obj->spi->MCR |= SPI_MCR_DIS_RXF_MASK | SPI_MCR_DIS_TXF_MASK; // set default format and frequency if (ssel == NC) { @@ -77,8 +76,6 @@ // not halt in the debug mode obj->spi->SR |= SPI_SR_EOQF_MASK; - // enable SPI - obj->spi->MCR &= (~SPI_MCR_HALT_MASK); // pin out the spi pins pinmap_pinout(mosi, PinMap_SPI_MOSI); @@ -93,9 +90,9 @@ // [TODO] } void spi_format(spi_t *obj, int bits, int mode, int slave) { - if ((bits != 8) && (bits != 16)) { - error("Only 8/16 bits SPI supported"); - } + if ((bits < 4) || (bits > 16)) + error("SPI: Only frames between 4 and 16-bit supported"); + if ((mode < 0) || (mode > 3)) { error("SPI mode unsupported"); @@ -109,48 +106,45 @@ obj->spi->MCR |= ((!slave) << SPI_MCR_MSTR_SHIFT); // CTAR0 is used - obj->spi->CTAR[0] &= ~(SPI_CTAR_CPHA_MASK | SPI_CTAR_CPOL_MASK); - obj->spi->CTAR[0] |= (polarity << SPI_CTAR_CPOL_SHIFT) | (phase << SPI_CTAR_CPHA_SHIFT); + obj->spi->CTAR[0] &= ~(SPI_CTAR_CPHA_MASK | SPI_CTAR_CPOL_MASK | SPI_CTAR_FMSZ_MASK); + obj->spi->CTAR[0] |= (polarity << SPI_CTAR_CPOL_SHIFT) | (phase << SPI_CTAR_CPHA_SHIFT) | ((bits - 1) << SPI_CTAR_FMSZ_SHIFT); } static const uint8_t baudrate_prescaler[] = {2,3,5,7}; -static const uint32_t baudrate_scaler[] = {2, 4, 6, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768}; -static const uint8_t delay_prescaler[] = {1, 3, 5, 7}; +static const uint16_t baudrate_scaler[] = {2,4,6,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768}; void spi_frequency(spi_t *obj, int hz) { - uint32_t error = 0; + uint32_t f_error = 0; uint32_t p_error = 0xffffffff; uint32_t ref = 0; uint32_t br = 0; uint32_t ref_spr = 0; uint32_t ref_prescaler = 0; + uint32_t ref_dr = 0; // bus clk uint32_t PCLK = bus_frequency(); - uint32_t divisor = 2; - uint32_t prescaler; - /* TODO */ for (uint32_t i = 0; i < 4; i++) { - prescaler = baudrate_prescaler[i]; - divisor = 2; - for (br = 0; br <= 15; br++, divisor *= 2) { + for (br = 0; br <= 15; br++) { for (uint32_t dr = 0; dr < 2; dr++) { - ref = (PCLK / prescaler) * ((1U + dr) / divisor); + ref = (PCLK * (1U + dr) / baudrate_prescaler[i]) / baudrate_scaler[br]; if (ref > (uint32_t)hz) continue; - error = hz - ref; - if (error < p_error) { + f_error = hz - ref; + if (f_error < p_error) { ref_spr = br; ref_prescaler = i; - p_error = error; + ref_dr = dr; + p_error = f_error; } } } } // set PBR and BR - obj->spi->CTAR[0] = ((ref_prescaler & 0x3) << SPI_CTAR_PBR_SHIFT) | (ref_spr & 0xf); + obj->spi->CTAR[0] &= ~(SPI_CTAR_PBR_MASK | SPI_CTAR_BR_MASK | SPI_CTAR_DBR_MASK); + obj->spi->CTAR[0] |= (ref_prescaler << SPI_CTAR_PBR_SHIFT) | (ref_spr << SPI_CTAR_BR_SHIFT) | (ref_dr << SPI_CTAR_DBR_SHIFT); } static inline int spi_writeable(spi_t *obj) { @@ -158,15 +152,15 @@ } static inline int spi_readable(spi_t *obj) { - return (obj->spi->SR & SPI_SR_RFDF_MASK) ? 0 : 1; + return (obj->spi->SR & SPI_SR_RFDF_MASK) ? 1 : 0; } int spi_master_write(spi_t *obj, int value) { + //clear RX buffer flag + obj->spi->SR |= SPI_SR_RFDF_MASK; // wait tx buffer empty while(!spi_writeable(obj)); - obj->spi->PUSHR = SPI_PUSHR_TXDATA(value & 0xff) /*| SPI_PUSHR_EOQ_MASK*/; - - while (!obj->spi->SR & SPI_SR_TCF_MASK); // wait for transfer to be complete + obj->spi->PUSHR = SPI_PUSHR_TXDATA(value & 0xffff) /*| SPI_PUSHR_EOQ_MASK*/; // wait rx buffer full while (!spi_readable(obj));