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[/] [hf-risc/] [trunk/] [software/] [lib/] [spi.c] - Blame information for rev 17

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Line No. Rev Author Line
1 13 serginhofr 
/* file:          spi.c
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 * description:   low level SPI driver
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 * date:          09/2015
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 * author:        Sergio Johann Filho <sergio.filho@pucrs.br>
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 */
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#include <hf-risc.h>
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/* SPI mode: 0 ~ 3 */
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#define SPI_MODE        0
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/* SPI interface - EXTIO_OUT pins 0 (chip select), 1 (clock), 2 (master output) and 3 (chip select 2) */
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#define SPI_CS          0x01
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#define SPI_SCK         0x02
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#define SPI_MOSI        0x04
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#define SPI_CS2         0x08
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/* SPI interface - EXIO_IN pin 3 (master input) */
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#define SPI_MISO        0x08
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void spi_setup(void){
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// setup IO pins ...
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        EXTIO_OUT |= SPI_CS | SPI_CS2;
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#if SPI_MODE == 0 || SPI_MODE == 1
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        EXTIO_OUT &= ~SPI_SCK;
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#else
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        EXTIO_OUT |= SPI_SCK;
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#endif
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}
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void spi_start(void){
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// set CS low
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        EXTIO_OUT &= ~SPI_CS;
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}
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void spi_stop(void){
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// set CS high
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        EXTIO_OUT |= SPI_CS;
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}
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void spi_start2(void){
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// set CS low
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        EXTIO_OUT &= ~SPI_CS2;
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}
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void spi_stop2(void){
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// set CS high
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        EXTIO_OUT |= SPI_CS2;
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}
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int8_t spi_sendrecv(int8_t data){
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        int32_t i;
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        int8_t newdata = 0;
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#if SPI_MODE == 0
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        for (i = 0; i < 8; i++){
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                if (data & 0x80){
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                        EXTIO_OUT |= SPI_MOSI;
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                }else{
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                        EXTIO_OUT &= ~SPI_MOSI;
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                }
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                data <<= 1;
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                EXTIO_OUT |= SPI_SCK;
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                newdata <<= 1;
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                newdata |= ((EXTIO_IN & SPI_MISO) ? 1 : 0);
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                EXTIO_OUT &= ~SPI_SCK;
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        }
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        return newdata;
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#endif
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#if SPI_MODE == 1
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        for (i = 0; i < 8; i++){
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                EXTIO_OUT |= SPI_SCK;
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                if (data & 0x80){
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                        EXTIO_OUT |= SPI_MOSI;
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                }else{
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                        EXTIO_OUT &= ~SPI_MOSI;
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                }
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                data <<= 1;
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                EXTIO_OUT &= ~SPI_SCK;
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                newdata <<= 1;
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                newdata |= ((EXTIO_IN & SPI_MISO) ? 1 : 0);
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        }
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        return newdata;
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#endif
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#if SPI_MODE == 2
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        for (i = 0; i < 8; i++){
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                if (data & 0x80){
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                        EXTIO_OUT |= SPI_MOSI;
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                }else{
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                        EXTIO_OUT &= ~SPI_MOSI;
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                }
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                data <<= 1;
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                EXTIO_OUT &= ~SPI_SCK;
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                newdata <<= 1;
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                newdata |= ((EXTIO_IN & SPI_MISO) ? 1 : 0);
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                EXTIO_OUT |= SPI_SCK;
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        }
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        return newdata;
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#endif
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#if SPI_MODE == 3
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        for (i = 0; i < 8; i++){
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                EXTIO_OUT &= ~SPI_SCK;
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                if (data & 0x80){
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                        EXTIO_OUT |= SPI_MOSI;
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                }else{
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                        EXTIO_OUT &= ~SPI_MOSI;
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                }
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                data <<= 1;
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                EXTIO_OUT |= SPI_SCK;
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                newdata <<= 1;
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                newdata |= ((EXTIO_IN & SPI_MISO) ? 1 : 0);
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        }
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        return newdata;
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#endif
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}
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