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/* @file spi.c
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* @brief
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* SPI module
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* @bug broken
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*/
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#include <avr/interrupt.h> |
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#include "ring_buffer.h" |
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#include "spi.h" |
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#include <dragonfly_lib.h> |
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/*
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SS = PB0
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SCK = PB1
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MOSI = PB2
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MISO = PB3
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*/
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/* Controls clock freq. see Table 72 of specs*/
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#define DOUBLE_SCK 1 |
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#define SPR0_BIT 1 |
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#define SPR1_BIT 0 |
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#define LSB 1 |
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#define MSB 0 |
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RING_BUFFER_NEW(spi_buffer, 16, char, spi_send_buff, spi_rec_buff); |
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volatile char spi_status; |
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char spi_mode;
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static spi_fun_recv_t spi_recv_function;
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//static spi_fun_send_t spi_send_function;
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void spi_init(char mode, spi_fun_recv_t recv_func) { |
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usb_puts("spi_init: start\n");
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spi_mode = mode; |
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//cli();
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RING_BUFFER_CLEAR(spi_send_buff); |
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RING_BUFFER_CLEAR(spi_rec_buff); |
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spi_recv_function = recv_func; |
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//spi_send_function = send_func;
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/* Enables the SPI module
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* Enable Interrupt, Enable SPI Module, LSB First, Master Mode, Clock div = 64
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*/
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SPCR = 0x00;
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SPCR = _BV(SPIE) | _BV(SPE) | _BV(DORD) | _BV(MSTR)| _BV(SPR1) | _BV(SPR0); |
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SPSR = 0x00;
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SPSR = _BV(SPI2X); |
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spi_status = SPI_VOID; |
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/* Set SCLK, SS, MOSI as outputs. MISO as input */
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if(mode == MASTER) {
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DDRB |= MOSI | SCLK | SS; |
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DDRB &= ~MISO; |
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PORTB |= SS; //Keep SS High until transmit
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/* Set SCLK, SS, MOSI as inputs. MISO as output */
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} else {
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DDRB &= ~MOSI & ~SCLK & ~SS; |
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DDRB |= MISO; |
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} |
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//sei();
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usb_puts("spi_init: end\n");
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} |
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int spi_send(char *data, size_t bytes) { |
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int i;
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usb_puts("spi_send: start\n");
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if(bytes == 0) |
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return -1; /* ...needed?*/ |
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//Prevent race condition on the buffer
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cli(); |
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for(i = 1; i < bytes; i++) { |
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// Fail if the buffer is full
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if(RING_BUFFER_FULL(spi_send_buff)) {
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sei(); |
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return -1; |
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} |
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RING_BUFFER_ADD(spi_send_buff, data[i]); |
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} |
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sei(); |
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spi_status = SPI_SENDING; |
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if (spi_mode == MASTER ){
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PORTB &= ~SS; //Select slave
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} |
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SPDR = *data; |
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usb_puts("spi_send: end\n");
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//sei();
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return 1; |
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} |
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void spi_master_recv_on() {
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spi_status = SPI_VOID; |
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PORTB &= ~SS; |
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} |
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void spi_master_recv_off() {
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spi_status = SPI_VOID; |
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PORTB |= SS; |
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} |
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ISR(SIG_SPI) { |
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usb_puts("ISR: start\n\r");
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char c;
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//usb_putc('['); usb_puti(c);usb_putc(',');usb_puti(spi_status);usb_puts("]\n\r");
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switch(spi_status){
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case SPI_SENDING:
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if(!RING_BUFFER_EMPTY(spi_send_buff)) {
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RING_BUFFER_REMOVE(spi_send_buff, c); |
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//usb_puts("SPDR=["); usb_puti(c);usb_putc(',');usb_puti(spi_status);usb_puts("]\n\r");
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SPDR = c; |
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//c = SPDR;
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//usb_puts("c=["); usb_puti(c);usb_putc(',');usb_puti(spi_status);usb_puts("]\n");
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} else {
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if (spi_mode == MASTER)
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PORTB |= SS; //Turn off Slave select
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spi_status = SPI_VOID; |
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} |
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break;
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case SPI_VOID:
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spi_recv_function(SPDR); |
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break;
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} |
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usb_puts("ISR: end\n");
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} |