Revision 731
code commented and cleaned up. should work but untested.
| branches/encoders/code/projects/libdragonfly/spi.c | ||
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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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/** |
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* @file spi.c |
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* @brief Basic SPI module to handle encoders |
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* @author Colony Project, CMU Robotics Club |
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* @bug Not tested |
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* Need to move spi.h include into dragonfly_lib.h when stable |
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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 <dragonfly_lib.h>
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#include "spi.h" |
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#include <dragonfly_lib.h> |
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static volatile char spi_bytes; /* number of bytes to read */ |
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static spi_fun_recv_t spi_recv_func; /* byte handler */ |
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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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void spi_init (spi_fun_recv_t recv_func) |
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{
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/* Enable Interrupt, Enable SPI Module, MSB First, Master Mode, Clock div = 64 */ |
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SPCR = _BV(SPE) | _BV(SPIE) | _BV(DORD) | _BV(MSTR) | _BV(SPR1) | _BV(SPR0); |
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SPSR = _BV(SPI2X); |
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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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#define FIRST_BYTE 1 |
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#define SECOND_BYTE 2 |
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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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volatile 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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static volatile uint16_t i; |
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void spi_init(spi_fun_recv_t recv_func) {
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usb_puts("spi_init: start\n");
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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 = _BV(SPE) | _BV(SPIE)|_BV(DORD) | _BV(MSTR)| _BV(SPR1) | _BV(SPR0); |
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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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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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DDRB = MOSI | SCLK | SS; |
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DDRB &= ~MISO; |
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/* Keep SS high until transmit */ |
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PORTB |= SS; |
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//sei(); |
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usb_puts("spi_init: end\n");
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/* set function to be executed when we receive a byte */ |
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spi_recv_func = recv_func; |
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spi_bytes = 0; |
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} |
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void spi_transfer(char c){
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spi_mode = FIRST_BYTE; |
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PORTB &= ~SS; |
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SPDR = c; |
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/* Transfer a given byte to slave and receive a byte */ |
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void spi_transfer(char bytes) |
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{
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spi_bytes = bytes; |
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PORTB &= ~SS; /* Set SS low to initiate transmission */ |
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SPDR = 0xff; /* Initiate data transmision */ |
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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=SPDR; |
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//PORTB |= SS; |
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usb_puts("spi_mode is: "); usb_puti(spi_mode);usb_puts("\r\n");
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if(spi_mode < 4){
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i=0; |
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i = (uint16_t)SPDR; |
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spi_recv_function(SPDR); |
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SPDR = 0xff; |
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spi_mode++; |
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//usb_puts("done\n\r");
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} else {
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spi_recv_function(SPDR); |
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//usb_puts("second byte\r\n");
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i |= (uint16_t)SPDR << 8; |
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spi_mode = 1; |
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PORTB |= SS; |
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usb_puts("\r\n");
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} |
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//usb_puts("ISR: end\n");
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ISR(SIG_SPI) |
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{
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/* only handle intterupt when we are expecting data */ |
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if(spi_bytes > 0){
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/* process byte */ |
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spi_recv_func(SPDR); |
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/* if we've read all the bytes, set SS high to end transmission, |
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* otherwise get the next byte */ |
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if(--spi_bytes == 0) |
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PORTB |= SS; |
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else |
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SPDR = 0xff; |
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} |
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} |
| branches/encoders/code/projects/libdragonfly/spi.h | ||
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/** |
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* @file spi.h |
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* @brief Definitions for SPI |
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* @author Colony Project, CMU Robotics Club |
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**/ |
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#ifndef __SPI_H__ |
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#define __SPI_H__ |
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#define DOUBLE_SCK 1 |
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#define SPR0_BIT 1 |
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#define LSB 1 |
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#define MSB 0 |
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#define MASTER 1 |
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#define SLAVE 0 |
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#define SPI_SENDING 1 |
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#define SPI_VOID 0 |
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#define SPI_MASTER_RECV 2 |
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/* Pin Defines */ |
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#define MOSI _BV(PB2) |
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#define MISO _BV(PB3) |
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#define SS _BV(PB0) |
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#define SS _BV(PB0)
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#define SCLK _BV(PB1) |
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#define size_t int |
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typedef void (*spi_fun_recv_t)(unsigned char); |
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typedef void (*spi_fun_send_t)(unsigned char); |
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void spi_init(spi_fun_recv_t recv_func); |
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int spi_send(char *data, size_t bytes); |
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void spi_master_recv_on(void); |
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void spi_master_recv_off(void); |
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void spi_transfer(char c); |
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typedef void (*spi_fun_recv_t)(char); |
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void spi_init (spi_fun_recv_t); |
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void spi_transfer (char); |
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#endif |
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