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mcp2515.c
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/*
* This file is part of the HCAN tools suite.
*
* HCAN is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* HCAN is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with HCAN; if not, write to the Free Software Foundation, Inc., 51
* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* (c) 2006 by Martin Haller, mah (at) iuse (dot) org
*
*
* Parts of this code are adapted from Florian Greif's MCP2515 Code; he
* released it under the GPL:
* http://www.kreatives-chaos.com/index.php?seite=mcp2515_init
*
*
* Parts of this code are adapted from Martin Thomas' MCP2515 Code:
*
*****************************************************************************
*
* Controller Area Network (CAN) Demo-Application
* Atmel AVR with Microchip MCP2515
*
* Copyright (C) 2005 Martin THOMAS, Kaiserslautern, Germany
* <eversmith@heizung-thomas.de>
* http://www.siwawi.arubi.uni-kl.de/avr_projects
*
*****************************************************************************
*
* File : mcp2515.c
* Version : 0.9
*
* Summary : MCP2515 "low-level" driver
*
* Parts of this code are adapted from a MCP2510 sample-application
* by KVASER AB, http://www.kvaser.com (KVASER-code is marked as free)
*
* This code-module is free to use but you have to keep the copyright
* notice.
*
*/
#include <avr/io.h>
#include <avr/interrupt.h>
////#include <avr/signal.h>
#include <avr/wdt.h>
#include "mcp2515.h"
#include "mcp2515_defs.h"
#include "canix.h"
#include "tools.h"
#define MCP2515_OK (0)
#define MCP2515_FAIL (1)
void spi_init(void)
{
// Aktivieren der SCK, MISO und MOSI Ports
// Die CS Ports (ChipSelect) werden von den can_open_interface
// Aufrufen initialisiert
SPI_PORT_DDR |= (1<<SPI_SCK)|(1<<SPI_MOSI);
SPI_PORT &= ~(1<<SPI_SCK)|(1<<SPI_MOSI)|(1<<SPI_MISO);
// SPI Masterinterface aktivieren
// f(spi) = f(cpu) / 2 (Double-Speed, da wir Master sind)
SPCR = (1<<SPE)|(1<<MSTR);
SPSR = (1<<SPI2X);
}
uint8_t spi_putc( uint8_t data )
{
/* Sendet ein Byte */
SPDR = data;
/* Wartet bis Byte gesendet wurde */
while( !( SPSR & (1<<SPIF) ) )
;
return SPDR;
}
uint8_t spi_getc(void)
{
return spi_putc(0);
}
void can_enable_mcp2515(void)
{
SPI_CS_PORT &= ~(1<< SPI_CS);
}
void can_disable_mcp2515(void)
{
SPI_CS_PORT |= (1<< SPI_CS);
}
void mcp2515_bit_modify(uint8_t adress, uint8_t mask, uint8_t data)
{
can_enable_mcp2515();
spi_putc(SPI_BIT_MODIFY);
spi_putc(adress);
spi_putc(mask);
spi_putc(data);
can_disable_mcp2515();
}
uint8_t mcp2515_read_register(const uint8_t address)
{
uint8_t ret;
can_enable_mcp2515();
spi_putc(SPI_READ);
spi_putc(address);
ret = spi_getc();
can_disable_mcp2515();
return ret;
}
void mcp2515_write_register(uint8_t adress, uint8_t data )
{
can_enable_mcp2515();
spi_putc(SPI_WRITE);
spi_putc(adress);
spi_putc(data);
can_disable_mcp2515();
}
uint8_t mcp2515_set_mode(uint8_t mode)
{
uint8_t i;
mcp2515_bit_modify( MCP_CANCTRL, MODE_MASK, mode);
// verify as advised in datasheet
i = mcp2515_read_register( MCP_CANCTRL);
i &= MODE_MASK;
if ( i == mode )
return MCP2515_OK;
else
{
return MCP2515_FAIL;
}
}
void mcp2515_write_register_p(uint8_t adress, const uint8_t *data,
uint8_t length )
{
uint8_t i;
can_enable_mcp2515();
spi_putc(SPI_WRITE);
spi_putc(adress);
for (i=0; i<length ;i++ )
spi_putc(*data++);
can_disable_mcp2515();
}
void mcp2515_read_register_p(uint8_t adress, uint8_t *data, uint8_t length )
{
uint8_t i;
can_enable_mcp2515();
spi_putc(SPI_READ);
spi_putc(adress);
for (i=0; i<length ;i++ )
*data++ = spi_putc(0xff);
can_disable_mcp2515();
}
uint8_t can_open_interface(void)
{
uint8_t res;
// 1. Aktivieren des CS Pins
SPI_CS_PORT_DDR |= (1<< SPI_CS);
SPI_CS_PORT |= (1<< SPI_CS);
// 2. MCP2515 Software Reset
can_enable_mcp2515();
spi_putc(SPI_RESET);
can_disable_mcp2515();
delay(255);
// Device in den Konfigurations Modus versetzten
res = mcp2515_set_mode( MODE_CONFIG);
if (res)
return res;
// Speed einstellen:
// BRP = F_CAN / (CAN_SPEED*2*8)) - 1
//
// d.h. fuer
// F_CAN = 8MHz:
// - CAN_SPEED: 125 KHz: BRP = 3
// - CAN_SPEED: 250 KHz: BRP = 1
// - CAN_SPEED: 500 KHz: BRP = 0
//
//mcp2515_write_register( CNF1, (1<<BRP0)|(1<<BRP1)|(1<<BRP2));
mcp2515_write_register( CNF1, (F_CAN / (CAN_SPEED*2*8)) - 1);
// Prop Seg und Phase Seg1 einstellen
mcp2515_write_register( CNF2, (1<<BTLMODE)|(1<<PHSEG11) );
// Wake-up Filter deaktivieren, Phase Seg2 einstelen
mcp2515_write_register( CNF3, (1<<PHSEG21) );
// Aktivieren der Rx Buffer Interrupts
mcp2515_write_register( CANINTE, /*(1<<RX1IE)|(1<<RX0IE)*/ 0);
// Buffer 0 : Empfangen aller Nachrichten, kein Rollover (siehe unten)
mcp2515_write_register( RXB0CTRL, (1<<RXM1)|(1<<RXM0));
/* Buffer 1 : wird nicht verwendet, da der folgender Effekt aufgetreten
* ist: Wenn man Buffer 1 + Rollover (BUKT) aktiviert, dann kann es bei
* hoher Empfangsframerate passieren, dass der MCP kein Paket mehr
* meldet. Nach einem Reset geht es wieder. Effekt tritt auf, wenn man
* per HCAN Syslog einen ganzen Stoss an Frames sendet
*/
// Deaktivieren der Pins RXnBF Pins ( High Impedance State )
mcp2515_write_register( BFPCTRL, 0 );
// TXnRTS Bits als Inputs schalten
mcp2515_write_register( TXRTSCTRL, 0 );
// Zurueck in den Normal-Mode
res = mcp2515_set_mode( MODE_NORMAL);
if (res)
return res;
return 0;
}
uint8_t can_send_message(uint32_t id, const uint8_t *data, uint8_t length)
{
uint8_t tx_index;
uint8_t temp[4];
// Herausfinden, welcher Buffer frei ist:
if (can_sendable(0))
tx_index = 0;
else if (can_sendable(1))
tx_index = 1;
else if (can_sendable(2))
tx_index = 2;
else
{
canix_tx_dropped++;
return MCP2515_FAIL;
}
cli();
// Dieser Buffer frei, also hier einfuettern
//
// Identifier einstellen
temp[0] = (uint8_t) (id>>21);
temp[1] = (((uint8_t) (id>>16)) & 0x03) |
(((uint8_t) (id>>13)) & 0xE0) | (1<<EXIDE);
temp[2] = (uint8_t) (id>>8);
temp[3] = (uint8_t) id;
mcp2515_write_register_p( TXB0SIDH + (tx_index << 4), temp, 4 );
// Datenlaenge einstellen
mcp2515_write_register( TXB0DLC + (tx_index << 4), length );
// Datenbytes schreiben
mcp2515_write_register_p( TXB0D0 + (tx_index << 4), data, length );
// REQ Bit setzen
mcp2515_bit_modify(TXB0CTRL + (tx_index << 4), (1 << TXREQ), (1<<TXREQ));
// Nachricht senden
can_enable_mcp2515();
spi_putc(SPI_RTS | (1 << tx_index));
can_disable_mcp2515();
sei();
canix_tx_sent++;
return MCP2515_OK;
}
bool can_sendable(const uint8_t tx_index)
{
uint8_t v;
cli();
v = mcp2515_read_register( TXB0CTRL + (tx_index << 4) );
sei();
return (! (v & (1 << TXREQ)));
}
bool can_any_sendable(void)
{
return (can_sendable(0) || can_sendable(1) || can_sendable(2));
}
bool can_message_available(void)
{
uint8_t n;
cli();
n = canix_rxq_size() > 0;
sei();
return n;
}
bool mcp2515_message_available(void)
{
char temp;
temp = mcp2515_read_register(CANINTF);
return (temp & ((1 << RX0IF)));
}
// wird NUR vom ISR aufgerufen!! (Daher kein cli()/sei() Paerchen)
uint8_t mcp2515_read_message(uint32_t *extended, char *data)
{
uint8_t size;
uint8_t id[4];
mcp2515_read_register_p( RXB0SIDH, id, 4 );
*extended = id[3] |
(((uint32_t) id[2]) << 8) |
(((uint32_t) id[1] & 0x03) << 16) |
(((uint32_t) id[1] & 0xe0) >> 3 << 16) |
(((uint32_t) id[0]) << 21);
// Frame Payload size
size = mcp2515_read_register( RXB0DLC) & 0x0F;
// Daten kopieren
mcp2515_read_register_p(RXB0D0, (uint8_t *)data, size);
// RX0 Interrupt Flag loeschen
mcp2515_bit_modify(CANINTF, 0x01, 0x00 );
return size;
}
uint8_t can_read_message(uint32_t *extended, char *data)
{
uint8_t size = 0;
uint8_t i;
cli();
if (canix_rxq_size())
{
uint8_t idx;
idx = canix_rxq_fetch_one();
*extended = canix_rx_queue[idx].extended;
for (i = 0; i < canix_rx_queue[idx].size; i++)
data[i] = canix_rx_queue[idx].data[i];
size = canix_rx_queue[idx].size;
canix_rx_queue[idx].used = 0;
}
sei();
return size;
}
uint16_t can_error_counters(void)
{
return (mcp2515_read_register(REC) << 8) |
mcp2515_read_register(TEC);
}