/*********************************************************************************************************
** Function name: mcp2515_initCANBuffers
** Descriptions: init canbuffers
*********************************************************************************************************/
void MCP_CAN::mcp2515_initCANBuffers(void)
{
INT8U i, a1, a2, a3;
INT8U std = 0;
INT8U ext = 1;
INT32U ulMask = 0x00, ulFilt = 0x00;
mcp2515_write_id(MCP_RXM0SIDH, ext, ulMask); /*Set both masks to 0 */
mcp2515_write_id(MCP_RXM1SIDH, ext, ulMask); /*Mask register ignores ext bit */
/* Set all filters to 0 */
mcp2515_write_id(MCP_RXF0SIDH, ext, ulFilt); /* RXB0: extended */
mcp2515_write_id(MCP_RXF1SIDH, std, ulFilt); /* RXB1: standard */
mcp2515_write_id(MCP_RXF2SIDH, ext, ulFilt); /* RXB2: extended */
mcp2515_write_id(MCP_RXF3SIDH, std, ulFilt); /* RXB3: standard */
mcp2515_write_id(MCP_RXF4SIDH, ext, ulFilt);
mcp2515_write_id(MCP_RXF5SIDH, std, ulFilt);
/* Clear, deactivate the three */
/* transmit buffers */
/* TXBnCTRL -> TXBnD7 */
a1 = MCP_TXB0CTRL;
a2 = MCP_TXB1CTRL;
a3 = MCP_TXB2CTRL;
for (i = 0; i < 14; i++) { /* in-buffer loop */
mcp2515_setRegister(a1, 0);
mcp2515_setRegister(a2, 0);
mcp2515_setRegister(a3, 0);
a1++;
a2++;
a3++;
}
mcp2515_setRegister(MCP_RXB0CTRL, 0);
mcp2515_setRegister(MCP_RXB1CTRL, 0);
}
bool mcp2515_set_filter(uint8_t number, const can_filter_t *filter)
{
uint8_t mask_address = 0;
uint8_t mode = mcp2515_read_register(CANSTAT);
if (number > 5)
return false;
// change to configuration mode
mcp2515_change_operation_mode( (1<<REQOP2) );
// set filter mask
if (number == 0)
{
mask_address = RXM0SIDH;
#if SUPPORT_EXTENDED_CANID
if (filter->flags.extended == 0x3) {
// only extended identifier
mcp2515_write_register(RXB0CTRL, (1<<RXM1));
}
else if (filter->flags.extended == 0x2) {
// only standard identifier
mcp2515_write_register(RXB0CTRL, (1<<RXM0));
}
else {
// receive all messages
mcp2515_write_register(RXB0CTRL, 0);
}
#else
// Buffer 0: Empfangen aller Nachrichten mit Standard Identifier
// die den Filter Kriterien gengen
mcp2515_write_register(RXB0CTRL, (1<<RXM0));
#endif
}
else if (number == 2)
{
mask_address = RXM1SIDH;
#if SUPPORT_EXTENDED_CANID
if (filter->flags.extended == 0x3) {
// only extended identifier
mcp2515_write_register(RXB1CTRL, (1<<RXM1));
}
else if (filter->flags.extended == 0x2) {
// only standard identifier
mcp2515_write_register(RXB1CTRL, (1<<RXM0));
}
else {
mcp2515_write_register(RXB1CTRL, 0);
}
#else
// Buffer 1: Empfangen aller Nachrichten mit Standard Identifier
// die den Filter Kriterien gengen
mcp2515_write_register(RXB1CTRL, (1<<RXM0));
#endif
}
if (mask_address)
{
RESET(MCP2515_CS);
spi_putc(SPI_WRITE);
spi_putc(mask_address);
#if SUPPORT_EXTENDED_CANID
mcp2515_write_id(&filter->mask, (filter->flags.extended == 0x2) ? 0 : 1);
#else
mcp2515_write_id(&filter->mask);
#endif
SET(MCP2515_CS);
_delay_us(1);
}
// write filter
uint8_t filter_address;
if (number >= 3) {
number -= 3;
filter_address = RXF3SIDH;
}
else {
filter_address = RXF0SIDH;
}
RESET(MCP2515_CS);
spi_putc(SPI_WRITE);
spi_putc(filter_address | (number * 4));
#if SUPPORT_EXTENDED_CANID
mcp2515_write_id(&filter->id, (filter->flags.extended == 0x2) ? 0 : 1);
#else
mcp2515_write_id(&filter->id);
#endif
SET(MCP2515_CS);
_delay_us(1);
// restore previous mode
mcp2515_change_operation_mode( mode );
return true;
}
// ----------------------------------------------------------------------------
uint8_t mcp2515_send_message(const can_t *msg)
{
// Status des MCP2515 auslesen
uint8_t status = mcp2515_read_status(SPI_READ_STATUS);
/* Statusbyte:
*
* Bit Funktion
* 2 TXB0CNTRL.TXREQ
* 4 TXB1CNTRL.TXREQ
* 6 TXB2CNTRL.TXREQ
*/
uint8_t address;
if (_bit_is_clear(status, 2)) {
address = 0x00;
}
else {
// Alle Puffer sind belegt,
// Nachricht kann nicht verschickt werden
return 0;
}
RESET(MCP2515_CS);
spi_putc(SPI_WRITE_TX | address);
#if SUPPORT_EXTENDED_CANID
mcp2515_write_id(&msg->id, msg->flags.extended);
#else
mcp2515_write_id(&msg->id);
#endif
uint8_t length = msg->length & 0x0f;
// Ist die Nachricht ein "Remote Transmit Request" ?
if (msg->flags.rtr)
{
// Ein RTR hat zwar eine Laenge,
// enthaelt aber keine Daten
// Nachrichten Laenge + RTR einstellen
spi_putc((1<<RTR) | length);
}
else
{
// Nachrichten Laenge einstellen
spi_putc(length);
// Daten
for (uint8_t i=0;i<length;i++) {
spi_putc(msg->data[i]);
}
}
SET(MCP2515_CS);
_delay_us(1);
// CAN Nachricht verschicken
// die letzten drei Bit im RTS Kommando geben an welcher
// Puffer gesendet werden soll.
RESET(MCP2515_CS);
address = (address == 0) ? 1 : address;
spi_putc(SPI_RTS | address);
SET(MCP2515_CS);
CAN_INDICATE_TX_TRAFFIC_FUNCTION;
return address;
}
uint8_t mcp2515_set_filter(uint8_t number, const can_filter_t *filter)
{
uint8_t mask_address = 0;
if (number > 5)
return false;
// Konfiguration einschalten
mcp2515_change_operation_mode( (1<<REQOP2) );
// Filtermaske setzen
if (number == 0)
{
mask_address = RXM0SIDH;
}
else if (number == 2)
{
mask_address = RXM1SIDH;
}
if (mask_address)
{
RESET(MCP2515_CS);
spi_putc(SPI_WRITE);
spi_putc(mask_address);
mcp2515_write_id(&filter->mask);
asm volatile ("nop");
asm volatile ("nop");
SET(MCP2515_CS);
asm volatile ("nop");
asm volatile ("nop");
}
// Filter setzen
uint8_t filter_address;
if (number >= 3) {
number -= 3;
filter_address = RXF3SIDH;
}
else {
filter_address = RXF0SIDH;
}
RESET(MCP2515_CS);
spi_putc(SPI_WRITE);
spi_putc(filter_address | (number * 4));
mcp2515_write_id(&filter->id);
asm volatile ("nop");
asm volatile ("nop");
SET(MCP2515_CS);
asm volatile ("nop");
asm volatile ("nop");
if (number == 0)
{
mcp2515_write_register(RXB0CTRL, (1<<RXM1));
}
else if (number==2)
{
mcp2515_write_register(RXB1CTRL, (1<<RXM1));
} ;
// zurueck zum normalen modus
mcp2515_write_register(CANCTRL, 0);
return true;
}