uint8_t mcp2515_get_filter(uint8_t number, can_filter_t *filter)
{
uint8_t mask_address;
uint8_t filter_address;
uint8_t temp;
uint8_t mode = mcp2515_read_register(CANSTAT);
if (number > 5)
return 0;
// change to configuration mode
mcp2515_change_operation_mode( (1<<REQOP2) );
if (number <= 1)
{
mask_address = RXM0SIDH;
temp = mcp2515_read_register(RXB0CTRL);
}
else
{
mask_address = RXM1SIDH;
temp = mcp2515_read_register(RXB1CTRL);
}
temp &= (1<<RXM1)|(1<<RXM0);
if (temp == 0) {
// filter and masks are disabled
#if SUPPORT_EXTENDED_CANID
filter->flags.extended = 0;
#endif
filter->flags.rtr = 0;
filter->mask = 0;
filter->id = 0;
return 1;
}
#if SUPPORT_EXTENDED_CANID
// transform bits so that they match the format from can.h
temp >>= 5;
temp = ~temp;
if (temp & 1) temp = 0x3;
filter->flags.extended = temp;
#endif
// read mask
RESET(MCP2515_CS);
spi_putc(SPI_READ);
spi_putc(mask_address);
mcp2515_read_id(&filter->mask);
SET(MCP2515_CS);
if (number <= 2)
{
filter_address = RXF0SIDH + number * 4;
}
else
{
filter_address = RXF3SIDH + (number - 3) * 4;
}
// read filter
RESET(MCP2515_CS);
spi_putc(SPI_READ);
spi_putc(filter_address);
mcp2515_read_id(&filter->id);
SET(MCP2515_CS);
// restore previous mode
mcp2515_change_operation_mode( mode );
return 1;
}
uint8_t mcp2515_get_message(can_t *msg)
{
uint8_t addr;
#ifdef RXnBF_FUNKTION
if (!IS_SET(MCP2515_RX0BF))
addr = SPI_READ_RX;
else if (!IS_SET(MCP2515_RX1BF))
addr = SPI_READ_RX | 0x04;
else
return 0;
#else
// read status
uint8_t status = mcp2515_read_status(SPI_RX_STATUS);
if (_bit_is_set(status,6)) {
// message in buffer 0
addr = SPI_READ_RX;
}
else if (_bit_is_set(status,7)) {
// message in buffer 1
addr = SPI_READ_RX | 0x04;
}
else {
// Error: no message available
return 0;
}
#endif
RESET(MCP2515_CS);
spi_putc(addr);
// CAN ID auslesen und ueberpruefen
uint8_t tmp = mcp2515_read_id(&msg->id);
#if SUPPORT_EXTENDED_CANID
msg->flags.extended = tmp & 0x01;
#else
if (tmp & 0x01) {
// Nachrichten mit extended ID verwerfen
SET(MCP2515_CS);
#ifdef RXnBF_FUNKTION
if (!IS_SET(MCP2515_RX0BF))
#else
if (_bit_is_set(status, 6))
#endif
mcp2515_bit_modify(CANINTF, (1<<RX0IF), 0);
else
mcp2515_bit_modify(CANINTF, (1<<RX1IF), 0);
return 0;
}
#endif
// read DLC
uint8_t length = spi_putc(0xff);
#ifdef RXnBF_FUNKTION
if (!(tmp & 0x01))
msg->flags.rtr = (tmp & 0x02) ? 1 : 0;
else
msg->flags.rtr = (length & (1<<RTR)) ? 1 : 0;
#else
msg->flags.rtr = (_bit_is_set(status, 3)) ? 1 : 0;
#endif
length &= 0x0f;
msg->length = length;
// read data
for (uint8_t i=0;i<length;i++) {
msg->data[i] = spi_putc(0xff);
}
SET(MCP2515_CS);
// clear interrupt flag
#ifdef RXnBF_FUNKTION
if (!IS_SET(MCP2515_RX0BF))
#else
if (_bit_is_set(status, 6))
#endif
mcp2515_bit_modify(CANINTF, (1<<RX0IF), 0);
else
mcp2515_bit_modify(CANINTF, (1<<RX1IF), 0);
CAN_INDICATE_RX_TRAFFIC_FUNCTION;
#ifdef RXnBF_FUNKTION
return 1;
#else
return (status & 0x07) + 1;
#endif
}
