C8051F52X_12 Datasheet, PDF (169/221 Pages) Silicon Laboratories – 8/4/2 kB ISP Flash MCU Family

C8051F52x/F53x
17.3. LIN Master Mode Operation
The master node is responsible for the scheduling of messages and sends the header of each frame, con-
taining the SYNCH BREAK FIELD, SYNCH FIELD and IDENTIFIER FIELD. The steps to schedule a mes-
sage transmission or reception are listed below.
1. Load the 6-bit Identifier into the LIN0ID register.
2. Load the data length into the LIN0SIZE register. Set the value to the number of data bytes or "1111b" if
the data length should be decoded from the identifier. Also, set the checksum type, classic or
enhanced, in the same LIN0SIZE register.
3. Set the data direction by setting the TXRX bit (LIN0CTRL.5). Set the bit to 1 to perform a master
transmit operation, or set the bit to 0 to perform a master receive operation.
4. If performing a master transmit operation, load the data bytes to transmit into the data buffer (LIN0DT1
to LIN0DT8).
5. Set the STREQ bit (LIN0CTRL.0) to start the message transfer. The LIN peripheral will schedule the
message frame and request an interrupt if the message transfer is successfully completed or if an error
has occurred.
This code segment shows the procedure to schedule a message in a transmission operation:
LINADDR
LINDATA
LINADDR
LINDATA
LINADDR
LINDATA
= 0x08;// Point to LIN0CTRL
|= 0x20;// Select to transmit data
= 0x0E;// Point to LIN0ID
= 0x11;// Load the ID, in this example 0x11
= 0x0B;// Point to LIN0SIZE
= ( LINDATA & 0xF0 ) | 0x08; // Load the size with 8
LINADDR = 0x00;// Point to Data buffer first byte
for (i=0; i<8; i++)
{
LINDATA = i + 0x41;// Load the buffer with ‘A’, ‘B’, ...
LINADDR++;// Increment the address to the next buffer
}
LINADDR = 0x08;// Point to LIN0CTRL
LINDATA = 0x01;// Start Request
The application should perform the following steps when an interrupt is requested.
1. Check the DONE bit (LIN0ST.0) and the ERROR bit (LIN0ST.2).
2. If performing a master receive operation and the transfer was successful, read the received data from
the data buffer.
3. If the transfer was not successful, check the error register to determine the kind of error. Further error
handling has to be done by the application.
4. Set the RSTINT (LIN0CTRL.3) and RSTERR bits (LIN0CTRL.2) to reset the interrupt request and the
error flags.
Rev. 1.4
169