AN1278 datasheet(40/44 Pages) STMICROELECTRONICS

Part #	AN1278

Description	Many mechanical components in the automotive sector have been replaced

PDF	44 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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LIN (LOCAL INTERCONNECT NETWORK) SOLUTIONS

Figure 19. OC interrupt Handling in Reception Mode

4.4.2.2 Transmission

For transmission the software only uses the Output Compare feature of the 16-bit timer. For

each bit, two OC interrupts are generated. The first one is generated to output the value of the

new bit. The second is used to read back the bus and check whether the output value is actu-

ally being sent, in other words to check for a bit error. See Figure 20.

Figure 20. SCI emulation: LIN Transmission

The bit transition time is precise because the timer output compare itself outputs the new level

when an output compare event occurs. Software delays do not influence the bit transitions.

The first OC sets a new OC for the middle of the bit. The second reads the LIN bus level and

prepares the next OC to output the next bit.

As a result the application software should not:

1 bit

application task

deadline for

start of OC interrupt

OC request

OC interrupt served

1 bit

1st OC:

2nd OC:

output new bit

read back

AN1278 Datasheet(PDF) 40 Page - STMicroelectronics