AN1278 datasheet(31/44 Pages) STMICROELECTRONICS

31 / 44 page

31/44

LIN (LOCAL INTERCONNECT NETWORK) SOLUTIONS

scribed in 3.2.2 User interface functions the application is responsible for the initialization and

the interrupt routine.

Initialization:

Firstly, the output compare must be configured: The OCIE flag of the TACR1 register must be

set and the defined OC disabled by writing the high byte of the OC1 register. As the applica-

tion is not using OC2 it is disabled also in the same way.

Secondly, the timer prescaler must be calculated using the equations given in Table 7:

1st test: prescaler=2

(FCPU/prescaler/BAUDRATE)*165= 8000000/2/9600*165=68750 > 65536 doesn’t match

1st test: prescaler=4

(FCPU/prescaler/BAUDRATE)*165= 8000000/4/9600*165=34375 < 65536 match!

The prescaler has to be set to 4 which corresponds to writing the value (0,0) in the (CC0,CC1)

bits in Timer A Control Register 2.

extern uByte master_data[];

void DataReceived_Notification(@tiny t_header *header, @tiny t_response *re-

sponse)

{

if(header->identifier == ID_Table[0].id){

master_data[0]=response->data[0];

master_data[1]=response->data[1];

}

else if(header->identifier == ID_Table[2].id){

PORTS_WakeUp_On();

_asm("halt\n");

}

@interrupt void PORTS_0_Interrupt(void)

{

unsigned char i;

i=250;

while(i--);

if(!(PADR&0xFE))

{

PAOR&=0xFE;

LIN_SendWakeUpSignal();

}

on-chip SCI used

(FCPU/prescaler/BAUDRATE)*165 < 65536

AN1278 Datasheet(PDF) 31 Page - STMicroelectronics