// macro to format the timing register value from the timing parameters
#define CAN_TIMING(tseg1, tseg2, sjw, brp) (((tseg2-1) & 0x07) << 12) | (((tseg1-1) & 0x0F) << 8) | (((sjw-1) & 0x03) << 6) | ((brp-1) & 0x3F)
/*******************************************************************************
* Function Name : CAN_SetTiming
* Description : Setup the CAN timing with specific parameters
* Input 1 : Time Segment before the sample point position, from 2 to 16
* Input 2 : Time Segment after the sample point position, from 1 to 8
* Input 3 : Synchronisation Jump Width, from 1 to 4
* Input 4 : Baud Rate Prescaler, from 1 to 1024
* Output : None
* Return : None
* Note : CAN must be in initialization mode
*******************************************************************************/
void CAN_SetTiming(u32 tseg1, u32 tseg2, u32 sjw, u32 brp)
{
CAN->BTR = CAN_TIMING(tseg1, tseg2, sjw, brp);
CAN->BRPR = ((brp-1) >> 6) & 0x0F;
}
//------------------------------------------------------------------------------
// write the predefined timing value
//------------------------------------------------------------------------------
void ECU_CAN_SetupBaudRate(u32 dwBaudRate)
{
u32 brp;
if (dwBaudRate <= 500000)
{
brp = (24000000 / 16) / dwBaudRate;
CAN_SetTiming(11, 4, 4, brp);
}
else if (dwBaudRate <= 1000000)
{
brp = (24000000 / 8 ) / dwBaudRate;
CAN_SetTiming( 4, 3, 3, brp);
}
CAN->BRPR = 0;
}
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