Part Number: F29H850TU
I am working thru BIT rate configuration on the F29. It is for CAN classic at 500K. I am using 20MHz crystal. I am dividing 200MHz for a target of 20MHz CANA clk.
It has been a while and questioning these calculations. Can you please double chCANBitTimingCalculator.xls eck my numbers. What should they be. I was shooting for a 70 to 80% sample point. Thank you.
Hi Michal,
To summarize your calculations:
CPU_clk = 200Mhz
CAN_clk = 20Mhz [CPU CLK being divided ]
PreScalar = 4
TimeSeg1 = 3+3
TimeSeg2 = 3
BaudRate = CAN_clk/ (Prescalar)*(1 + TimeSeg1 + TimeSeg2)
= 20 / (4 * (1+3+3+3))
= 20 / 40
= 0.5 MHz = 500KHz
Sampling point = (1 + TimeSeg1 ) / 1 + TimeSeg1 + TimeSeg2
= (1+3+3) / (1+3+3+3)
= 7/10
= 70%
The calculation for both sampling point and baud rate seems good. This should achieve what you expect.
One small thing to pay attention to is the value being written into the register. If you plan on writing these values yourself, please observe that the value written has to be one less than what is intended. If you are using the SDK and MCAL offering, then you don't have to worry, this is taken care by he driver.
Regards,
Pranav Siddappa
