AnsweredAssumed Answered

STMF0x + CANbx + HSI48?

Question asked by davies.lee on Feb 21, 2017
Latest reply on Feb 21, 2017 by T J
Hi,
My using the STM32F072 with CANBus. I was going to use the HSI48 throughout however I discovered an issue. 
According to the Bosch CAN specification...
"A maximum oscillator tolerance of 1.58% is given and therefore the use of a ceramic resonator at a bus speed of up to 125 Kbits/s as a rule of thumb
 
I was going to run the CANBus at 250Kbits/s using the HSI48, however the STM32F072 User Manual highlights an issue...
"the HSI48 RC oscillator runs on its default frequency which is subject to manufacturing process variations, this is why each device is factory calibrated by ST for ~3% accuracy at TA = 25°C"
 
I could get away with using the HSI (+PLL), since the STM32F072 User Manual quotes better HSI accuracy...
"the HSI RC oscillator frequencies can vary from one chip to another due to manufacturing process variations, this is why each device is factory calibrated by ST for 1% accuracy at TA=25°C"
 
Has anybody had any experience running CAN with internal clocks?
Cheers,
Lee

Outcomes