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Diffstat (limited to 'docs/library/pyb.CAN.rst')
| -rw-r--r-- | docs/library/pyb.CAN.rst | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/docs/library/pyb.CAN.rst b/docs/library/pyb.CAN.rst index 57a85d54b..eb21d8223 100644 --- a/docs/library/pyb.CAN.rst +++ b/docs/library/pyb.CAN.rst @@ -67,11 +67,17 @@ Methods :meth:`~CAN.restart()` can be used to leave the bus-off state - *baudrate* if a baudrate other than 0 is provided, this function will try to automatically calculate the CAN nominal bit time (overriding *prescaler*, *bs1* and *bs2*) that satisfies - both the baudrate and the desired *sample_point*. - - *sample_point* given in a percentage of the nominal bit time, the *sample_point* specifies the position - of the bit sample with respect to the whole nominal bit time. The default *sample_point* is 75%. + both the *baudrate* (within .1%) and the desired *sample_point* (to the nearest 1%). For more precise + control over the CAN timing, set the *prescaler*, *bs1* and *bs2* parameters directly. + - *sample_point* specifies the position of the bit sample with respect to the whole nominal bit time, + expressed as an integer percentage of the nominal bit time. The default *sample_point* is 75%. + This parameter is ignored unless *baudrate* is set. - *num_filter_banks* for classic CAN, this is the number of banks that will be assigned to CAN(1), the rest of the 28 are assigned to CAN(2). + + The remaining parameters are only present on boards with CAN FD support, and configure the optional CAN FD + Bit Rate Switch (BRS) feature: + - *brs_prescaler* is the value by which the CAN FD input clock is divided to generate the data bit time quanta. The prescaler can be a value between 1 and 32 inclusive. - *brs_sjw* is the resynchronisation jump width in units of time quanta for data bits; @@ -82,10 +88,11 @@ Methods it can be a value between 1 and 16 inclusive - *brs_baudrate* if a baudrate other than 0 is provided, this function will try to automatically calculate the CAN data bit time (overriding *brs_prescaler*, *brs_bs1* and *brs_bs2*) that satisfies - both the baudrate and the desired *brs_sample_point*. - - *brs_sample_point* given in a percentage of the data bit time, the *brs_sample_point* specifies the position - of the bit sample with respect to the whole data bit time. The default *brs_sample_point* is 75%. - + both the *brs_baudrate* (within .1%) and the desired *brs_sample_point* (to the nearest 1%). For more + precise control over the BRS timing, set the *brs_prescaler*, *brs_bs1* and *brs_bs2* parameters directly. + - *brs_sample_point* specifies the position of the bit sample with respect to the whole nominal bit time, + expressed as an integer percentage of the nominal bit time. The default *brs_sample_point* is 75%. + This parameter is ignored unless *brs_baudrate* is set. The time quanta tq is the basic unit of time for the CAN bus. tq is the CAN prescaler value divided by PCLK1 (the frequency of internal peripheral bus 1); |