djsundog/circuitpython
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Update documentation for the CAN class

Browse Source
This commit is contained in:
Henrik Sölver 2014-11-29 22:29:06 +01:00 committed by Damien George
parent b2e731177e
commit d8c2b2a1c4
1 changed files with 52 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
docs/library/pyb.CAN.rst
View File

@ -7,15 +7,12 @@ to connect the pyboard to a CAN bus you must use a CAN transceiver
to convert the CAN logic signals from the pyboard to the correct
voltage levels on the bus.
Note that this driver does not yet support filter configuration
(it defaults to a single filter that lets through all messages),
or bus timing configuration (except for setting the prescaler).
Example usage (works without anything connected)::
from pyb import CAN
can = pyb.CAN(1, pyb.CAN.LOOPBACK)
can.send('message!', 123) # send message to id 123
can = CAN(1, CAN.LOOPBACK)
can.setfilter(0, CAN.LIST16, 0, (123, 124, 125, 126)) # set a filter to receive messages with id=123, 124, 125 and 126
can.send('message!', 123) # send a message with id 123
can.recv(0) # receive message on FIFO 0
@ -35,7 +32,17 @@ Constructors
- ``CAN(1)`` is on ``YA``: ``(RX, TX) = (Y3, Y4) = (PB8, PB9)``
- ``CAN(2)`` is on ``YB``: ``(RX, TX) = (Y5, Y6) = (PB12, PB13)``
Class Methods
-------------
.. method:: CAN.initfilterbanks(nr)
Reset and disable all filter banks and assign how many banks should be available for CAN(1).
STM32F405 has 28 filter banks that are shared between the two available CAN bus controllers.
This function configures how many filter banks should be assigned to each. ``nr`` is the number of banks
that will be assigned to CAN(1), the rest of the 28 are assigned to CAN(2).
At boot, 14 banks are assigned to each controller.
Methods
-------
@ -75,6 +82,37 @@ Methods
Turn off the CAN bus.
.. method:: can.setfilter(bank, mode, fifo, params)
Configure a filter bank:
- ``bank`` is the filter bank that is to be configured.
- ``mode`` is the mode the filter should operate in.
- ``fifo`` is which fifo (0 or 1) a message should be stored in, if it is accepted by this filter.
- ``params`` is an array of values the defines the filter. The contents of the array depends on the ``mode`` argument.
+-----------+---------------------------------------------------------+
|``mode`` |contents of parameter array |
+===========+=========================================================+
|CAN.LIST16 |Four 16 bit ids that will be accepted |
+-----------+---------------------------------------------------------+
|CAN.LIST32 |Two 32 bit ids that will be accepted |
+-----------+---------------------------------------------------------+
|CAN.MASK16 |Two 16 bit id/mask pairs. E.g. (1, 3, 4, 4) |
| | | The first pair, 1 and 3 will accept all ids |
| | | that have bit 0 = 1 and bit 1 = 0. |
| | | The second pair, 4 and 4, will accept all ids |
| | | that have bit 2 = 1. |
+-----------+---------------------------------------------------------+
|CAN.MASK32 |As with CAN.MASK16 but with only one 32 bit id/mask pair.|
+-----------+---------------------------------------------------------+
.. method:: can.clearfilter(bank)
Clear and disables a filter bank:
- ``bank`` is the filter bank that is to be cleared.
.. method:: can.any(fifo)
Return ``True`` if any message waiting on the FIFO, else ``False``.
@ -98,7 +136,6 @@ Methods
Return value: ``None``.
Constants
---------
@ -108,3 +145,10 @@ Constants
.. data:: CAN.SILENT_LOOPBACK
the mode of the CAN bus
.. data:: CAN.LIST16
.. data:: CAN.MASK16
.. data:: CAN.LIST32
.. data:: CAN.MASK32
the operation mode of a filter