garygid
Well-known member
The third step in using the CAN transceiver:
3. Attaching pin 5 and pin 8, if necessary.
For now, with my TI 235 transceiver chip, the pin 5 is "AB" and
can be left open for most normal operation. The pin 8 is "RS",
and is common on many transceiver chips, and needs to be
connected to ground, in my case through a 10k resistor would
be satisfactory.
4. Connection to the Due "primary" CAN port, which has dedicated pins:
CANTX on D69, which should be connected to the transceiver
pin 1 (called "D", used for transmitting message Data) and
CANRX on D68, which should be connected to the transceiver
pin 4 (called "R", used for Receiving the data on the CAN bus).
5. To connect one (properly terminated and biased) transceiver
to another, simply connect each CANH together, and each CAN
together. If more than two "nodes" are connected, they should
be short "taps" on a single twisted pair, and not a "star" type
configuration. The ends of the twisted pair (or sometimes not
twisted) should be properly terminsted. One place on the
CAN bus should be biased.
Hopefully this will be helpful to some, but old-hat to others.
Please, if there are errors, let me know so that I can fix them.
And, if there are better ideas, please feel free to suggest them.
Note: If you were making a Due CAN "node" to talk to the LEAF's
QC bus, you would include termination and bias.
However, I strongly recommend building two nodes, and testing
them considerably, before ever trying to talk to the QC bus,
which might require (probably requires) specific handshake signals
before it would even activate.
I intend to make a node to simulate a car's QC port, and a another
node to simulate a QC device, including the two CAN bus wires,
a ground, and the four Handshake lines (7 lines total).
When these work well, and I have the logging working, then I
could simulate a start-QC sequence, and log and graph the data.
Then, a parallel effort is to obtain a suitably controllable power supply,
probably lower power to start, and make sure that its voltage output
will respond satisfactorily in the simulated start-charging sequence.
Graphing the Output Voltage would verify the logging to CAN-Do.
more later...
Finally, I would care
3. Attaching pin 5 and pin 8, if necessary.
For now, with my TI 235 transceiver chip, the pin 5 is "AB" and
can be left open for most normal operation. The pin 8 is "RS",
and is common on many transceiver chips, and needs to be
connected to ground, in my case through a 10k resistor would
be satisfactory.
4. Connection to the Due "primary" CAN port, which has dedicated pins:
CANTX on D69, which should be connected to the transceiver
pin 1 (called "D", used for transmitting message Data) and
CANRX on D68, which should be connected to the transceiver
pin 4 (called "R", used for Receiving the data on the CAN bus).
5. To connect one (properly terminated and biased) transceiver
to another, simply connect each CANH together, and each CAN
together. If more than two "nodes" are connected, they should
be short "taps" on a single twisted pair, and not a "star" type
configuration. The ends of the twisted pair (or sometimes not
twisted) should be properly terminsted. One place on the
CAN bus should be biased.
Hopefully this will be helpful to some, but old-hat to others.
Please, if there are errors, let me know so that I can fix them.
And, if there are better ideas, please feel free to suggest them.
Note: If you were making a Due CAN "node" to talk to the LEAF's
QC bus, you would include termination and bias.
However, I strongly recommend building two nodes, and testing
them considerably, before ever trying to talk to the QC bus,
which might require (probably requires) specific handshake signals
before it would even activate.
I intend to make a node to simulate a car's QC port, and a another
node to simulate a QC device, including the two CAN bus wires,
a ground, and the four Handshake lines (7 lines total).
When these work well, and I have the logging working, then I
could simulate a start-QC sequence, and log and graph the data.
Then, a parallel effort is to obtain a suitably controllable power supply,
probably lower power to start, and make sure that its voltage output
will respond satisfactorily in the simulated start-charging sequence.
Graphing the Output Voltage would verify the logging to CAN-Do.
more later...
Finally, I would care