CP3BT23_14 Datasheet, PDF (155/324 Pages) Texas Instruments – CP3BT23 Reprogrammable Connectivity Processor with Bluetooth and Dual CAN Interfaces

www.ti.com
CP3BT23
SNOSCX3A – JULY 2013 – REVISED JANUARY 2014
Sequence of Data Bytes on the Bus
ID
Data1
Data2
Data3
Data4
Data5
Data6
Data7
Data8
CRC
Storage of Data Bytes
in the Buffer Memory
ADDR Offset
0A₁₆
08 ₁₆
06 16
04 16
Data Bytes
Data1
Data2
Data3
Data4
Data5
Data7
Data6
Data8
Figure 18-28. Data Direction Bit Clear
t
DS045
Setting the DDIR bit will cause the direction of the data storage to be reversed — the last byte received is
stored at the highest address and the first byte is stored at the lowest address, as shown in Figure 18-29.
Sequence of Data Bytes on the Bus
ID
Data1
Data2
Data3
Data4
Data5
Data6
Data7
Data8
CRC
Storage of Data Bytes
in the Buffer Memory
ADDR Offset
0A 16
0816
0616
04₁₆
Data Bytes
Data8
Data7
Data6
Data5
Data4
Data2
Data3
Data1
Figure 18-29. Data Direction Bit Set
t
DS046
LO
The Listen Only bit can be used to configure the CAN interface to behave only as a
receiver. This means:
• Cannot transmit any message.
• Cannot send a dominant ACK bit.
• When errors are detected on the bus, the CAN module will behave as in the error
passive mode.
Using this listen only function, the CAN interface can be adjusted for connecting to an
operating network with unknown bus speed.
0 – Transmit/receive mode.
1 – Listen-only mode.
IGNACK
When the Ignore Acknowledge bit is set, the CAN module does not expect to receive a
dominant ACK bit to indicate the validity of a transmitted message. It will not send an error
frame when the transmitted frame is not acknowledged by any other CAN node. This
feature can be used in conjunction with the LOOPBACK bit for stand-alone tests outside of
a CAN network.
0 – Normal mode.
1 – The CAN module does not expect to receive a dominant ACK bit to indicate the validity
of a transmitted message.
LOOPBACK When the Loopback bit is set, all messages sent by the CAN module can also be received
by a CAN module buffer with a matching buffer ID. However, the CAN module does not
acknowledge a message sent by itself. Therefore, the CAN module will send an error
frame when no other device connected to the bus has acknowledged the message.
0 – No loopback.
1 – Loopback enabled.
Copyright © 2013–2014, Texas Instruments Incorporated
Submit Documentation Feedback
Product Folder Links: CP3BT23
CAN Module 155