R01UH0823EJ0100 Rev.1.00
Page 1277 of 1823
Jul 31, 2019
RX23W Group
36. CAN Module (RSCAN)
36.6.3
Self-Test Mode (Loopback Mode)
In self-test mode, transmitted messages are compared with the receive rule of the own channel and the messages are
stored in a buffer if they have passed through the filter processing. Messages transmitted from other CAN nodes are
compared only with the receive rule for which the GAFLIDHj.GAFLLB bit is set to 0 (when a message transmitted from
another CAN node is received).
If the mirror function and self-test mode are both enabled, the self-test mode setting takes precedence.
(1) Self-Test Mode 0 (External Loopback Mode)
Self-test mode 0 is used to perform a loopback test within a channel including the CAN transceiver.
In self-test mode 0, transmitted messages are handled as messages received through the CAN transceiver and are stored
in a buffer. An ACK bit is generated to receive messages transmitted from the own CAN node.
shows the connection when self-test mode 0 is selected.
Figure 36.11
Connection When Self-Test Mode 0 is Selected
(2) Self-Test Mode 1 (Internal Loopback Mode)
In self-test mode 1, transmitted messages are handled as received messages and are stored in a buffer. An ACK bit is
generated to receive messages transmitted from the own CAN node.
In self-test mode 1, internal feedback from the internal CTXD0 pin to the internal CRXD0 pin is performed. The external
CRXD0 pin input is isolated. The external CTXD0 pin outputs only recessive bits.
shows the connection when self-test mode 1 is selected.
Figure 36.12
Connection When Self-Test Mode 1 is Selected
36.6.4
RAM Test
The RAM test function allows accesses to all CAN RAM addresses.
When the RAM test function is used, the RAM is divided into pages of 256 bytes each. RAM test page is set by the
GTSTCFG.RTMPS[2:0] bits. Data in the set page can be read from and written to the RPGACCr register. The available
total RAM size is 544 bytes (0220h).
CTXD0
CRXD0
CTXD0
(internal)
CRXD0
(internal)
CAN transceiver
ACK
CTXD0
CRXD0
CTXD0
(internal)
CRXD0
(internal)
ACK
Recessive level