Test Loop Back Mode; Test Error Mode; Figure 3.7 Flowchart Of Setup Of Test Loop Back Mode And Test Error Mode - Toshiba TXZ+ Series Reference Manual

Test Loop Back Mode

In test loop back mode, the CAN controller can receive its own transmitted message and generates its own
acknowledge bit. No other CAN node is necessary for the operation.
The test loop back mode can be enabled or disabled only when the CAN controller is in suspend mode. In test loop
back mode, the CAN controller can transmit a message from a mailbox and receive it in another mailbox.
The setup for mailbox is the same as in normal operation mode.

Test Error Mode

In test error mode, writes to the CAN error counter register [CANxCEC] are possible. The values of the lower 8
bits are concurrently written to both the transmission error counter (TEC) and the reception error counter (REC).
The maximum value that can be written into the error counters is "255". The error counter value of "256" which
forces the CAN controller into bus off mode cannot be written.
The test error mode can be enabled or disabled only when the CAN controller is in suspend mode.
Figure 3.7 shows the flowchart of the setup of test loop-back mode and test error mode.

Figure 3.7 Flowchart of Setup of Test Loop Back Mode and Test Error Mode

Enable/disable
test loop back mode and
test error mode
CAN is in normal operation mode:
[CANxMCR]<CCR> = 0 & [CANxGSR]<CCE> = 0
[CANxMCR]<SUR> = 0 & [CANxGSR]<SUA> = 0
Suspend mode request:
[CANxGSR]<SUA> = 1 ?
Yes
Setup [CANxMCR]<TSTLB> and/or
[CANxMCR]<TSTERR> bit:
"1" enable,"0" disable
Back to normal operation mode with
enabled/disabled [CANxMCR]<TSTLB> and/or
[CANxMCR]<TSTERR>: set [CANxGSR]<SUR> to "0"
[CANxGSR]<SUA> = 0 ?
Yes
End of setup:
CAN is in normal operation mode
with enabled/disabled test loop
back and/or test error mode
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No
No
TXZ+ Family
CAN Controller
2020-10-01
Rev. 1.0