upd70f3422gj-gae-qs-ax Renesas Electronics Corporation., upd70f3422gj-gae-qs-ax Datasheet - Page 661

• Manufacturer Part Number: upd70f3422gj-gae-qs-ax
• Description: 32-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

CAN Controller (CAN)
Caution
Caution
(6)
(b) Forced recovery operation that skips bus-off recovery sequence
The CAN module can be forcibly released from the bus-off state, regardless of
the bus state, by skipping the bus-off recovery sequence. Here is the
procedure.
First, the CAN module requests to enter the initialization mode. For the
operation and points to be noted at this time, “Recovery from bus-off state
through normal recovery sequence“ on page 659.
Next, the module requests to enter an operation mode. At the same time, the
CnCTRL.CCERC bit must be set to 1.
As a result, the bus-off recovery sequence defined by the CAN protocol ISO
11898 is skipped, and the module immediately enters the operation mode. In
this case, the module is connected to the CAN bus after it has monitored 11
consecutive recessive-level bits. For details, refer to the processing in Figure
19-51 on page 762.
This function is not defined by the CAN protocol ISO 11898. When using this
function, thoroughly evaluate its effect on the network system.
Initializing CAN module error counter register (CnERC) in initialization
mode
If it is necessary to initialize the CnERC and CnINFO registers for debugging
or evaluating a program, they can be initialized to the default value by setting
the CnCTRL.CCERC bit in the initialization mode. When initialization has been
completed, the CCERC bit is automatically cleared to 0.
1.
2.
Preliminary User’s Manual U17566EE1V2UM00
This function is enabled only in the initialization mode. Even if the CCERC
bit is set to 1 in a CAN operation mode, the CnERC and CnINFO registers
are not initialized.
The CCERC bit can be set at the same time as the request to enter a CAN
operation mode.
Chapter 19
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