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2.16 Overwrite Protection Control Register (CANOPC)
Overwrite Protection Control Register (CANOPC)
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If there is an overflow condition for mailbox n (RMP[
n
] is set to 1 and a new receive message would fit for
mailbox n), the new message is stored depending on the settings in the CANOPC register. If the
corresponding bit OPC[
n
] is set to 1, the old message is protected against being overwritten by the new
message; thus, the next mailboxes are checked for a matching ID. If no other mailbox is found, the
message is lost without further notification. If the bit OPC[
n
] is cleared to 0, the old message is overwritten
by the new one. This is notified by setting the receive message lost bit RML[
n
].
For read/write operations, only 32-bit access is supported.
Figure 2-21. Overwrite Protection Control Register (CANOPC)
31
0
OPC.31:0
R/W-0
LEGEND: R/W = Read/Write; -
n
= value after reset
Table 2-18. Overwrite Protection Control Register (CANOPC) Field Descriptions
Bit
Field
Value
Description
31:0
OPC.31:0
Overwrite protection control bits
1
1 If the bit OPC[
n
] is set to 1, an old message stored in that mailbox is protected against being
overwritten by the new message.
0
0 If the bit OPC[
n
] is not set, the old message can be overwritten by a new one.
eCAN Registers
52
SPRU074F – May 2002 – Revised January 2009