SAM3X8E Atmel Corporation, SAM3X8E Datasheet - Page 1210

• Manufacturer Part Number: SAM3X8E
• Manufacturer: Atmel Corporation

40.7.2.2
Table 40-4.
1210
1210
Receive with overwrite
Mailbox Object Type
SAM3X/A
SAM3X/A
Consumer
Receive
Receive Mailbox
When a message is received, the corresponding handler can be invoked using CAN_MFIDx reg-
ister and there is no need to check masked bits:
When the CAN module receives a message, it looks for the first available mailbox with the low-
est number and compares the received message ID with the mailbox ID. If such a mailbox is
found, then the message is stored in its data registers. Depending on the configuration, the mail-
box is disabled as long as the message has not been acknowledged by the application (Receive
only), or, if new messages with the same ID are received, then they overwrite the previous ones
(Receive with overwrite).
It is also possible to configure a mailbox in Consumer Mode. In this mode, after each transfer
request, a remote frame is automatically sent. The first answer received is stored in the corre-
sponding mailbox data registers.
Several mailboxes can be chained to receive a buffer. They must be configured with the same
ID in Receive Mode, except for the last one, which can be configured in Receive with Overwrite
Mode. The last mailbox can be used to detect a buffer overflow.
unsigned int MFID0_register;
MFID0_register = Get_CAN_MFID0_Register();
// Get_CAN_MFID0_Register() returns the value of the CAN_MFID0 register
pHandler[MFID0_register]();
Description
The first message received is stored in mailbox data registers. Data remain available until the
next transfer request.
The last message received is stored in mailbox data register. The next message always
overwrites the previous one. The application has to check whether a new message has not
overwritten the current one while reading the data registers.
A remote frame is sent by the mailbox. The answer received is stored in mailbox data register.
This extends Receive mailbox features. Data remain available until the next transfer request.
11057A–ATARM–17-Feb-12
11057A–ATARM–17-Feb-12