Datasheet

Figure 39-7. Rx FIFO Status
0
1
2
3
4
5
6
7
Get Index
RXFnS.FnGI
Put Index
RXFnS.FnPI
Fill Level
RXFnS.FnFI
When reading from an Rx FIFO, Rx FIFO Get Index RXFnS.FnGI • FIFO Element Size has to be added
to the corresponding Rx FIFO start address RXFnC.FnSA.
Table 39-3. Rx Buffer / FIFO Element Size
RXESC.RBDS[2:0]
RXESC.FnDS[2:0]
Data Field
[bytes]
FIFO Element Size
[RAM words]
000 8 4
001 12 5
010 16 6
011 20 7
100 24 8
101 32 10
110 48 14
111 64 18
Rx FIFO Blocking Mode
The Rx FIFO blocking mode is configured by RXFnC.FnOM = ‘0’. This is the default operation mode for
the Rx FIFOs.
When an Rx FIFO full condition is reached (RXFnS.FnPI = RXFnS.FnGI), no further messages are
written to the corresponding Rx FIFO until at least one message has been read out and the Rx FIFO Get
Index has been incremented. An Rx FIFO full condition is signaled by RXFnS.FnF = ‘1’. In addition
interrupt flag IR.RFnF is set.
In case a message is received while the corresponding Rx FIFO is full, this message is discarded and the
message lost condition is signalled by RXFnS.RFnL = ‘1’. In addition interrupt flag IR.RFnL is set.
Rx FIFO Overwrite Mode
The Rx FIFO overwrite mode is configured by RXFnC.FnOM = ‘1’.
SAM D5x/E5x Family Data Sheet
CAN - Control Area Network
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 1218