Datasheet

 2003-2019 Microchip Technology Inc. DS20001801J-page 5
MCP2515
1.4 Transmit/Receive Buffers/Masks/
Filters
The MCP2515 has three transmit and two receive
buffers, two acceptance masks (one for each receive
buffer) and a total of six acceptance filters. Figure 1-3
shows a block diagram of these buffers and their
connection to the protocol engine.
FIGURE 1-3: CAN BUFFERS AND PROTOCOL ENGINE BLOCK DIAGRAM
Acceptance Filter
RXF2
R
X
B
1
Identifier
Data Field Data Field
Identifier
Acceptance Mask
RXM1
Acceptance Filter
RXF3
Acceptance Filter
RXF4
Acceptance Filter
RXF5
M
A
B
Acceptance Filter
RXF0
Acceptance Filter
RXF1
R
X
B
0
TXREQ
TXB2
ABTF
MLOA
TXERR
MESSAGE
Message
Queue
Control
TXREQ
TXB0
ABTF
MLOA
TXERR
MESSAGE
Comparator
Receive
Error
Transmit
Error
Protocol
REC
TEC
ErrPas
BusOff
Finite
State
Machine
Counter
Counter
Shift[14:0]
{Transmit[5:0], Receive[8:0]}
Transmit
Logic
TX RX
Configuration
Registers
Clock
Generator
PROTOCOL
ENGINE
BUFFERS
TXREQ
TXB1
ABTF
MLOA
TXERR
MESSAGE
Acceptance Mask
RXM0
A
c
c
e
p
t
A
c
c
e
p
t
SOF
Bit
Timing
Logic
Receive[7:0]Transmit]7:0]
Transmit Byte Sequencer
CRC[14:0]