MICROCHIP MCP2510T-E/SO

MCP2510
Stand-Alone CAN Controller with SPI™ Interface
Features
Description
• Implements Full CAN V2.0A and V2.0B at 1 Mb/s:
- 0 - 8 byte message length
- Standard and extended data frames
- Programmable bit rate up to 1 Mb/s
- Support for remote frames
- Two receive buffers with prioritized message
storage
- Six full acceptance filters
- Two full acceptance filter masks
- Three transmit buffers with prioritization and
abort features
- Loop-back mode for self test operation
• Hardware Features:
- High Speed SPI Interface
(5 MHz at 4.5V I temp)
- Supports SPI modes 0,0 and 1,1
- Clock out pin with programmable prescaler
- Interrupt output pin with selectable enables
- ‘Buffer full’ output pins configureable as interrupt pins for each receive buffer or as general
purpose digital outputs
- ‘Request to Send’ input pins configureable as
control pins to request immediate message
transmission for each transmit buffer or as
general purpose digital inputs
- Low Power Sleep mode
• Low power CMOS technology:
- Operates from 3.0V to 5.5V
- 5 mA active current typical
- 10 µA standby current typical at 5.5V
• 18-pin PDIP/SOIC and 20-pin TSSOP packages
• Temperature ranges supported:
- Industrial (I):
-40°C to +85°C
- Extended (E):
-40°C to +125°C
The Microchip Technology Inc. MCP2510 is a Full Controller Area Network (CAN) protocol controller implementing CAN specification V2.0 A/B. It supports CAN
1.2, CAN 2.0A, CAN 2.0B Passive, and CAN 2.0B
Active versions of the protocol, and is capable of transmitting and receiving standard and extended messages. It is also capable of both acceptance filtering
and message management. It includes three transmit
buffers and two receive buffers that reduce the amount
of microcontroller (MCU) management required. The
MCU communication is implemented via an industry
standard Serial Peripheral Interface (SPI) with data
rates up to 5 Mb/s.
18 LEAD PDIP/SOIC
TXCAN
1
18
VDD
RXCAN
2
17
RESET
CLKOUT
3
16
CS
TX0RTS
4
15
SO
TX1RTS
5
14
SI
13
SCK
12
INT
TX2RTS
6
OSC2
7
MCP2510
OSC1
8
11
RX0BF
VSS
9
10
RX1BF
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
VDD
RESET
CS
SO
SI
NC
SCK
INT
RX0BF
RX1BF
20 LEAD TSSOP
TXCAN
RXCAN
CLKOUT
TX0RTS
TX1RTS
NC
TX2RTS
OSC2
OSC1
VSS
MCP2510
© 2007 Microchip Technology Inc.
Package Types
DS21291F-page 1
MCP2510
Table of Contents
1.0
Device Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.0
Can Message Frames. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.0
Message Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.0
Message Reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.0
Bit Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
6.0
Error Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
7.0
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
8.0
Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.0
Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
10.0
Register Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
11.0
SPI Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
12.0
Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
13.0
Packaging Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
On-Line Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Reader Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Product Identification System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Worldwide Sales and Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined
and enhanced as new volumes and updates are introduced.
If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via
E-mail at [email protected] or fax the Reader Response Form in the back of this data sheet to (480) 792-4150. We
welcome your feedback.
Most Current Data Sheet
To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:
http://www.microchip.com
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.
The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).
Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision of silicon and revision of document to which it applies.
To determine if an errata sheet exists for a particular device, please check with one of the following:
• Microchip’s Worldwide Web site; http://www.microchip.com
• Your local Microchip sales office (see last page)
When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are
using.
Customer Notification System
Register on our web site at www.microchip.com to receive the most current information on all of our products.
DS21291F-page 2
© 2007 Microchip Technology Inc.
MCP2510
1.0
DEVICE FUNCTIONALITY
1.1
Overview
checked for errors and then matched against the user
defined filters to see if it should be moved into one of
the two receive buffers.
The MCU interfaces to the device via the SPI interface.
Writing to and reading from all registers is done using
standard SPI read and write commands.
The MCP2510 is a stand-alone CAN controller developed to simplify applications that require interfacing
with a CAN bus. A simple block diagram of the
MCP2510 is shown in Figure 1-1. The device consists
of three main blocks:
1.
2.
3.
Interrupt pins are provided to allow greater system flexibility. There is one multi-purpose interrupt pin as well
as specific interrupt pins for each of the receive registers that can be used to indicate when a valid message
has been received and loaded into one of the receive
buffers. Use of the specific interrupt pins is optional,
and the general purpose interrupt pin as well as status
registers (accessed via the SPI interface) can also be
used to determine when a valid message has been
received.
The CAN protocol engine.
The control logic and SRAM registers that are
used to configure the device and its operation.
The SPI protocol block.
A typical system implementation using the device is
shown in Figure 1-2.
The CAN protocol engine handles all functions for
receiving and transmitting messages on the bus. Messages are transmitted by first loading the appropriate
message buffer and control registers. Transmission is
initiated by using control register bits, via the SPI interface, or by using the transmit enable pins. Status and
errors can be checked by reading the appropriate registers. Any message detected on the CAN bus is
FIGURE 1-1:
There are also three pins available to initiate immediate
transmission of a message that has been loaded into
one of the three transmit registers. Use of these pins is
optional and initiating message transmission can also
be done by utilizing control registers accessed via the
SPI interface.
Table 1-1 gives a complete list of all of the pins on the
MCP2510.
BLOCK DIAGRAM
RXCAN
2 RX Buffers
CAN
Protocol
Engine
TXCAN
3 TX
Buffers
6 Acceptance
Filters
Message Assembly
Buffer
SPI
Interface
Logic
CS
SCK
SI
SPI
Bus
SO
Control Logic
INT
RX0BF
RX1BF
TX0RTS
TX1RTS
TX2RTS
© 2007 Microchip Technology Inc.
DS21291F-page 3
MCP2510
FIGURE 1-2:
TYPICAL SYSTEM IMPLEMENTATION
Main
System
Controller
MCP2510
CAN
Transceiver
CAN
BUS
CAN
Transceiver
CAN
Transceiver
CAN
Transceiver
CAN
Transceiver
MCP2510
MCP2510
MCP2510
MCP2510
Node
Controller
Node
Controller
Node
Controller
Node
Controller
SPI
INTERFACE
TABLE 1-1:
PIN DESCRIPTIONS
DIP/
SOIC
Pin #
TSSOP
Pin #
I/O/P
Type
TXCAN
1
1
O
Transmit output pin to CAN bus
RXCAN
2
2
I
Receive input pin from CAN bus
CLKOUT
3
3
O
Clock output pin with programmable prescaler
TX0RTS
4
4
I
Transmit buffer TXB0 request to send or general purpose digital input. 100 kΩ
internal pullup to VDD
TX1RTS
5
5
I
Transmit buffer TXB1 request to send or general purpose digital input. 100 kΩ
internal pullup to VDD
TX2RTS
6
7
I
Transmit buffer TXB2 request to send or general purpose digital input. 100 kΩ
internal pullup to VDD
OSC2
7
8
O
Oscillator output
OSC1
8
9
I
Oscillator input
VSS
9
10
P
Ground reference for logic and I/O pins
RX1BF
10
11
O
Receive buffer RXB1 interrupt pin or general purpose digital output
RX0BF
11
12
O
Receive buffer RXB0 interrupt pin or general purpose digital output
INT
12
13
O
Interrupt output pin
SCK
13
14
I
Clock input pin for SPI interface
SI
14
16
I
Data input pin for SPI interface
SO
15
17
O
Data output pin for SPI interface
CS
16
18
I
Chip select input pin for SPI interface
RESET
17
19
I
Active low device reset input
VDD
18
20
P
Positive supply for logic and I/O pins
NC
—
6,15
—
No internal connection
Name
Note:
Description
Type Identification: I=Input; O=Output; P=Power
DS21291F-page 4
© 2007 Microchip Technology Inc.
MCP2510
1.2
Transmit/Receive Buffers
The MCP2510 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 is a block diagram of these buffers and their connection to the protocol engine.
FIGURE 1-3:
CAN BUFFERS AND PROTOCOL ENGINE BLOCK DIAGRAM
Acceptance Mask
RXM1
BUFFERS
Acceptance Filter
RXF2
Message
Queue
Control
MESSAGE
TXREQ
ABTF
MLOA
TXERR
TXB2
MESSAGE
TXREQ
ABTF
MLOA
TXERR
TXB1
MESSAGE
TXREQ
ABTF
MLOA
TXERR
TXB0
A
c
c
e
p
t
R
X
B
0
Acceptance Mask
RXM0
Acceptance Filter
RXF3
Acceptance Filter
RXF0
Acceptance Filter
RXF4
Acceptance Filter
RXF1
Acceptance Filter
RXF5
M
A
B
Identifier
Data Field
Transmit Byte Sequencer
A
c
c
e
p
t
R
X
B
1
Identifier
Data Field
Receive
Error
Counter
PROTOCOL
ENGINE
Transmit<7:0>
Transmit
Error
Counter
Receive<7:0>
REC
TEC
ErrPas
BusOff
Shift<14:0>
{Transmit<5:0>, Receive<8:0>}
Comparator
Protocol
Finite
State
Machine
CRC<14:0>
Transmit
Logic
Bit
Timing
Logic
TX
RX
Clock
Generator
Configuration
Registers
© 2007 Microchip Technology Inc.
DS21291F-page 5
MCP2510
1.3
CAN Protocol Engine
1.6
The CAN protocol engine combines several functional
blocks, shown in Figure 1-4. These blocks and their
functions are described below.
1.4
Protocol Finite State Machine
The heart of the engine is the Finite State Machine
(FSM). This state machine sequences through messages on a bit by bit basis, changing states as the fields
of the various frame types are transmitted or received.
The FSM is a sequencer controlling the sequential data
stream between the TX/RX Shift Register, the CRC
Register, and the bus line. The FSM also controls the
Error Management Logic (EML) and the parallel data
stream between the TX/RX Shift Registers and the
buffers. The FSM insures that the processes of reception, arbitration, transmission, and error signaling are
performed according to the CAN protocol. The automatic retransmission of messages on the bus line is
also handled by the FSM.
1.5
Cyclic Redundancy Check
The Cyclic Redundancy Check Register generates the
Cyclic Redundancy Check (CRC) code which is transmitted after either the Control Field (for messages with
0 data bytes) or the Data Field, and is used to check the
CRC field of incoming messages.
FIGURE 1-4:
Error Management Logic
The Error Management Logic is responsible for the
fault confinement of the CAN device. Its two counters,
the Receive Error Counter (REC) and the Transmit
Error Counter (TEC), are incremented and decremented by commands from the Bit Stream Processor.
According to the values of the error counters, the CAN
controller is set into the states error-active, error-passive or bus-off.
1.7
Bit Timing Logic
The Bit Timing Logic (BTL) monitors the bus line input
and handles the bus related bit timing according to the
CAN protocol. The BTL synchronizes on a recessive to
dominant bus transition at Start of Frame (hard synchronization) and on any further recessive to dominant
bus line transition if the CAN controller itself does not
transmit a dominant bit (resynchronization). The BTL
also provides programmable time segments to compensate for the propagation delay time, phase shifts,
and to define the position of the Sample Point within the
bit time. The programming of the BTL depends upon
the baud rate and external physical delay times.
CAN PROTOCOL ENGINE BLOCK DIAGRAM
RX
Bit Timing Logic
Transmit Logic
TX
SAM
Receive
Error Counter
Sample<2:0>
REC
TEC
StuffReg<5:0>
Transmit
Error Counter
Majority
Decision
ErrPas
BusOff
BusMon
Comparator
CRC<14:0>
Protocol
FSM
Comparator
Shift<14:0>
(Transmit<5:0>, Receive<7:0>)
Receive<7:0>
Transmit<7:0>
RecData<7:0>
TrmData<7:0>
Interface to Standard Buffer
DS21291F-page 6
Rec/Trm Addr.
© 2007 Microchip Technology Inc.
MCP2510
2.0
CAN MESSAGE FRAMES
The MCP2510 supports Standard Data Frames,
Extended Data Frames, and Remote Frames (Standard and Extended) as defined in the CAN 2.0B specification.
2.1
Standard Data Frame
The CAN Standard Data Frame is shown in Figure 2-1.
In common with all other frames, the frame begins with
a Start Of Frame (SOF) bit, which is of the dominant
state, which allows hard synchronization of all nodes.
The SOF is followed by the arbitration field, consisting
of 12 bits; the 11-bit ldentifier and the Remote Transmission Request (RTR) bit. The RTR bit is used to distinguish a data frame (RTR bit dominant) from a remote
frame (RTR bit recessive).
Following the arbitration field is the control field, consisting of six bits. The first bit of this field is the Identifier
Extension (IDE) bit which must be dominant to specify
a standard frame. The following bit, Reserved Bit Zero
(RB0), is reserved and is defined to be a dominant bit
by the can protocol. the remaining four bits of the control field are the Data Length Code (DLC) which specifies the number of bytes of data contained in the
message.
After the control field is the data field, which contains
any data bytes that are being sent, and is of the length
defined by the DLC above (0-8 bytes).
The Cyclic Redundancy Check (CRC) Field follows the
data field and is used to detect transmission errors. The
CRC Field consists of a 15-bit CRC sequence, followed
by the recessive CRC Delimiter bit.
The final field is the two-bit acknowledge field. During
the ACK Slot bit, the transmitting node sends out a
recessive bit. Any node that has received an error free
frame acknowledges the correct reception of the frame
by sending back a dominant bit (regardless of whether
the node is configured to accept that specific message
or not). The recessive acknowledge delimiter completes the acknowledge field and may not be overwritten by a dominant bit.
2.2
Extended Data Frame
In the Extended CAN Data Frame, the SOF bit is followed by the arbitration field which consists of 32 bits,
as shown in Figure 2-2. The first 11 bits are the most
significant bits (Base-lD) of the 29-bit identifier. These
11 bits are followed by the Substitute Remote Request
(SRR) bit which is defined to be recessive. The SRR bit
is followed by the lDE bit which is recessive to denote
an extended CAN frame.
It should be noted that if arbitration remains unresolved
after transmission of the first 11 bits of the identifier, and
one of the nodes involved in the arbitration is sending
a standard CAN frame (11-bit identifier), then the stan-
© 2007 Microchip Technology Inc.
dard CAN frame will win arbitration due to the assertion
of a dominant lDE bit. Also, the SRR bit in an extended
CAN frame must be recessive to allow the assertion of
a dominant RTR bit by a node that is sending a standard CAN remote frame.
The SRR and lDE bits are followed by the remaining 18
bits of the identifier (Extended lD) and the remote transmission request bit.
To enable standard and extended frames to be sent
across a shared network, it is necessary to split the 29bit extended message identifier into 11-bit (most significant) and 18-bit (least significant) sections. This split
ensures that the lDE bit can remain at the same bit
position in both standard and extended frames.
Following the arbitration field is the six-bit control field.
the first two bits of this field are reserved and must be
dominant. the remaining four bits of the control field are
the Data Length Code (DLC) which specifies the number of data bytes contained in the message.
The remaining portion of the frame (data field, CRC
field, acknowledge field, end of frame and lntermission)
is constructed in the same way as for a standard data
frame (see Section 2.1).
2.3
Remote Frame
Normally, data transmission is performed on an autonomous basis by the data source node (e.g. a sensor
sending out a data frame). It is possible, however, for a
destination node to request data from the source. To
accomplish this, the destination node sends a remote
frame with an identifier that matches the identifier of the
required data frame. The appropriate data source node
will then send a data frame in response to the remote
frame request.
There are two differences between a remote frame
(shown in Figure 2-3) and a data frame. First, the RTR
bit is at the recessive state, and second, there is no
data field. In the event of a data frame and a remote
frame with the same identifier being transmitted at the
same time, the data frame wins arbitration due to the
dominant RTR bit following the identifier. In this way,
the node that transmitted the remote frame receives
the desired data immediately.
2.4
Error Frame
An Error Frame is generated by any node that detects
a bus error. An error frame, shown in Figure 2-4, consists of two fields, an error flag field followed by an error
delimiter field. There are two types of error flag fields.
Which type of error flag field is sent depends upon the
error status of the node that detects and generates the
error flag field.
If an error-active node detects a bus error then the
node interrupts transmission of the current message by
generating an active error flag. The active error flag is
composed of six consecutive dominant bits. This bit
DS21291F-page 7
MCP2510
sequence actively violates the bit stuffing rule. All other
stations recognize the resulting bit stuffing error and in
turn generate error frames themselves, called error
echo flags. The error flag field, therefore, consists of
between six and twelve consecutive dominant bits
(generated by one or more nodes). The error delimiter
field completes the error frame. After completion of the
error frame, bus activity returns to normal and the interrupted node attempts to resend the aborted message.
If an error-passive node detects a bus error then the
node transmits an error-passive flag followed by the
error delimiter field. The error-passive flag consists of
six consecutive recessive bits, and the error frame for
an error-passive node consists of 14 recessive bits.
From this, it follows that unless the bus error is
detected by the node that is actually transmitting, the
transmission of an error frame by an error-passive
node will not affect any other node on the network. If
the transmitting node generates an error-passive flag
then this will cause other nodes to generate error
frames due to the resulting bit stuffing violation. After
transmission of an error frame, an error-passive node
must wait for six consecutive recessive bits on the bus
before attempting to rejoin bus communications.
The error delimiter consists of eight recessive bits and
allows the bus nodes to restart bus communications
cleanly after an error has occurred.
DS21291F-page 8
2.5
Overload Frame
An Overload Frame, shown in Figure 2-5, has the
same format as an active error frame. An overload
frame, however can only be generated during an lnterframe space. In this way an overload frame can be differentiated from an error frame (an error frame is sent
during the transmission of a message). The overload
frame consists of two fields, an overload flag followed
by an overload delimiter. The overload flag consists of
six dominant bits followed by overload flags generated
by other nodes (and, as for an active error flag, giving
a maximum of twelve dominant bits). The overload
delimiter consists of eight recessive bits. An overload
frame can be generated by a node as a result of two
conditions. First, the node detects a dominant bit during
the interframe space which is an illegal condition. Second, due to internal conditions the node is not yet able
to start reception of the next message. A node may
generate a maximum of two sequential overload
frames to delay the start of the next message.
2.6
Interframe Space
The lnterframe Space separates a preceeding frame
(of any type) from a subsequent data or remote frame.
The interframe space is composed of at least three
recessive bits called the Intermission. This is provided
to allow nodes time for internal processing before the
start of the next message frame. After the intermission,
the bus line remains in the recessive state (bus idle)
until the next transmission starts.
© 2007 Microchip Technology Inc.
© 2007 Microchip Technology Inc.
FIGURE 2-1:
STANDARD DATA FRAME
Identifier
Message
Filtering
7
15
CRC
CRC Del
Ack Slot Bit
ACK Del
16
CRC Field
8
0 0 0
Reserved Bit
0
8
DLC0
11
8N (0≤N≤8)
Data Field
6
Control
Field
4
ID0
RTR
IDE
RB0
DLC3
12
Arbitration Field
ID3
Start of Frame
ID 10
Data Frame (number of bits = 44 + 8N)
1
End of
Frame
IFS
1 1 1 1 1 1 1 1 1 1 1
Data
Length
Code
Stored in Transmit/Receive Buffers
Stored in Buffers
Bit Stuffing
MCP2510
DS21291F-page 9
© 2007 Microchip Technology Inc.
FIGURE 2-2:
EXTENDED DATA FRAME
Data Frame (number of bits = 64 + 8N)
18
EID0
RTR
RB1
RB0
DLC3
11
000
Extended Identifier
Message
Filtering
Stored in Buffers
Reserved bits
Identifier
ID0
SRR
IDE
EID17
0
8
4
DLC0
11
16
CRC Field
8N (0≤N≤8)
Data Field
8
15
CRC
7
CRC Del
Ack Slot Bit
ACK Del
6
Control
Field
Arbitration Field
ID3
Start of Frame
ID10
32
1
End of
Frame
IFS
11111111111
Data
Length
Code
Stored in Transmit/Receive Buffers
Bit Stuffing
MCP2510
DS21291F-page 10
REMOTE DATA FRAME
Identifier
11
100
Extended Identifier
Message
Filtering
DLC0
EID0
RTR
RB1
RB0
DLC3
4
ID0
SRR
IDE
EID17
0
15
CRC
7
CRC Del
Ack Slot Bit
ACK Del
18
ID3
Start of Frame
ID10
Arbitration Field
11
16
CRC Field
6
Control
Field
32
Reserved bits
© 2007 Microchip Technology Inc.
FIGURE 2-3:
1
End of
Frame
IFS
11111111 111
Data
Length
Code
Remote Data Frame with Extended Identifier
MCP2510
DS21291F-page 11
ERROR DATA FRAME
Interrupted Data Frame
0
8N (0≤N≤8)
Data Field
8
8
DLC0
11
6
Control
Field
4
ID0
RTR
IDE
RB0
DLC3
12
Arbitration Field
ID3
Start of Frame
ID 10
© 2007 Microchip Technology Inc.
FIGURE 2-4:
0 0 0
Message
Filtering
Reserved Bit
Identifier
Data
Length
Code
Error Frame
Bit Stuffing
Data Frame or
Remote Frame
6
≤6
8
Error
Flag
Echo
Error
Flag
Error
Delimiter
0 0 1 1 1 1 1 1 1 1 0
DS21291F-page 12
MCP2510
0 0 0 0 0 0 0
Inter-Frame Space or
Overload Frame
© 2007 Microchip Technology Inc.
FIGURE 2-5:
OVERLOAD FRAME
0
1 0 0
7
16
CRC Field
15
CRC
CRC Del
Ack Slot Bit
ACK Del
11
6
Control
Field
4
DLC0
12
Arbitration Field
ID0
RTR
IDE
RB0
DLC3
Start of Frame
ID 10
Remote Frame (number of bits = 44)
1
End of
Frame
1 1 1 1 1 1 1 1
Overload Frame
End of Frame or
Error Delimiter or
Overload Delimiter
6
8
Overload
Flag
Overload
Delimiter
Inter-Frame Space or
Error Frame
0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
MCP2510
DS21291F-page 13
MCP2510
NOTES:
DS21291F-page 14
© 2007 Microchip Technology Inc.
MCP2510
3.0
MESSAGE TRANSMISSION
3.1
Transmit Buffers
The MCP2510 implements three Transmit Buffers.
Each of these buffers occupies 14 bytes of SRAM and
are mapped into the device memory maps. The first
byte, TXBNCTRL, is a control register associated with
the message buffer. The information in this register
determines the conditions under which the message
will be transmitted and indicates the status of the message transmission. (see Register 3-2). Five bytes are
used to hold the standard and extended identifiers and
other message arbitration information (see Register 33 through Register 3-8). The last eight bytes are for the
eight possible data bytes of the message to be transmitted (see Register 3-8).
For the MCU to have write access to the message
buffer, the TXBNCTRL.TXREQ bit must be clear, indicating that the message buffer is clear of any pending
message to be transmitted. At a minimum, the TXBNSIDH, TXBNSIDL, and TXBNDLC registers must be
loaded. If data bytes are present in the message, the
TXBNDm registers must also be loaded. If the message
is to use extended identifiers, the TXBNEIDm registers
must also be loaded and the TXBNSIDL.EXIDE bit set.
Prior to sending the message, the MCU must initialize
the CANINTE.TXINE bit to enable or disable the generation of an interrupt when the message is sent. The
MCU must also initialize the TXBNCTRL.TXP priority
bits (see Section 3.2).
3.2
Transmit Priority
Transmit priority is a prioritization, within the MCP2510,
of the pending transmittable messages. This is independent from, and not necessarily related to, any prioritization implicit in the message arbitration scheme built
into the CAN protocol. Prior to sending the SOF, the priority of all buffers that are queued for transmission is
compared. The transmit buffer with the highest priority
will be sent first. For example, if transmit buffer 0 has a
higher priority setting than transmit buffer 1, buffer 0 will
be sent first. If two buffers have the same priority setting, the buffer with the highest buffer number will be
sent first. For example, if transmit buffer 1 has the same
priority setting as transmit buffer 0, buffer 1 will be sent
first. There are four levels of transmit priority. If TXBNCTRL.TXP<1:0> for a particular message buffer is set to
11, that buffer has the highest possible priority. If
TXBNCTRL.TXP<1:0> for a particular message buffer
is 00, that buffer has the lowest possible priority.
3.3
Initiating Transmission
To initiate message transmission the TXBNCTRL.TXREQ bit must be set for each buffer to be transmitted. This can be done by writing to the register via
the SPI interface or by setting the TXNRTS pin low for
the particular transmit buffer(s) that are to be transmit-
© 2007 Microchip Technology Inc.
ted. If transmission is initiated via the SPI interface, the
TXREQ bit can be set at the same time as the TXP priority bits.
is
set,
When
TXBNCTRL.TXREQ
TXBNCTRL.MLOA
TXBNCTRL.ABTF,
TXBNCTRL.TXERR bits will be cleared.
the
and
Setting the TXBNCTRL.TXREQ bit does not initiate a
message transmission, it merely flags a message
buffer as ready for transmission. Transmission will start
when the device detects that the bus is available. The
device will then begin transmission of the highest priority message that is ready.
When the transmission has completed successfully the
TXBNCTRL.TXREQ bit will be cleared, the CANINTF.TXNIF bit will be set, and an interrupt will be generated if the CANINTE.TXNIE bit is set.
If the message transmission fails, the TXBNCTRL.TXREQ will remain set indicating that the message is still pending for transmission and one of the
following condition flags will be set. If the message
started to transmit but encountered an error condition,
the TXBNCTRL. TXERR and the CANINTF.MERRF
bits will be set and an interrupt will be generated on the
INT pin if the CANINTE.MERRE bit is set. If the message lost arbitration the TXBNCTRL.MLOA bit will be
set.
3.4
TXnRTS Pins
The TXNRTS Pins are input pins that can be configured
as request-to-send inputs, which provides a secondary
means of initiating the transmission of a message from
any of the transmit buffers, or as standard digital inputs.
Configuration and control of these pins is accomplished
using the TXRTSCTRL register (see Register 3-2). The
TXRTSCTRL register can only be modified when the
MCP2510 is in configuration mode (see Section 9.0). If
configured to operate as a request to send pin, the pin
is mapped into the respective TXBNCTRL.TXREQ bit
for the transmit buffer. The TXREQ bit is latched by the
falling edge of the TXNRTS pin. The TXNRTS pins are
designed to allow them to be tied directly to the RXNBF
pins to automatically initiate a message transmission
when the RXNBF pin goes low. The TXNRTS pins have
internal pullup resistors of 100 kΩ (nominal).
3.5
Aborting Transmission
The MCU can request to abort a message in a specific
message buffer by clearing the associated TXBnCTRL.TXREQ bit. Also, all pending messages can be
requested to be aborted by setting the CANCTRL.ABAT bit. If the CANCTRL.ABAT bit is set to
abort all pending messages, the user MUST reset this
bit (typically after the user verifies that all TXREQ bits
have been cleared) to continue trasmit messages. The
CANCTRL.ABTF flag will only be set if the abort was
requested via the CANCTRL.ABAT bit. Aborting a message by resetting the TXREQ bit does cause the ATBF
bit to be set.
DS21291F-page 15
MCP2510
Only messages that have not already begun to be
transmitted can be aborted. Once a message has
begun transmission, it will not be possible for the user
to reset the TXBnCTRL.TXREQ bit. After transmission
FIGURE 3-1:
of a message has begun, if an error occurs on the bus
or if the message loses arbitration, the message will be
retransmitted regardless of a request to abort.
TRANSMIT MESSAGE FLOWCHART
Start
No
The message transmission
sequence begins when the
device determines that the
TXBnCTRL.TXREQ for any of
the transmit registers has been
set.
Are any
TXBnCTRL.TXREQ
bits = 1
?
Yes
Clearing the TxBnCTRL.TXREQ
bit while it is set, or setting the
CANCTRL.ABAT bit before the
message has started transmission
will abort the message.
Clear:
TXBnCTRL.ABTF
TXBnCTRL.MLOA
TXBnCTRL.TXERR
Is
CAN Bus available
to start transmission
?
No
is
TXBnCTRL.TXREQ=0
CANCTRL.ABAT=1
?
Yes
No
Yes
Examine TXBnCTRL.TXP <1:0> to
Determine Highest Priority Message
Transmit Message
Was
Message Transmitted
Successfully?
No
Did
a message error
occur?
Yes
Set
TxBnCTRL.TXERR=1
No
Yes
Set TxBnCTRL.TXREQ=0
Was
Arbitration lost during
transmission?
Yes
Generate
Interrupt
Yes
TxBnCTRL.MLOA=1
CANINTE.TXnIE=1?
No
No
Set
CANTINF.TXnIF=1
The CANINTE.TXnIE bit
determines if an interrupt
should be generated when
a message is successfully
transmitted.
GOTO START
DS21291F-page 16
© 2007 Microchip Technology Inc.
MCP2510
REGISTER 3-1:
TXBNCTRL Transmit Buffer N Control Register
(ADDRESS: 30h, 40h, 50h)
U-0
R-0
R-0
R-0
R/W-0
U-0
R/W-0
R/W-0
—
ABTF
MLOA
TXERR
TXREQ
—
TXP1
TXP0
bit 7
bit 0
bit 7
Unimplemented: Read as '0'
bit 6
ABTF: Message Aborted Flag
1 = Message was aborted
0 = Message completed transmission successfully
bit 5
MLOA: Message Lost Arbitration
1 = Message lost arbitration while being sent
0 = Message did not lose arbitration while being sent
bit 4
TXERR: Transmission Error Detected
1 = A bus error occurred while the message was being transmitted
0 = No bus error occurred while the message was being transmitted
bit 3
TXREQ: Message Transmit Request
1 = Buffer is currently pending transmission
(MCU sets this bit to request message be transmitted - bit is automatically cleared when
the message is sent)
0 = Buffer is not currently pending transmission
(MCU can clear this bit to request a message abort)
bit 2
Unimplemented: Read as '0'
bit 1-0
TXP<1:0>: Transmit Buffer Priority
11 = Highest Message Priority
10 = High Intermediate Message Priority
11 = Low Intermediate Message Priority
00 = Lowest Message Priority
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
© 2007 Microchip Technology Inc.
x = Bit is unknown
DS21291F-page 17
MCP2510
REGISTER 3-2:
TXRTSCTRL - TXNRTS PIN CONTROL AND STATUS REGISTER
(ADDRESS: 0Dh)
U-0
U-0
R-x
R-x
R-x
R/W-0
—
—
B2RTS
B1RTS
B0RTS
B2RTSM
R/W-0
R/W-0
B1RTSM B0RTSM
bit 7
bit 0
bit 7
Unimplemented: Read as '0'
bit 6
Unimplemented: Read as '0'
bit 5
B2RTS: TX2RTS Pin State
- Reads state of TX2RTS pin when in digital input mode
- Reads as ‘0’ when pin is in ‘request to send’ mode
bit 4
B1RTS: TX1RTX Pin State
- Reads state of TX1RTS pin when in digital input mode
- Reads as ‘0’ when pin is in ‘request to send’ mode
bit 3
B0RTS: TX0RTS Pin State
- Reads state of TX0RTS pin when in digital input mode
- Reads as ‘0’ when pin is in ‘request to send’ mode
bit 2
B2RTSM: TX2RTS Pin Mode
1 = Pin is used to request message transmission of TXB2 buffer (on falling edge)
0 = Digital input
bit 1
B1RTSM: TX1RTS Pin Mode
1 = Pin is used to request message transmission of TXB1 buffer (on falling edge)
0 = Digital input
bit 0
B0RTSM: TX0RTS Pin Mode
1 = Pin is used to request message transmission of TXB0 buffer (on falling edge)
0 = Digital input
Legend:
REGISTER 3-3:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
TXBNSIDH - TRANSMIT BUFFER N STANDARD IDENTIFIER HIGH
(ADDRESS: 31h, 41h, 51h)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
bit 7
bit 7-0
bit 0
SID<10:3>: Standard Identifier Bits <10:3>
Legend:
DS21291F-page 18
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
© 2007 Microchip Technology Inc.
MCP2510
REGISTER 3-4:
TXBNSIDL - Transmit Buffer N Standard Identifier Low
(ADDRESS: 32h, 42h, 52h)
R/W-x
SID2
R/W-x
SID1
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
SID0
—
EXIDE
—
EID17
EID16
bit 7
bit 0
bit 7-5
SID<2:0>: Standard Identifier Bits <2:0>
bit 4
Unimplemented: Reads as '0’
bit 3
EXIDE: Extended Identifier Enable
1 = Message will transmit extended identifier
0 = Message will transmit standard identifier
bit 2
Unimplemented: Reads as '0’
bit 1-0
EID<17:16>: Extended Identifier Bits <17:16>
Legend:
REGISTER 3-5:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
TXBNEID8 - TRANSMIT BUFFER N EXTENDED IDENTIFIER HIGH
(ADDRESS: 33h, 43h, 53h)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
bit 7
bit 7-0
bit 0
EID<15:8>: Extended Identifier Bits <15:8>
Legend:
REGISTER 3-6:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
TXBNEID0 - TRANSMIT BUFFER N EXTENDED IDENTIFIER LOW
(ADDRESS: 34h, 44h, 54h)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
bit 7
bit 7-0
bit 0
EID<7:0>: Extended Identifier Bits <7:0>
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
© 2007 Microchip Technology Inc.
x = Bit is unknown
DS21291F-page 19
MCP2510
REGISTER 3-7:
TXBNDLC - Transmit Buffer N Data Length Code
(ADDRESS: 35h, 45h, 55h)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
—
RTR
—
—
DLC3
DLC2
DLC1
DLC0
bit 7
bit 0
bit 7
Unimplemented: Reads as '0’
bit 6
RTR: Remote Transmission Request Bit
1 = Transmitted Message will be a Remote Transmit Request
0 = Transmitted Message will be a Data Frame
bit 5-4
Unimplemented: Reads as '0’
bit 3-0
DLC<3:0>: Data Length Code
Sets the number of data bytes to be transmitted (0 to 8 bytes)
Note:
It is possible to set the DLC to a value greater than 8, however only 8 bytes are transmitted
Legend:
REGISTER 3-8:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
TXBNDM - Transmit Buffer N Data Field Byte m
(ADDRESS: 36h-3Dh, 46h-4Dh, 56h-5Dh)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
TXBNDm
7
TXBNDm
6
TXBNDm
5
TXBNDm
4
TXBNDm
3
TXBNDm
2
TXBNDm
1
TXBNDm
0
bit 7
bit 7-0
bit 0
TXBNDM7:TXBNDM0: Transmit Buffer N Data Field Byte m
Legend:
DS21291F-page 20
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
© 2007 Microchip Technology Inc.
MCP2510
4.0
MESSAGE RECEPTION
4.1
Receive Message Buffering
The MCP2510 includes two full receive buffers with
multiple acceptance filters for each. There is also a
separate Message Assembly Buffer (MAB) which acts
as a third receive buffer (see Figure 4-1).
4.2
Receive Buffers
Of the three Receive Buffers, the MAB is always committed to receiving the next message from the bus. The
remaining two receive buffers are called RXB0 and
RXB1 and can receive a complete message from the
protocol engine. The MCU can access one buffer while
the other buffer is available for message reception or
holding a previously received message.
The MAB assembles all messages received. These
messages will be transferred to the RXBN buffers (See
Register 4-4 to Register 4-9) only if the acceptance filter criteria are met.
Note:
The entire contents of the MAB is moved
into the receive buffer once a message is
accepted. This means that regardless of
the type of identifier (standard or extended)
and the number of data bytes received, the
entire receive buffer is overwritten with the
MAB contents. Therefore the contents of
all registers in the buffer must be assumed
to have been modified when any message
is received.
When a message is moved into either of the receive
buffers the appropriate CANINTF.RXNIF bit is set. This
bit must be cleared by the MCU, when it has completed
processing the message in the buffer, in order to allow
a new message to be received into the buffer. This bit
provides a positive lockout to ensure that the MCU has
finished with the message before the MCP2510
attempts to load a new message into the receive buffer.
If the CANINTE.RXNIE bit is set an interrupt will be generated on the INT pin to indicate that a valid message
has been received.
4.3
Receive Priority
RXB0 is the higher priority buffer and has two message
acceptance filters associated with it. RXB1 is the lower
priority buffer and has four acceptance filters associated with it. The lower number of acceptance filters
makes the match on RXB0 more restrictive and implies
a higher priority for that buffer. Additionally, the
RXB0CTRL register can be configured such that if
RXB0 contains a valid message, and another valid
message is received, an overflow error will not occur
and the new message will be moved into RXB1 regardless of the acceptance criteria of RXB1. There are also
two programmable acceptance filter masks available,
one for each receive buffer (see Section 4.5).
© 2007 Microchip Technology Inc.
When a message is received, bits <3:0> of the RXBNCTRL Register will indicate the acceptance filter number
that enabled reception, and whether the received message is a remote transfer request.
The RXBNCTRL.RXM bits set special receive modes.
Normally, these bits are set to 00 to enable reception of
all valid messages as determined by the appropriate
acceptance filters. In this case, the determination of
whether or not to receive standard or extended messages is determined by the RFXNSIDL.EXIDE bit in the
acceptance filter register. If the RXBNCTRL.RXM bits
are set to 01 or 10, the receiver will accept only messages with standard or extended identifiers respectively. If an acceptance filter has the RFXNSIDL.EXIDE
bit set such that it does not correspond with the
RXBNCTRL.RXM mode, that acceptance filter is rendered useless. These two modes of RXBNCTRL.RXM
bits can be used in systems where it is known that only
standard or extended messages will be on the bus. If
the RXBNCTRL.RXM bits are set to 11, the buffer will
receive all messages regardless of the values of the
acceptance filters. Also, if a message has an error
before the end of frame, that portion of the message
assembled in the MAB before the error frame will be
loaded into the buffer. This mode has some value in
debugging a CAN system and would not be used in an
actual system environment.
4.4
RX0BF and RX1BF Pins
In addition to the INT pin which provides an interrupt
signal to the MCU for many different conditions, the
receive buffer full pins (RX0BF and RX1BF) can be
used to indicate that a valid message has been loaded
into RXB0 or RXB1, respectively.
The RXBNBF full pins can be configured to act as buffer
full interrupt pins or as standard digital outputs. Configuration and status of these pins is available via the
BFPCTRL register (Register 4-3). When set to operate
in interrupt mode (by setting BFPCTRL.BxBFE and
BFPCTRL.BxBFM bits to a 1), these pins are active low
and are mapped to the CANINTF.RXNIF bit for each
receive buffer. When this bit goes high for one of the
receive buffers, indicating that a valid message has
been loaded into the buffer, the corresponding RXNBF
pin will go low. When the CANINTF.RXNIF bit is cleared
by the MCU, then the corresponding interrupt pin will
go to the logic high state until the next message is
loaded into the receive buffer.
When used as digital outputs, the BFPCTRL.BxBFM
bits must be cleared to a ‘0’ and BFPCTRL.BxBFE bits
must be set to a ‘1’ for the associated buffer. In this
mode the state of the pin is controlled by the BFPCTRL.BxBFS bits. Writting a ‘1’ to the BxBFS bit will
cause a high level to be driven on the assicated buffer
full pin, and a ‘0’ will cause the pin to drive low. When
using the pins in this mode the state of the pin should
be modified only by using the Bit Modify SPI command
to prevent glitches from occuring on either of the buffer
full pins.
DS21291F-page 21
MCP2510
FIGURE 4-1:
RECEIVE BUFFER BLOCK DIAGRAM
Acceptance Mask
RXM1
Acceptance Filter
RXF2
Acceptance Mask
RXM0
A
c
c
e
p
t
R
X
B
0
Acceptance Filter
RXF0
Acceptance Filter
RXF4
Acceptance Filter
RXF1
Acceptance Filter
RXF5
Identifier
Data Field
DS21291F-page 22
Acceptance Filter
RXF3
M
A
B
Identifier
A
c
c
e
p
t
R
X
B
1
Data Field
© 2007 Microchip Technology Inc.
MCP2510
FIGURE 4-2:
MESSAGE RECEPTION FLOWCHART
Start
Detect
Start of
Message
?
No
Yes
Begin Loading Message into
Message Assembly Buffer (MAB)
Generate
Error
Frame
Valid
Message
Received
?
No
Yes
Yes, meets criteria
Yes, meets criteria
Message
for RXB1
for RXBO
Identifier meets
a filter criteria
?
No
Go to Start
The CANINTF.RXnIF bit
determines if the receive
register is empty and able
to accept a new message
The RXB0CTRL.BUKT
bit determines if RXB0
can roll over into RXB1
if it is full
Is
CANINTF.RX0IF=0
?
No
Is
Yes
RXB0CTRL.BUKT=1
?
No
Yes
Move message into RXB0
Is
Generate Overflow Error: No
CANINTF.RX1IF = 0
Set EFLG.RX1OVR
?
Generate Overflow Error:
Set EFLG.RX0OVR
Set CANINTF.RX0IF=1
Yes
Move message into RXB1
Is
No
CANINTE.ERRIE=1
?
Set RXB0CTRL.FILHIT <0>
according to which filter criteria
Set CANINTF.RX1IF=1
Yes
Set RXB0CTRL.FILHIT <2:0>
according to which filter criteria
was met
Go to Start
CANINTE.RX0IE=1?
Yes
No
ARE
BFPCTRL.B0BFM=1
AND
BF1CTRL.B0BFE=1
?
No
© 2007 Microchip Technology Inc.
Yes
Generate
Interrupt on INT
RXB0
Set CANSTAT <3:0> according to which receive buffer
the message was loaded into
RXB1
No
Yes
Yes
Set RXBF0
Pin = 0
Set RXBF1
Pin = 0
CANINTE.RX1IE=1?
ARE
BFPCTRL.B1BFM=1
AND
BF1CTRL.B1BFE=1
?
No
DS21291F-page 23
MCP2510
REGISTER 4-1:
RXB0CTRL - RECEIVE BUFFER 0 CONTROL REGISTER
(ADDRESS: 60h)
U-0
R/W-0
R/W-0
U-0
R-0
R/W-0
R-0
R-0
—
RXM1
RXM0
—
RXRTR
BUKT
BUKT1
FILHIT0
bit 7
bit 0
bit 7
Unimplemented: Read as '0'
bit 6-5
RXM<1:0>: Receive Buffer Operating Mode
11 =Turn mask/filters off; receive any message
10 =Receive only valid messages with extended identifiers that meet filter criteria
01 =Receive only valid messages with standard identifiers that meet filter criteria
00 =Receive all valid messages using either standard or extended identifiers that meet filter
criteria
bit 4
Unimplemented: Read as '0'
bit 3
RXRTR: Received Remote Transfer Request
1 = Remote Transfer Request Received
0 = No Remote Transfer Request Received
bit 2
BUKT: Rollover Enable
1 = RXB0 message will rollover and be written to RXB1 if RXB0 is full
0 = Rollover disabled
bit 1
BUKT1: Read Only Copy of BUKT Bit (used internally by the MCP2510).
bit 0
FILHIT<0>: Filter Hit - indicates which acceptance filter enabled reception of message
1 = Acceptance Filter 1 (RXF1)
0 = Acceptance Filter 0 (RXF0)
Note:
If a rollover from RXB0 to RXB1 occurs, the FILHIT bit will reflect the filter that accepted
the message that rolled over
Legend:
DS21291F-page 24
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
© 2007 Microchip Technology Inc.
MCP2510
REGISTER 4-2:
RXB1CTRL - RECEIVE BUFFER 1 CONTROL REGISTER
(ADDRESS: 70h)
U-0
R/W-0
R/W-0
U-0
R-0
R-0
R-0
R-0
—
RXM1
RXM0
—
RXRTR
FILHIT2
FILHIT1
FILHIT0
bit 7
bit 0
bit 7
Unimplemented: Read as '0'
bit 6-5
RXM<1:0>: Receive Buffer Operating Mode
11 =Turn mask/filters off; receive any message
10 =Receive only valid messages with extended identifiers that meet filter criteria
01 =Receive only valid messages with standard identifiers that meet filter criteria
00 =Receive all valid messages using either standard or extended identifiers that meet filter
criteria
bit 4
Unimplemented: Read as '0'
bit 3
RXRTR: Received Remote Transfer Request
1 = Remote Transfer Request Received
0 = No Remote Transfer Request Received
bit 2-0
FILHIT<2:0>: Filter Hit - indicates which acceptance filter enabled reception of message
101 = Acceptance Filter 5 (RXF5)
100 = Acceptance Filter 4 (RXF4)
011 = Acceptance Filter 3 (RXF3)
010 = Acceptance Filter 2 (RXF2)
001 = Acceptance Filter 1 (RXF1) (Only if BUKT bit set in RXB0CTRL)
000 = Acceptance Filter 0 (RXF0) (Only if BUKT bit set in RXB0CTRL)
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
© 2007 Microchip Technology Inc.
x = Bit is unknown
DS21291F-page 25
MCP2510
REGISTER 4-3:
BFPCTRL - RXNBF PIN CONTROL AND STATUS REGISTER
(ADDRESS: 0Ch)
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
—
—
B1BFS
B0BFS
B1BFE
B0BFE
B1BFM
B0BFM
bit 7
bit 0
bit 7
Unimplemented: Read as '0'
bit 6
Unimplemented: Read as '0'
bit 5
B1BFS: RX1BF Pin State (digital output mode only)
- Reads as ‘0’ when RX1BF is configured as interrupt pin
bit 4
B0BFS: RX0BF Pin State (digital output mode only)
- Reads as ‘0’ when RX0BF is configured as interrupt pin
bit 3
B1BFE: RX1BF Pin Function Enable
1 = Pin function enabled, operation mode determined by B1BFM bit
0 = Pin function disabled, pin goes to high impedance state
bit 2
B0BFE: RX0BF Pin Function Enable
1 = Pin function enabled, operation mode determined by B0BFM bit
0 = Pin Function disabled, pin goes to high impedance state
bit 1
B1BFM: RX1BF Pin Operation Mode
1 = Pin is used as interrupt when valid message loaded into RXB1
0 = Digital output mode
bit 0
B0BFM: RX0BF Pin Operation Mode
1 = Pin is used as interrupt when valid message loaded into RXB0
0 = Digital output mode
Legend:
REGISTER 4-4:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
RXBNSIDH - RECEIVE BUFFER N STANDARD IDENTIFIER HIGH
(ADDRESS: 61h, 71h)
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
bit 7
bit 7-0
bit 0
SID<10:3>: Standard Identifier Bits <10:3>
These bits contain the eight most significant bits of the Standard Identifier for the received message
Legend:
DS21291F-page 26
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
© 2007 Microchip Technology Inc.
MCP2510
REGISTER 4-5:
RXBNSIDL - RECEIVE BUFFER N STANDARD IDENTIFIER LOW
(ADDRESS: 62h, 72h)
R-x
SID2
R-x
SID1
R-x
SID0
R-x
SRR
R-x
U-0
R-x
R-x
IDE
—
EID17
EID16
bit 7
bit 0
bit 7-5
SID<2:0>: Standard Identifier Bits <2:0>
These bits contain the three least significant bits of the Standard Identifier for the received message
bit 4
SRR: Standard Frame Remote Transmit Request Bit (valid only if IDE bit = ‘0’)
1 = Standard Frame Remote Transmit Request Received
0 = Standard Data Frame Received
bit 3
IDE: Extended Identifier Flag
This bit indicates whether the received message was a Standard or an Extended Frame
1 = Received message was an Extended Frame
0 = Received message was a Standard Frame
bit 2
Unimplemented: Reads as '0'
bit 1-0
EID<17:16>: Extended Identifier Bits <17:16>
These bits contain the two most significant bits of the Extended Identifier for the received message
Legend:
REGISTER 4-6:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
RXBNEID8 - RECEIVE BUFFER N EXTENDED IDENTIFIER MID
(ADDRESS: 63h, 73h)
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
bit 7
bit 7-0
bit 0
EID<15:8>: Extended Identifier Bits <15:8>
These bits hold bits 15 through 8 of the Extended Identifier for the received message
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
© 2007 Microchip Technology Inc.
x = Bit is unknown
DS21291F-page 27
MCP2510
REGISTER 4-7:
RXBNEID0 - RECEIVE BUFFER N EXTENDED IDENTIFIER LOW
(ADDRESS: 64h, 74h)
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
bit 7
bit 7-0
bit 0
EID<7:0>: Extended Identifier Bits <7:0>
These bits hold the least significant eight bits of the Extended Identifier for the received message
Legend:
REGISTER 4-8:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
RXBNDLC - RECEIVE BUFFER N DATA LENGTH CODE
(ADDRESS: 65h, 75h)
U-0
R-x
R-x
R-x
R-x
R-x
R-x
R-x
—
RTR
RB1
RB0
DLC3
DLC2
DLC1
DLC0
bit 7
bit 0
bit 7
Unimplemented: Reads as '0'
bit 6
RTR: Extended Frame Remote Transmission Request Bit (valid only when RXBnSIDL.IDE = 1)
1 = Extended Frame Remote Transmit Request Received
0 = Extended Data Frame Received
bit 5
RB1: Reserved Bit 1
bit 4
RB0: Reserved Bit 0
bit 3-0
DLC<3:0>: Data Length Code
Indicates number of data bytes that were received
Legend:
REGISTER 4-9:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
RXBNDM - RECEIVE BUFFER N DATA FIELD BYTE M
(ADDRESS: 66h-6Dh, 76h-7Dh)
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
RBNDm7
RBNDm6
RBNDm5
RBNDm4
RBNDm3
RBNDm2
RBNDm1
RBNDm0
bit 7
bit 7-0
bit 0
RBNDm7:RBNDm0: Receive Buffer N Data Field Byte m
Eight bytes containing the data bytes for the received message
Legend:
DS21291F-page 28
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
© 2007 Microchip Technology Inc.
MCP2510
4.5
Message Acceptance Filters and
Masks
The Message Acceptance Filters And Masks are used
to determine if a message in the message assembly
buffer should be loaded into either of the receive buffers (see Figure 4-3). Once a valid message has been
received into the MAB, the identifier fields of the message are compared to the filter values. If there is a
match, that message will be loaded into the appropriate
receive buffer. The filter masks (see Register 4-10
through Register 4-17) are used to determine which
bits in the identifier are examined with the filters. A truth
table is shown below in Table 4-1 that indicates how
each bit in the identifier is compared to the masks and
filters to determine if a the message should be loaded
into a receive buffer. The mask essentially determines
which bits to apply the acceptance filters to. If any mask
bit is set to a zero, then that bit will automatically be
accepted regardless of the filter bit.
TABLE 4-1:
FILTER/MASK TRUTH TABLE
Mask Bit
n
Filter Bit
n
Message
Identifier bit
n001
Accept or
reject bit n
0
X
X
Accept
1
0
0
Accept
1
0
1
Reject
1
1
0
Reject
1
1
1
Accept
Note:
Note:
000 and 001 can only occur if the BUKT bit
(see Table 4-1) is set in the RXB0CTRL
register allowing RXB0 messages to roll
over into RXB1.
RXB0CTRL contains two copies of the BUKT bit and
the FILHIT<0> bit.
The coding of the BUKT bit enables these three bits to
be used similarly to the RXB1CTRL.FILHIT bits and to
distinguish a hit on filter RXF0 and RXF1 in either
RXB0 or after a roll over into RXB1.
-
111 = Acceptance Filter 1 (RXF1)
110 = Acceptance Filter 0 (RXF0)
001 = Acceptance Filter 1 (RXF1)
000 = Acceptance Filter 0
If the BUKT bit is clear, there are six codes corresponding to the six filters. If the BUKT bit is set, there are six
codes corresponding to the six filters plus two additional codes corresponding to RXF0 and RXF1 filters
that roll over into RXB1.
If more than one acceptance filter matches, the FILHIT
bits will encode the binary value of the lowest numbered filter that matched. In other words, if filter RXF2
and filter RXF4 match, FILHIT will be loaded with the
value for RXF2. This essentially prioritizes the acceptance filters with a lower number filter having higher priority. Messages are compared to filters in ascending
order of filter number.
The mask and filter registers can only be modified
when the MCP2510 is in configuration mode (see
Section 9.0).
X = don’t care
As shown in the Receive Buffers Block Diagram
(Figure 4-1), acceptance filters RXF0 and RXF1, and
filter mask RXM0 are associated with RXB0. Filters
RXF2, RXF3, RXF4, and RXF5 and mask RXM1 are
associated with RXB1. When a filter matches and a
message is loaded into the receive buffer, the filter
number that enabled the message reception is loaded
into the RXBNCTRL register FILHIT bit(s). For RXB1
the RXB1CTRL register contains the FILHIT<2:0> bits.
They are coded as follows:
-
101 = Acceptance Filter 5 (RXF5)
100 = Acceptance Filter 4 (RXF4)
011 = Acceptance Filter 3 (RXF3)
010 = Acceptance Filter 2 (RXF2)
001 = Acceptance Filter 1 (RXF1)
000 = Acceptance Filter 0 (RXF0)
© 2007 Microchip Technology Inc.
DS21291F-page 29
MCP2510
FIGURE 4-3:
MESSAGE ACCEPTANCE MASK AND FILTER OPERATION
Acceptance Filter Register
RXFn0
Acceptance Mask Register
RXMn0
RXMn1
RXFn1
RXFnn
RxRqst
RXMnn
Message Assembly Buffer
Identifier
REGISTER 4-10:
RXFNSIDH - ACCEPTANCE FILTER N STANDARD IDENTIFIER HIGH
(ADDRESS: 00h, 04h, 08h, 10h, 14h, 18h)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
bit 7
bit 7-0
bit 0
SID<10:3>: Standard Identifier Filter Bits <10:3>
These bits hold the filter bits to be applied to bits <10:3> of the Standard Identifier portion of a
received message
Legend:
DS21291F-page 30
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
© 2007 Microchip Technology Inc.
MCP2510
REGISTER 4-11:
RXFNSIDL - ACCEPTANCE FILTER N STANDARD IDENTIFIER LOW
(ADDRESS: 01h, 05h, 09h, 11h, 15h, 19h)
R/W-x
SID2
R/W-x
SID1
R/W-x
U-0
R/W-x
U-0
R/W-x
R/W-x
SID0
—
EXIDE
—
EID17
EID16
bit 7
bit 0
bit 7-5
SID<2:0>: Standard Identifier Filter Bits <2:0>
These bits hold the filter bits to be applied to bits <2:0> of the Standard Identifier portion of a
received message
bit 4
Unimplemented: Reads as '0'
bit 3
EXIDE: Extended Identifier Enable
1 = Filter is applied only to Extended Frames
0 = Filter is applied only to Standard Frames
bit 2
Unimplemented: Reads as '0
bit 1-0
EID<17:16>: Exended Identifier Filter Bits <17:16>
These bits hold the filter bits to be applied to bits <17:16> of the Extended Identifier portion of
a received message
Legend:
REGISTER 4-12:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
RXFNEID8 - ACCEPTANCE FILTER N EXTENDED IDENTIFIER HIGH
(ADDRESS: 02h, 06h, 0Ah, 12h, 16h, 1Ah)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
bit 7
bit 7-0
bit 0
EID<15:8>: Extended Identifier Bits <15:8>
These bits hold the filter bits to be applied to bits <15:8> of the Extended Identifier portion of a
received message
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
© 2007 Microchip Technology Inc.
x = Bit is unknown
DS21291F-page 31
MCP2510
REGISTER 4-13:
RXFNEID0 - ACCEPTANCE FILTER N EXTENDED IDENTIFIER LOW
(ADDRESS: 03h, 07h, 0Bh, 13h, 17h, 1Bh)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
bit 7
bit 7-0
bit 0
EID<7:0>: Extended Identifier Bits <7:0>
These bits hold the filter bits to be applied to the bits <7:0> of the Extended Identifier portion of
a received message
Legend:
REGISTER 4-14:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
RXMNSIDH - ACCEPTANCE FILTER MASK N STANDARD IDENTIFIER HIGH
(ADDRESS: 20h, 24h)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
bit 7
bit 7-0
bit 0
SID<10:3>: Standard Identifier Mask Bits <10:3>
These bits hold the mask bits to be applied to bits <10:3> of the Standard Identifier portion of a
received message
Legend:
REGISTER 4-15:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
RXMNSIDL - ACCEPTANCE FILTER MASK N STANDARD IDENTIFIER LOW
(ADDRESS: 21h, 25h)
R/W-x
SID2
R/W-x
SID1
R/W-x
U-0
U-0
U-0
R/W-x
R/W-x
SID0
—
—
—
EID17
EID16
bit 7
bit 0
bit 7-5
SID<2:0>: Standard Identifier Mask Bits <2:0>
These bits hold the mask bits to be applied to bits<2:0> of the Standard Identifier portion of a
received message
bit 4-2
Unimplemented: Reads as '0'
bit 1-0
EID<17:16>: Extended Identifier Mask Bits <17:16>
These bits hold the mask bits to be applied to bits <17:16> of the Extended Identifier portion of
a received message
Legend:
DS21291F-page 32
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
© 2007 Microchip Technology Inc.
MCP2510
REGISTER 4-16:
RXMNEID8 - ACCEPTANCE FILTER MASK N EXTENDED IDENTIFIER HIGH
(ADDRESS: 22h, 26h)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
bit 7
bit 7-0
bit 0
EID<15:8>: Extended Identifier Bits <15:8>
These bits hold the filter bits to be applied to bits <15:8> of the Extended Identifier portion of a
received message
Legend:
REGISTER 4-17:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
RXMNEID0 - ACCEPTANCE FILTER MASK N EXTENDED IDENTIFIER LOW
(ADDRESS: 23h, 27h)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
bit 7
bit 7-0
bit 0
EID<7:0>: Extended Identifier Mask Bits <7:0>
These bits hold the mask bits to be applied to the bits <7:0> of the Extended Identifier portion
of a received message
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
© 2007 Microchip Technology Inc.
x = Bit is unknown
DS21291F-page 33
MCP2510
NOTES:
DS21291F-page 34
© 2007 Microchip Technology Inc.
MCP2510
5.0
BIT TIMING
All nodes on a given CAN bus must have the same
nominal bit rate. The CAN protocol uses Non Return to
Zero (NRZ) coding which does not encode a clock
within the data stream. Therefore, the receive clock
must be recovered by the receiving nodes and synchronized to the transmitters clock.
As oscillators and transmission time may vary from
node to node, the receiver must have some type of
Phase Lock Loop (PLL) synchronized to data transmission edges to synchronize and maintain the receiver
clock. Since the data is NRZ coded, it is necessary to
include bit stuffing to ensure that an edge occurs at
least every six bit times, to maintain the Digital Phase
Lock Loop (DPLL) synchronization.
The bit timing of the MCP2510 is implemented using a
DPLL that is configured to synchronize to the incoming
data, and provide the nominal timing for the transmitted
data. The DPLL breaks each bit time into multiple segments made up of minimal periods of time called the
time quanta (TQ).
Bus timing functions executed within the bit time frame,
such as synchronization to the local oscillator, network
transmission delay compensation, and sample point
positioning, are defined by the programmable bit timing
logic of the DPLL.
The nominal bit rate is the number of bits transmitted
per second assuming an ideal transmitter with an ideal
oscillator, in the absence of resynchronization. The
nominal bit rate is defined to be a maximum of 1 Mb/s.
Nominal Bit Time is defined as:
TBIT = 1 / NOMlNAL BlT RATE
The nominal bit time can be thought of as being divided
into separate non-overlapping time segments. These
segments are shown in Figure 5-1.
-
Synchronization Segment (Sync_Seg)
Propagation Time Segment (Prop_Seg)
Phase Buffer Segment 1 (Phase_Seg1)
Phase Buffer Segment 2 [Phase_Seg2)
Nominal Bit Time = TQ * (Sync_Seg + Prop_Seg +
Phase_Seg1 + Phase_Seg2)
The time segments and also the nominal bit time are
made up of integer units of time called time quanta or
TQ (see Figure 5-1). By definition, the nominal bit time
is programmable from a minimum of 8 TQ to a maximum of 25 TQ. Also, by definition the minimum nominal
bit time is 1 µs, corresponding to a maximum 1 Mb/s
rate.
All devices on the CAN bus must use the same bit rate.
However, all devices are not required to have the same
master oscillator clock frequency. For the different
clock frequencies of the individual devices, the bit rate
has to be adjusted by appropriately setting the baud
rate prescaler and number of time quanta in each segment.
FIGURE 5-1:
BIT TIME PARTITIONING
Input Signal
Sync
Prop
Segment
Phase
Segment 1
Phase
Segment 2
Sample Point
TQ
© 2007 Microchip Technology Inc.
DS21291F-page 35
MCP2510
5.1
Time Quanta
The Time Quanta (TQ) is a fixed unit of time derived
from the oscillator period. There is a programmable
baud-rate prescaler, with integral values ranging from 1
to 64, in addition to a fixed divide by two for clock generation.
Time quanta is defined as:
T Q = 2* ( Baud Rate + 1 )*TOSC
where Baud Rate is the binary value represented by
CNF1.BRP<5:0>
For some examples:
If FOSC = 16 MHz, BRP<5:0> = 00h, and Nominal Bit
Time = 8 TQ;
then TQ= 125 nsec and Nominal Bit Rate = 1 Mb/s
If FOSC = 20 MHz, BRP<5:0> = 01h, and Nominal Bit
Time = 8 TQ;
then TQ= 200 nsec and Nominal Bit Rate = 625 Kb/s
If FOSC = 25 MHz, BRP<5:0> = 3Fh, and Nominal Bit
Time = 25 TQ;
then TQ = 5.12 µsec and Nominal Bit Rate = 7.8 Kb/s
The frequencies of the oscillators in the different nodes
must be coordinated in order to provide a system-wide
specified nominal bit time. This means that all oscillators must have a TOSC that is a integral divisor of TQ. It
should also be noted that although the number of TQ is
programmable from 4 to 25, the usable minimum is 6
TQ. Attempting to a bit time of less than 6 TQ in length
is not guaranteed to operate correctly
5.2
Synchronization Segment
This part of the bit time is used to synchronize the various CAN nodes on the bus. The edge of the input signal is expected to occur during the sync segment. The
duration is 1 TQ.
5.3
Propagation Segment
This part of the bit time is used to compensate for physical delay times within the network. These delay times
consist of the signal propagation time on the bus line
and the internal delay time of the nodes. The delay is
calculated as being the round trip time from transmitter
to receiver (twice the signal's propagation time on the
bus line), the input comparator delay, and the output
driver delay. The length of the Propagation Segment
can be programmed from 1 TQ to 8 TQ by setting the
PRSEG2:PRSEG0 bits of the CNF2 register
(Register 5-2).
DS21291F-page 36
The total delay is calculated from the following individual delays:
- 2 * physical bus end to end delay; TBUS
- 2 * input comparator delay; TCOMP (depends
on application circuit)
- 2 * output driver delay; TDRIVE (depends on
application circuit)
- 1 * input to output of CAN controller; TCAN
(maximum defined as 1 TQ + delay ns)
- TPROPOGATION = 2 * (TBUS + TCOMP +
TDRIVE) + TCAN
- Prop_Seg = TPROPOGATION / TQ
5.4
Phase Buffer Segments
The Phase Buffer Segments are used to optimally
locate the sampling point of the received bit within the
nominal bit time. The sampling point occurs between
phase segment 1 and phase segment 2. These segments can be lengthened or shortened by the resynchronization process (see Section 5.7.2). Thus, the
variation of the values of the phase buffer segments
represent the DPLL functionality. The end of phase
segment 1 determines the sampling point within a bit
time. phase segment 1 is programmable from 1 TQ to 8
TQ in duration. Phase segment 2 provides delay before
the next transmitted data transition and is also programmable from 1 TQ to 8 TQ in duration (however due
to IPT requirements the actual minimum length of
phase segment 2 is 2 TQ - see Section 5.6 below), or it
may be defined to be equal to the greater of phase segment 1 or the Information Processing Time (IPT). (see
Section 5.6).
5.5
Sample Point
The Sample Point is the point of time at which the bus
level is read and value of the received bit is determined.
The Sampling point occurs at the end of phase segment 1. If the bit timing is slow and contains many TQ,
it is possible to specify multiple sampling of the bus line
at the sample point. The value of the received bit is
determined to be the value of the majority decision of
three values. The three samples are taken at the sample point, and twice before with a time of TQ/2 between
each sample.
5.6
Information Processing Time
The Information Processing Time (IPT) is the time segment, starting at the sample point, that is reserved for
calculation of the subsequent bit level. The CAN specification defines this time to be less than or equal to 2
TQ. The MCP2510 defines this time to be 2 TQ. Thus,
phase segment 2 must be at least 2 TQ long.
© 2007 Microchip Technology Inc.
MCP2510
5.7
Synchronization
To compensate for phase shifts between the oscillator
frequencies of each of the nodes on the bus, each CAN
controller must be able to synchronize to the relevant
signal edge of the incoming signal. Synchronization is
the process by which the DPLL function is implemented. When an edge in the transmitted data is
detected, the logic will compare the location of the edge
to the expected time (Sync Seg). The circuit will then
adjust the values of phase segment 1 and phase segment 2 as necessary. There are two mechanisms used
for synchronization.
5.7.1
HARD SYNCHRONIZATION
Hard Synchronization is only done when there is a
recessive to dominant edge during a BUS IDLE condition, indicating the start of a message. After hard synchronization, the bit time counters are restarted with
Sync Seg. Hard synchronization forces the edge which
has occurred to lie within the synchronization segment
of the restarted bit time. Due to the rules of synchronization, if a hard synchronization occurs there will not be
a resynchronization within that bit time.
5.7.2
RESYNCHRONIZATION
As a result of Resynchronization, phase segment 1
may be lengthened or phase segment 2 may be shortened. The amount of lengthening or shortening of the
phase buffer segments has an upper bound given by
the Synchronization Jump Width (SJW). The value of
the SJW will be added to phase segment 1 (see
Figure 5-2) or subtracted from phase segment 2 (see
Figure 5-3). The SJW represents the loop filtering of
the DPLL. The SJW is programmable between 1 TQ
and 4 TQ.
The phase error of an edge is given by the position of
the edge relative to Sync Seg, measured in TQ. The
phase error is defined in magnitude of TQ as follows:
• e = 0 if the edge lies within SYNCESEG
• e > 0 if the edge lies before the SAMPLE POINT
• e < 0 if the edge lies after the SAMPLE POINT of
the previous bit
If the magnitude of the phase error is less than or equal
to the programmed value of the synchronization jump
width, the effect of a resynchronization is the same as
that of a hard synchronization.
If the magnitude of the phase error is larger than the
synchronization jump width, and if the phase error is
positive, then phase segment 1 is lengthened by an
amount equal to the synchronization jump width.
If the magnitude of the phase error is larger than the
resynchronization jump width, and if the phase error is
negative, then phase segment 2 is shortened by an
amount equal to the synchronization jump width.
5.7.3
SYNCHRONIZATION RULES
• Only one synchronization within one bit time is
allowed
• An edge will be used for synchronization only if
the value detected at the previous sample point
(previously read bus value) differs from the bus
value immediately after the edge
• All other recessive to dominant edges fulfilling
rules 1 and 2 will be used for resynchronization
with the exception that a node transmitting a dominant bit will not perform a resynchronization as a
result of a recessive to dominant edge with a positive phase error
Clocking information will only be derived from recessive to dominant transitions. The property that only a
fixed maximum number of successive bits have the
same value ensures resynchronization to the bit stream
during a frame.
FIGURE 5-2:
LENGTHENING A BIT PERIOD
Input Signal
Sync
Prop
Segment
Phase
Segment 1
Phase
Segment 2
≤ SJW
Sample
Point
Nominal
Bit Length
Actual Bit
Length
TQ
© 2007 Microchip Technology Inc.
DS21291F-page 37
MCP2510
FIGURE 5-3:
SHORTENING A BIT PERIOD
Input Signal
Sync
Prop
Segment
Phase
Segment 1
Phase
Segment 2
≤ SJW
Sample
Point
Actual
Bit Length
5.9
Oscillator Tolerance
Nominal
Bit Length
TQ
5.8
Programming Time Segments
Some requirements for programming of the time segments:
• Prop Seg + Phase Seg 1 >= Phase Seg 2
• Prop Seg + Phase Seg 1 >= TDELAY
• Phase Seg 2 > Sync Jump Width
The bit timing requirements allow ceramic resonators
to be used in applications with transmission rates of up
to 125 kbit/sec, as a rule of thumb. For the full bus
speed range of the CAN protocol, a quartz oscillator is
required. A maximum node-to-node oscillator variation
of 1.7% is allowed.
For example, assuming that a 125 kHz CAN baud rate
with FOSC = 20 MHz is desired:
TOSC = 50 nsec, choose BRP<5:0> = 04h, then TQ =
500 nsec. To obtain 125 kHz, the bit time must be 16
TQ.
Typically, the sampling of the bit should take place at
about 60-70% of the bit time, depending on the system
parameters. Also, typically, the TDELAY is 1-2 TQ.
Sync Seg = 1 TQ; Prop Seg = 2 TQ; So setting Phase
Seg 1 = 7 TQ would place the sample at 10 TQ after the
transition. This would leave 6 TQ for Phase Seg 2.
Since Phase Seg 2 is 6, by the rules, SJW could be the
maximum of 4 TQ. However, normally a large SJW is
only necessary when the clock generation of the different nodes is inaccurate or unstable, such as using
ceramic resonators. So an SJW of 1 is typically
enough.
DS21291F-page 38
© 2007 Microchip Technology Inc.
MCP2510
5.10
Bit Timing Configuration
Registers
The configuration registers (CNF1, CNF2, CNF3) control the bit timing for the CAN bus interface. These registers can only be modified when the MCP2510 is in
configuration mode (see Section 9.0).
5.10.1
CNF1
The BRP<5:0> bits control the baud rate prescaler.
These bits set the length of TQ relative to the OSC1
input frequency, with the minimum length of TQ being 2
OSC1 clock cycles in length (when BRP<5:0> are set
to 000000). The SJW<1:0> bits select the synchronization jump width in terms of number of TQ’s.
5.10.2
CNF2
The PRSEG<2:0> bits set the length, in TQ’s, of the
propagation segment. The PHSEG1<2:0> bits set the
length, in TQ’s, of phase segment 1. The SAM bit controls how many times the RXCAN pin is sampled. Set-
REGISTER 5-1:
ting this bit to a ‘1’ causes the bus to be sampled three
times; twice at TQ/2 before the sample point, and once
at the normal sample point (which is at the end of phase
segment 1). The value of the bus is determined to be
the value read during at least two of the samples. If the
SAM bit is set to a ‘0’ then the RXCAN pin is sampled
only once at the sample point. The BTLMODE bit controls how the length of phase segment 2 is determined.
If this bit is set to a ‘1’ then the length of phase segment
2 is determined by the PHSEG2<2:0> bits of CNF3
(see Section 5.10.3). If the BTLMODE bit is set to a ‘0’
then the length of phase segment 2 is the greater of
phase segment 1 and the information processing time
(which is fixed at 2 TQ for the MCP2510).
5.10.3
CNF3
The PHSEG2<2:0> bits set the length, in TQ’s, of
Phase Segment 2, if the CNF2.BTLMODE bit is set to
a ‘1’. If the BTLMODE bit is set to a ‘0’ then the
PHSEG2<2:0> bits have no effect.
CNF1 - CONFIGURATION REGISTER1 (ADDRESS: 2Ah)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
SJW1
SJW0
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
bit 7
bit 0
bit 7-6
SJW<1:0>: Synchronization Jump Width Length
11 = Length = 4 x TQ
10 = Length = 3 x TQ
01 = Length = 2 x TQ
00 = Length = 1 x TQ
bit 5-0
BRP<5:0>: Baud Rate Prescaler
TQ = 2 x (BRP + 1) / FOSC
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
© 2007 Microchip Technology Inc.
x = Bit is unknown
DS21291F-page 39
MCP2510
REGISTER 5-2:
CNF2 - CONFIGURATION REGISTER2 (ADDRESS: 29h)
R/W-0
R/W-0
BTLMODE
SAM
R/W-0
R/W-0
R/W-0
PHSEG12 PHSEG11 PHSEG10
R/W-0
R/W-0
R/W-0
PRSEG2
PRSEG1
PRSEG0
bit 7
bit 0
bit 7
BTLMODE: Phase Segment 2 Bit Time Length
1 = Length of Phase Seg 2 determined by PHSEG22:PHSEG20 bits of CNF3
0 = Length of Phase Seg 2 is the greater of Phase Seg 1 and IPT (2TQ)
bit 6
SAM: Sample Point Configuration
1 = Bus line is sampled three times at the sample point
0 = Bus line is sampled once at the sample point
bit 5-3
PHSEG1<2:0>: Phase Segment 1 Length
(PHSEG1 + 1) x TQ
bit 2-0
PRSEG<2:0>: Propagation Segment Length
(PRSEG + 1) x TQ
Legend:
REGISTER 5-3:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
CNF3 - CONFIGURATION REGISTER 3 (ADDRESS: 28h)
U-0
R/W-0
U-0
U-0
U-0
R/W-0
R/W-0
R/W-0
—
WAKFIL
—
—
—
PHSEG22
PHSEG21
PHSEG20
bit 7
bit 0
bit 7
Unimplemented: Reads as '0'
bit 6
WAKFIL: Wake-up Filter
1 = Wake-up filter enabled
0 = Wake-up filter disabled
bit 5-3
Unimplemented: Reads as '0'
bit 2-0
PHSEG2<2:0>: Phase Segment 2 Length
(PHSEG2 + 1) x TQ
Note:
Minimum valid setting for Phase Segment 2 is 2TQ
Legend:
DS21291F-page 40
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
© 2007 Microchip Technology Inc.
MCP2510
6.0
ERROR DETECTION
The CAN protocol provides sophisticated error detection mechanisms. The following errors can be detected.
6.1
CRC Error
With the Cyclic Redundancy Check (CRC), the transmitter calculates special check bits for the bit sequence
from the start of a frame until the end of the data field.
This CRC sequence is transmitted in the CRC Field.
The receiving node also calculates the CRC sequence
using the same formula and performs a comparison to
the received sequence. If a mismatch is detected, a
CRC error has occurred and an error frame is generated. The message is repeated.
6.2
Acknowledge Error
In the acknowledge field of a message, the transmitter
checks if the acknowledge slot (which has sent out as
a recessive bit) contains a dominant bit. If not, no other
node has received the frame correctly. An acknowledge error has occurred; an error frame is generated;
and the message will have to be repeated.
6.3
Form Error
lf a node detects a dominant bit in one of the four segments including end of frame, interframe space,
acknowledge delimiter or CRC delimiter; then a form
error has occurred and an error frame is generated.
The message is repeated.
6.4
Bit Error
A Bit Error occurs if a transmitter sends a dominant bit
and detects a recessive bit or if it sends a recessive bit
and detects a dominant bit when monitoring the actual
bus level and comparing it to the just transmitted bit. In
the case where the transmitter sends a recessive bit
and a dominant bit is detected during the arbitration
field and the acknowledge slot, no bit error is generated
because normal arbitration is occurring.
6.5
Stuff Error
lf, between the start of frame and the CRC delimiter, six
consecutive bits with the same polarity are detected,
the bit stuffing rule has been violated. A stuff error
occurs and an error frame is generated. The message
is repeated.
© 2007 Microchip Technology Inc.
6.6
Error States
Detected errors are made public to all other nodes via
error frames. The transmission of the erroneous message is aborted and the frame is repeated as soon as
possible. Furthermore, each CAN node is in one of the
three error states “error-active”, “error-passive” or “busoff” according to the value of the internal error counters.
The error-active state is the usual state where the bus
node can transmit messages and active error frames
(made of dominant bits) without any restrictions. In the
error-passive state, messages and passive error
frames (made of recessive bits) may be transmitted.
The bus-off state makes it temporarily impossible for
the station to participate in the bus communication.
During this state, messages can neither be received
nor transmitted.
6.7
Error Modes and Error Counters
The MCP2510 contains two error counters: the
Receive Error Counter (REC) (see Register 6-2), and
the Transmit Error Counter (TEC) (see Register 6-1).
The values of both counters can be read by the MCU.
These counters are incremented or decremented in
accordance with the CAN bus specification.
The MCP2510 is error-active if both error counters are
below the error-passive limit of 128. It is error-passive
if at least one of the error counters equals or exceeds
128. It goes to bus-off if the transmit error counter
equals or exceeds the bus-off limit of 256. The device
remains in this state, until the bus-off recovery
sequence is received. The bus-off recovery sequence
consists of 128 occurrences of 11 consecutive recessive bits (see Figure 6-1). Note that the MCP2510, after
going bus-off, will recover back to error-active, without
any intervention by the MCU, if the bus remains idle for
128 X 11 bit times. If this is not desired, the error interrupt service routine should address this. The current
error mode of the MCP2510 can be read by the MCU
via the EFLG register (Register 6-3).
Additionally, there is an error state warning flag bit,
EFLG:EWARN, which is set if at least one of the error
counters equals or exceeds the error warning limit of
96. EWARN is reset if both error counters are less than
the error warning limit.
DS21291F-page 41
MCP2510
FIGURE 6-1:
ERROR MODES STATE DIAGRAM
RESET
Error-Active
REC > 127 or
TEC > 127
128 occurrences of
11 consecutive
“recessive” bits
REC < 127 or
TEC < 127
Error-Passive
TEC > 255
Bus-Off
REGISTER 6-1:
TEC - TRANSMITTER ERROR COUNTER (ADDRESS: 1Ch)
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
TEC7
TEC6
TEC5
TEC4
TEC3
TEC2
TEC1
TEC0
bit 7
bit 7-0
bit 0
TEC<7:0>: Transmit Error Count
Legend:
REGISTER 6-2:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
REC - RECEIVER ERROR COUNTER (ADDRESS: 1Dh)
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
REC7
REC6
REC5
REC4
REC3
REC2
REC1
REC0
bit 7
bit 7-0
bit 0
REC<7:0>: Receive Error Count
Legend:
DS21291F-page 42
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
© 2007 Microchip Technology Inc.
MCP2510
REGISTER 6-3:
EFLG - ERROR FLAG REGISTER (ADDRESS: 2Dh)
R/W-0
R/W-0
R-0
R-0
R-0
R-0
R-0
R-0
RX1OVR
RX0OVR
TXBO
TXEP
RXEP
TXWAR
RXWAR
EWARN
bit 7
bit 0
bit 7
RX1OVR: Receive Buffer 1 Overflow Flag
- Set when a valid message is received for RXB1 and CANINTF.RX1IF = 1
- Must be reset by MCU
bit 6
RX0OVR: Receive Buffer 0 Overflow Flag
- Set when a valid message is received for RXB0 and CANINTF.RX0IF = 1
- Must be reset by MCU
bit 5
TXBO: Bus-Off Error Flag
- Bit set when TEC reaches 255
- Reset after a successful bus recovery sequence
bit 4
TXEP: Transmit Error-Passive Flag
- Set when TEC is equal to or greater than 128
- Reset when TEC is less than 128
bit 3
RXEP: Receive Error-Passive Flag
- Set when REC is equal to or greater than 128
- Reset when REC is less than 128
bit 2
TXWAR: Transmit Error Warning Flag
- Set when TEC is equal to or greater than 96
- Reset when TEC is less than 96
bit 1
RXWAR: Receive Error Warning Flag
- Set when REC is equal to or greater than 96
- Reset when REC is less than 96
bit 0
EWARN: Error Warning Flag
- Set when TEC or REC is equal to or greater than 96 (TXWAR or RXWAR = 1)
- Reset when both REC and TEC are less than 96
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
© 2007 Microchip Technology Inc.
x = Bit is unknown
DS21291F-page 43
MCP2510
NOTES:
DS21291F-page 44
© 2007 Microchip Technology Inc.
MCP2510
7.0
INTERRUPTS
The device has eight sources of interrupts. The CANINTE register contains the individual interrupt enable
bits for each interrupt source. The CANINTF register
contains the corresponding interrupt flag bit for each
interrupt source. When an interrupt occurs the INT pin
is driven low by the MCP2510 and will remain low until
the Interrupt is cleared by the MCU. An Interrupt can
not be cleared if the respective condition still prevails.
It is recommended that the bit modify command be
used to reset flag bits in the CANINTF register rather
than normal write operations. This is to prevent unintentionally changing a flag that changes during the
write command, potentially causing an interrupt to be
missed.
It should be noted that the CANINTF flags are read/
write and an Interrupt can be generated by the MCU
setting any of these bits, provided the associated CANINTE bit is also set.
7.1
Interrupt Code Bits
The source of a pending interrupt is indicated in the
CANSTAT.ICOD (interrupt code) bits as indicated in
Register 9-2. In the event that multiple interrupts occur,
the INT will remain low until all interrupts have been
reset by the MCU, and the CANSTAT.ICOD bits will
reflect the code for the highest priority interrupt that is
currently pending. Interrupts are internally prioritized
such that the lower the ICOD value the higher the interrupt priority. Once the highest priority interrupt condition has been cleared, the code for the next highest
priority interrupt that is pending (if any) will be reflected
by the ICOD bits (see Table 7-1). Note that only those
interrupt sources that have their associated CANINTE
enable bit set will be reflected in the ICOD bits.
TABLE 7-1:
7.2
Transmit Interrupt
When the Transmit Interrupt is enabled (CANINTE.TXNIE = 1) an Interrupt will be generated on the
INT pin when the associated transmit buffer becomes
empty and is ready to be loaded with a new message.
The CANINTF.TXNIF bit will be set to indicate the
source of the interrupt. The interrupt is cleared by the
MCU resetting the TXNIF bit to a ‘0’.
7.3
Receive Interrupt
When the Receive Interrupt is enabled (CANINTE.RXNIE = 1) an interrupt will be generated on the
INT pin when a message has been successfully
received and loaded into the associated receive buffer.
This interrupt is activated immediately after receiving
the EOF field. The CANINTF.RXNIF bit will be set to
indicate the source of the interrupt. The interrupt is
cleared by the MCU resetting the RXNIF bit to a ‘0’.
7.4
Message Error Interrupt
When an error occurs during transmission or reception
of a message the message error flag (CANINTF.MERRF) will be set and, if the CANINTE.MERRE
bit is set, an interrupt will be generated on the INT pin.
This is intended to be used to facilitate baud rate determination when used in conjunction with listen-only
mode.
7.5
Bus Activity Wakeup Interrupt
When the MCP2510 is in sleep mode and the bus activity wakeup interrupt is enabled (CANINTE.WAKIE = 1),
an interrupt will be generated on the INT pin, and the
CANINTF.WAKIF bit will be set when activity is
detected on the CAN bus. This interrupt causes the
MCP2510 to exit sleep mode. The interrupt is reset by
the MCU clearing the WAKIF bit.
ICOD<2:0> DECODE
ICOD<2:0>
Boolean Expression
000
ERR•WAK•TX0•TX1•TX2•RX0•RX1
001
ERR
010
ERR•WAK
011
ERR•WAK•TX0
100
ERR•WAK•TX0•TX1
101
ERR•WAK•TX0•TX1•TX2
110
ERR•WAK•TX0•TX1•TX2•RX0
111
ERR•WAK•TX0•TX1•TX2•RX0•RX1
© 2007 Microchip Technology Inc.
DS21291F-page 45
MCP2510
7.6
Error Interrupt
When the error interrupt is enabled (CANINTE.ERRIE
= 1) an interrupt is generated on the INT pin if an overflow condition occurs or if the error state of transmitter
or receiver has changed. The Error Flag Register
(EFLG) will indicate one of the following conditions.
7.6.1
RECEIVER OVERFLOW
An overflow condition occurs when the MAB has
assembled a valid received message (the message
meets the criteria of the acceptance filters) and the
receive buffer associated with the filter is not available
for loading of a new message. The associated
EFLG.RXNOVR bit will be set to indicate the overflow
condition. This bit must be cleared by the MCU.
7.6.2
RECEIVER WARNING
The receive error counter has reached the MCU warning limit of 96.
7.6.3
TRANSMITTER WARNING
7.6.4
RECEIVER ERROR-PASSIVE
The receive error counter has exceeded the error- passive limit of 127 and the device has gone to error- passive state.
7.6.5
TRANSMITTER ERROR-PASSIVE
The transmit error counter has exceeded the errorpassive limit of 127 and the device has gone to errorpassive state.
7.6.6
BUS-OFF
The transmit error counter has exceeded 255 and the
device has gone to bus-off state.
7.7
Interrupt Acknowledge
Interrupts are directly associated with one or more status flags in the CANINTF register. Interrupts are pending as long as one of the flags is set. Once an interrupt
flag is set by the device, the flag can not be reset by the
MCU until the interrupt condition is removed.
The transmit error counter has reached the MCU warning limit of 96.
DS21291F-page 46
© 2007 Microchip Technology Inc.
MCP2510
REGISTER 7-1:
CANINTE - INTERRUPT ENABLE REGISTER (ADDRESS: 2Bh)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
MERRE
WAKIE
ERRIE
TX2IE
TX1IE
TX0IE
RX1IE
RX0IE
bit 7
bit 0
bit 7
MERRE: Message Error Interrupt Enable
1 = Interrupt on error during message reception or transmission
0 = Disabled
bit 6
WAKIE: Wakeup Interrupt Enable
1 = Interrupt on CAN bus activity
0 = Disabled
bit 5
ERRIE: Error Interrupt Enable (multiple sources in EFLG register)
1 = Interrupt on EFLG error condition change
0 = Disabled
bit 4
TX2IE: Transmit Buffer 2 Empty Interrupt Enable
1 = Interrupt on TXB2 becoming empty
0 = Disabled
bit 3
TX1IE: Transmit Buffer 1 Empty Interrupt Enable
1 = Interrupt on TXB1 becoming empty
0 = Disabled
bit 2
TX0IE: Transmit Buffer 0 Empty Interrupt Enable
1 = Interrupt on TXB0 becoming empty
0 = Disabled
bit 1
RX1IE: Receive Buffer 1 Full Interrupt Enable
1 = Interrupt when message received in RXB1
0 = Disabled
bit 0
RX0IE: Receive Buffer 0 Full Interrupt Enable
1 = Interrupt when message received in RXB0
0 = Disabled
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
© 2007 Microchip Technology Inc.
x = Bit is unknown
DS21291F-page 47
MCP2510
REGISTER 7-2:
CANINTF - INTERRUPT FLAG REGISTER (ADDRESS: 2Ch)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
MERRF
WAKIF
ERRIF
TX2IF
TX1IF
TX0IF
RX1IF
RX0IF
bit 7
bit 0
bit 7
MERRF: Message Error Interrupt Flag
1 = Interrupt pending (must be cleared by MCU to reset interrupt condition)
0 = No interrupt pending
bit 6
WAKIF: Wakeup Interrupt Flag
1 = Interrupt pending (must be cleared by MCU to reset interrupt condition)
0 = No interrupt pending
bit 5
ERRIF: Error Interrupt Flag (multiple sources in EFLG register)
1 = Interrupt pending (must be cleared by MCU to reset interrupt condition)
0 = No interrupt pending
bit 4
TX2IF: Transmit Buffer 2 Empty Interrupt Flag
1 = Interrupt pending (must be cleared by MCU to reset interrupt condition)
0 = No interrupt pending
bit 3
TX1IF: Transmit Buffer 1 Empty Interrupt Flag
1 = Interrupt pending (must be cleared by MCU to reset interrupt condition)
0 = No interrupt pending
bit 2
TX0IF: Transmit Buffer 0 Empty Interrupt Flag
1 = Interrupt pending (must be cleared by MCU to reset interrupt condition)
0 = No interrupt pending
bit 1
RX1IF: Receive Buffer 1 Full Interrupt Flag
1 = Interrupt pending (must be cleared by MCU to reset interrupt condition)
0 = No interrupt pending
bit 0
RX0IF: Receive Buffer 0 Full Interrupt Flag
1 = Interrupt pending (must be cleared by MCU to reset interrupt condition)
0 = No interrupt pending
Legend:
DS21291F-page 48
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
© 2007 Microchip Technology Inc.
MCP2510
8.0
OSCILLATOR
8.2
The MCP2510 is designed to be operated with a crystal
or ceramic resonator connected to the OSC1 and
OSC2 pins. The MCP2510 oscillator design requires
the use of a parallel cut crystal. Use of a series cut crystal may give a frequency out of the crystal manufacturers specifications. A typical oscillator circuit is shown in
Figure 8-1. The MCP2510 may also be driven by an
external clock source connected to the OSC1 pin as
shown in Figure 8-2 and Figure 8-3.
8.1
The clock out pin is provided to the system designer for
use as the main system clock or as a clock input for
other devices in the system. The CLKOUT has an internal prescaler which can divide FOSC by 1, 2, 4 and 8.
The CLKOUT function is enabled and the prescaler is
selected via the CANCNTRL register (see Register 91). The CLKOUT pin will be active upon system reset
and default to the slowest speed (divide by 8) so that it
can be used as the MCU clock. When sleep mode is
requested, the MCP2510 will drive sixteen additional
clock cycles on the CLKOUT pin before entering sleep
mode. The idle state of the CLKOUT pin in sleep mode
is low. When the CLKOUT function is disabled (CANCNTRL.CLKEN = ‘0’) the CLKOUT pin is in a high
impedance state.
Oscillator Startup Timer
The MCP2510 utilizes an oscillator startup timer (OST),
which holds the MCP2510 in reset, to insure that the
oscillator has stabilized before the internal state
machine begins to operate. The OST maintains reset
for the first 128 OSC1 clock cycles after power up,
RESET, or wake up from sleep mode occurs. It should
be noted that no SPI operations should be attempted
until after the OST has expired.
FIGURE 8-1:
CLKOUT Pin
The CLKOUT function is designed to guarantee that
thCLKOUT and tlCLKOUT timings are preserved when the
CLKOUT pin function is enabled, disabled, or the prescaler value is changed.
CRYSTAL/CERAMIC RESONATOR OPERATION
OSC1
C1
To internal logic
XTAL
C2
RF(2)
SLEEP
RS(1)
OSC2
Note 1: A series resistor, RS, may be required for AT strip cut crystals.
Note 2: The feedback resistor, RF , is typically in the range of 2 to 10 MΩ.
FIGURE 8-2:
EXTERNAL CLOCK SOURCE
Clock from
external system
OSC1
(1)
Open
OSC2
Note 1: A resistor to ground may be used to reduce system noise. This may increase system current.
Note 2: Duty cycle restrictions must be observed (see Table 12-2).
© 2007 Microchip Technology Inc.
DS21291F-page 49
MCP2510
FIGURE 8-3:
EXTERNAL SERIES RESONANT CRYSTAL OSCILLATOR CIRCUIT
330 kΩ
330 kΩ
74AS04
74AS04
To Other
Devices
74AS04
MCP2510
OSC1
0.1 mF
XTAL
Note 1: Duty cycle restrictions must be observed (see Table 12-2).
DS21291F-page 50
© 2007 Microchip Technology Inc.
MCP2510
9.0
MODES OF OPERATION
The MCP2510 has five modes of operation. These
modes are:
1.
2.
3.
4.
5.
Configuration Mode.
Normal Mode.
Sleep Mode.
Listen-Only Mode.
Loopback Mode.
The operational mode is selected via the CANCTRL.
REQOP bits (see Register 9-1). When changing
modes, the mode will not actually change until all pending message transmissions are complete. Because of
this, the user must verify that the device has actually
changed into the requested mode before further operations are executed. Verification of the current operating mode is done by reading the CANSTAT. OPMODE
bits (see Register 9-2).
9.1
Configuration Mode
The MCP2510 must be initialized before activation.
This is only possible if the device is in the configuration
mode. Configuration mode is automatically selected
after powerup or a reset, or can be entered from any
other mode by setting the CANTRL.REQOP bits to
‘100’. When configuration mode is entered all error
counters are cleared. Configuration mode is the only
mode where the following registers are modifiable:
•
•
•
•
CNF1, CNF2, CNF3
TXRTSCTRL
Acceptance Filter Registers
Acceptance Mask Registers
Only when the CANSTAT.OPMODE bits read as ‘100’
can the initialization be performed, allowing the configuration registers, acceptance mask registers, and the
acceptance filter registers to be written. After the configuration is complete, the device can be activated by
programming the CANCTRL.REQOP bits for normal
operation mode (or any other mode).
9.2
Sleep Mode
The MCP2510 has an internal sleep mode that is used
to minimize the current consumption of the device. The
SPI interface remains active even when the MCP2510
is in sleep mode, allowing access to all registers.
To enter sleep mode, the mode request bits are set in
the CANCTRL register. The CANSTAT.OPMODE bits
indicate whether the device successfully entered sleep
mode. These bits should be read after sending the
sleep command to the MCP2510. The MCP2510 is
active and has not yet entered sleep mode until these
bits indicate that sleep mode has been entered. When
in internal sleep mode, the wakeup interrupt is still
active (if enabled). This is done so the MCU can also
© 2007 Microchip Technology Inc.
be placed into a sleep mode and use the MCP2510 to
wake it up upon detecting activity on the bus.
Note:
Care must be exercised to not enter sleep
mode while the MCP2510 is transmitting a
message. If sleep mode is requested while
transmitting, the transmission will stop
without completing and errors will occur on
the bus. Also, the message will remain
pending and transmit upon wake up.
When in sleep mode, the MCP2510 stops its internal
oscillator. The MCP2510 will wake-up when bus activity
occurs or when the MCU sets, via the SPI interface, the
CANINTF.WAKIF bit to ‘generate’ a wake up attempt
(the CANINTF.WAKIF bit must also be set in order for
the wakeup interrupt to occur). The TXCAN pin will
remain in the recessive state while the MCP2510 is in
sleep mode. Note that Sleep Mode will be entered
immediately, even if a message is currently being
transmitted, so it is necessary to insure that all TXREQ
bits are clear before setting Sleep Mode.
9.2.1
WAKE-UP FUNCTIONS
The device will monitor the RXCAN pin for activity while
it is in sleep mode. If the CANINTE.WAKIE bit is set,
the device will wake up and generate an interrupt.
Since the internal oscillator is shut down when sleep
mode is entered, it will take some amount of time for the
oscillator to start up and the device to enable itself to
receive messages. The device will ignore the message
that caused the wake-up from sleep mode as well as
any messages that occur while the device is ‘waking
up.’ The device will wake up in listen-only mode. The
MCU must set normal mode before the MCP2510 will
be able to communicate on the bus.
The device can be programmed to apply a low-pass filter function to the RXCAN input line while in internal
sleep mode. This feature can be used to prevent the
device from waking up due to short glitches on the CAN
bus lines. The CNF3.WAKFIL bit enables or disables
the filter.
9.3
Listen Only Mode
Listen-only mode provides a means for the MCP2510
to receive all messages including messages with
errors. This mode can be used for bus monitor applications or for detecting the baud rate in ‘hot plugging’ situations. For auto-baud detection it is necessary that
there are at least two other nodes, which are communicating with each other. The baud rate can be detected
empirically by testing different values until valid messages are received. The listen-only mode is a silent
mode, meaning no messages will be transmitted while
in this state, including error flags or acknowledge signals. The filters and masks can be used to allow only
particular messages to be loaded into the receive registers, or the filter masks can be set to all zeros to allow
a message with any identifier to pass. The error
DS21291F-page 51
MCP2510
counters are reset and deactivated in this state. The listen-only mode is activated by setting the mode request
bits in the CANCTRL register.
9.4
Loopback Mode
This mode will allow internal transmission of messages
from the transmit buffers to the receive buffers without
actually transmitting messages on the CAN bus. This
mode can be used in system development and testing.
In this mode the ACK bit is ignored and the device will
allow incoming messages from itself just as if they were
coming from another node. The loopback mode is a
silent mode, meaning no messages will be transmitted
while in this state, including error flags or acknowledge
signals. The TXCAN pin will be in a reccessive state
while the device is in this mode. The filters and masks
can be used to allow only particular messages to be
loaded into the receive registers. The masks can be set
to all zeros to provide a mode that accepts all messages. The loopback mode is activated by setting the
mode request bits in the CANCTRL register.
REGISTER 9-1:
9.5
Normal Mode
This is the standard operating mode of the MCP2510.
In this mode the device actively monitors all bus messages and generates acknowledge bits, error frames,
etc. This is also the only mode in which the MCP2510
will transmit messages over the CAN bus.
CANCTRL - CAN CONTROL REGISTER (ADDRESS: XFh)
R/W-1
R/W-1
R/W-1
R/W-0
U-0
R/W-1
REQOP2
REQOP1
REQOP0
ABAT
—
CLKEN
R/W-1
bit 7
bit 0
bit 7-5
REQOP<2:0>: Request Operation Mode
000 = Set Normal Operation Mode
001 = Set Sleep Mode
010 = Set Loopback Mode
011 = Set Listen Only Mode
100 = Set Configuration Mode
All other values for REQOP bits are invalid and should not be used
bit 4
ABAT: Abort All Pending Transmissions
1 = Request abort of all pending transmit buffers
0 = Terminate request to abort all transmissions
bit 3
Unimplemented: Read as '0'
bit 2
CLKEN: CLKOUT Pin Enable
1 = CLKOUT pin enabled
0 = CLKOUT pin disabled (Pin is in high impedance state)
bit 1-0
CLKPRE <1:0>: CLKOUT Pin Prescaler
00 = FCLKOUT = System Clock/1
01 = FCLKOUT = System Clock/2
10 = FCLKOUT = System Clock/4
11 = FCLKOUT = System Clock/8
Note:
R/W-1
CLKPRE1 CLKPRE0
On power up, REQOP = b’111’
Legend:
DS21291F-page 52
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
© 2007 Microchip Technology Inc.
MCP2510
REGISTER 9-2:
CANSTAT - CAN STATUS REGISTER (ADDRESS: XEh)
R-1
R-0
R-0
OPMOD2 OPMOD1 OPMOD0
U-0
R-0
R-0
R-0
U-0
—
ICOD2
ICOD1
ICOD0
—
bit 7
bit 0
bit 7-5
OPMOD<2:0>: Operation Mode
000 = Device is in Normal Operation Mode
001 = Device is in Sleep Mode
010 = Device is in Loopback Mode
011 = Device is in Listen Only Mode
100 = Device is in Configuration Mode
bit 4
Unimplemented: Read as '0'
bit 3-1
ICOD<2:0>: Interrupt Flag Code
000 = No Interrupt
001 = Error Interrupt
010 = Wake Up Interrupt
011 = TXB0 Interrupt
100 = TXB1 Interrupt
101 = TXB2 Interrupt
110 = RXB0 Interrupt
111 = RXB1 Interrupt
bit 0
Unimplemented: Read as '0'
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
© 2007 Microchip Technology Inc.
x = Bit is unknown
DS21291F-page 53
MCP2510
NOTES:
DS21291F-page 54
© 2007 Microchip Technology Inc.
MCP2510
10.0
REGISTER MAP
writing of data. Some specific control and status registers allow individual bit modification using the SPI Bit
Modify command. The registers that allow this command are shown as shaded locations in Table 10-1. A
summary of the MCP2510 control registers is shown in
Table 10-2.
The register map for the MCP2510 is shown in
Table 10-1. Address locations for each register are
determined by using the column (higher order 4 bits)
and row (lower order 4 bits) values. The registers have
been arranged to optimize the sequential reading and
TABLE 10-1:
CAN CONTROLLER REGISTER MAP
Lower
Address
Bits
Higher Order Address Bits
x000 xxxx
x001 xxxx
x010 xxxx
0000
RXF0SIDH
RXF3SIDH
RXM0SIDH
TXB0CTRL
TXB1CTRL
TXB2CTRL
RXB0CTRL
RXB1CTRL
0001
RXF0SIDL
RXF3SIDL
RXM0SIDL
TXB0SIDH
TXB1SIDH
TXB2SIDH
RXB0SIDH
RXB1SIDH
0010
RXF0EID8
RXF3EID8
RXM0EID8
TXB0SIDL
TXB1SIDL
TXB2SIDL
RXB0SIDL
RXB1SIDL
0011
RXF0EID0
RXF3EID0
RXM0EID0
TXB0EID8
TXB1EID8
TXB2EID8
RXB0EID8
RXB1EID8
0100
RXF1SIDH
RXF4SIDH
RXM1SIDH
TXB0EID0
TXB1EID0
TXB2EID0
RXB0EID0
RXB1EID0
0101
RXF1SIDL
RXF4SIDL
RXM1SIDL
TXB0DLC
TXB1DLC
TXB2DLC
RXB0DLC
RXB1DLC
0110
RXF1EID8
RXF4EID8
RXM1EID8
TXB0D0
TXB1D0
TXB2D0
RXB0D0
RXB1D0
0111
RXF1EID0
RXF4EID0
RXM1EID0
TXB0D1
TXB1D1
TXB2D1
RXB0D1
RXB1D1
1000
RXF2SIDH
RXF5SIDH
CNF3
TXB0D2
TXB1D2
TXB2D2
RXB0D2
RXB1D2
1001
RXF2SIDL
RXF5SIDL
CNF2
TXB0D3
TXB1D3
TXB2D3
RXB0D3
RXB1D3
1010
RXF2EID8
RXF5EID8
CNF1
TXB0D4
TXB1D4
TXB2D4
RXB0D4
RXB1D4
1011
RXF2EID0
RXF5EID0
CANINTE
TXB0D5
TXB1D5
TXB2D5
RXB0D5
RXB1D5
1100
BFPCTRL
TEC
CANINTF
TXB0D6
TXB1D6
TXB2D6
RXB0D6
RXB1D6
1101
TXRTSCTRL
REC
EFLG
TXB0D7
TXB1D7
TXB2D7
RXB0D7
RXB1D7
1110
CANSTAT
CANSTAT
CANSTAT
CANSTAT
CANSTAT
CANSTAT
CANSTAT
CANSTAT
CANCTRL
CANCTRL
CANCTRL
CANCTRL
CANCTRL
CANCTRL
CANCTRL
CANCTRL
1111
Note:
x0011 xxxx x100 xxxx x101 xxxx x110 xxxx x111 xxxx
Shaded register locations indicate that these allow the user to manipulate individual bits using the ‘Bit Modify’ Command.
TABLE 10-2:
CONTROL REGISTER SUMMARY
Register
Name
Address
(Hex)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
POR/RST
Value
BFPCTRL
0C
—
—
B1BFS
B0BFS
B1BFE
B0BFE
B1BFM
B0BFM
--00 0000
TXRTSCTRL
0D
—
—
B2RTS
B1RTS
B0RTS
B2RTSM
B1RTSM
CANSTAT
xE
OPMOD2 OPMOD1 OPMOD0
—
ICOD2
ICOD1
CANCTRL
xF
REQOP2 REQOP1 REQOP0
ABAT
—
CLKEN
ICOD0
B0RTSM --xx x000
—
100- 000-
CLKPRE1 CLKPRE0 1110 -111
TEC
1C
Transmit Error Counter
0000 0000
REC
1D
Receive Error Counter
0000 0000
CNF3
28
—
CNF2
29
BTLMODE
SAM
CNF1
2A
SJW1
SJW0
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
0000 0000
CANINTE
2B
MERRE
WAKIE
ERRIE
TX2IE
TX1IE
TX0IE
RX1IE
RX0IE
0000 0000
CANINTF
2C
MERRF
WAKIF
ERRIF
TX2IF
TX1IF
TX0IF
RX1IF
RX0IF
0000 0000
EFLG
2D
RX1OVR
RX0OVR
TXBO
TXEP
RXEP
TXWAR
RXWAR
EWARN
0000 0000
TXB0CTRL
30
—
ABTF
MLOA
TXERR
TXREQ
—
TXP1
TXP0
-000 0-00
TXB1CTRL
40
—
ABTF
MLOA
TXERR
TXREQ
—
TXP1
TXP0
-000 0-00
WAKFIL
—
—
—
PHSEG22 PHSEG21 PHSEG20 -0-- -000
PHSEG12 PHSEG11 PHSEG10 PRSEG2
PRSEG1
PRSEG0 0000 0000
TXB2CTRL
50
—
ABTF
MLOA
TXERR
TXREQ
—
TXP1
TXP0
-000 0-00
RXB0CTRL
60
—
RXM1
RXM0
—
RXRTR
BUKT
BUKT
FILHIT0
-00- 0000
RXB1CTRL
70
—
RSM1
RXM0
—
RXRTR
FILHIT2
FILHIT1
FILHIT0
-00- 0000
© 2007 Microchip Technology Inc.
DS21291F-page 55
MCP2510
NOTES:
DS21291F-page 56
© 2007 Microchip Technology Inc.
MCP2510
11.0
SPI INTERFACE
11.5
11.1
Overview
The Read Status Instruction allows single instruction
access to some of the often used status bits for message reception and transmission.
The MCP2510 is designed to interface directly with the
Serial Peripheral Interface (SPI) port available on many
microcontrollers and supports Mode 0,0 and Mode 1,1.
Commands and data are sent to the device via the SI
pin, with data being clocked in on the rising edge of
SCK. Data is driven out by the MCP2510, on the SO
line, on the falling edge of SCK. The CS pin must be
held low while any operation is performed. Table 11-1
shows the instruction bytes for all operations. Refer to
Figure 11-8 and Figure 11-9 for detailed input and output timing diagrams for both Mode 0,0 and Mode 1,1
operation.
11.2
Read Instruction
The Read Instruction is started by lowering the CS pin.
The read instruction is then sent to the MCP2510 followed by the 8-bit address (A7 through A0). After the
read instruction and address are sent, the data stored
in the register at the selected address will be shifted out
on the SO pin. The internal address pointer is automatically incremented to the next address after each byte
of data is shifted out. Therefore it is possible to read the
next consecutive register address by continuing to provide clock pulses. Any number of consecutive register
locations can be read sequentially using this method.
The read operation is terminated by raising the CS pin
(Figure 11-2).
11.3
Write Instruction
The Write Instruction is started by lowering the CS pin.
The write instruction is then sent to the MCP2510 followed by the address and at least one byte of data. It is
possible to write to sequential registers by continuing to
clock in data bytes, as long as CS is held low. Data will
actually be written to the register on the rising edge of
the SCK line for the D0 bit. If the CS line is brought high
before eight bits are loaded, the write will be aborted for
that data byte, previous bytes in the command will have
been written. Refer to the timing diagram in
Figure 11-3 for more detailed illustration of the byte
write sequence.
11.4
Request To Send (RTS) Instruction
Read Status Instruction
The part is selected by lowering the CS pin and the
read status command byte, shown in Figure 11-6, is
sent to the MCP2510. After the command byte is sent,
the MCP2510 will return eight bits of data that contain
the status. If additional clocks are sent after the first
eight bits are transmitted, the MCP2510 will continue to
output the status bits as long as the CS pin is held low
and clocks are provided on SCK. Each status bit
returned in this command may also be read by using
the standard read command with the appropriate register address.
11.6
Bit Modify Instruction
The Bit Modify Instruction provides a means for setting
or clearing individual bits in specific status and control
registers. This command is not available for all registers. See Section 10.0 (register map) to determine
which registers allow the use of this command.
The part is selected by lowering the CS pin and the Bit
Modify command byte is then sent to the MCP2510.
After the command byte is sent, the address for the
register is sent followed by the mask byte and then the
data byte. The mask byte determines which bits in the
register will be allowed to change. A ‘1’ in the mask byte
will allow a bit in the register to change and a ‘0’ will not.
The data byte determines what value the modified bits
in the register will be changed to. A ‘1’ in the data byte
will set the bit and a ‘0’ will clear the bit, provided that
the mask for that bit is set to a ‘1’. (see Figure 11-1)
11.7
Reset Instruction
The Reset Instruction can be used to re-initialize the
internal registers of the MCP2510 and set configuration
mode. This command provides the same functionality,
via the SPI interface, as the RESET pin. The Reset
instruction is a single byte instruction which requires
selecting the device by pulling CS low, sending the
instruction byte, and then raising CS. It is highly recommended that the reset command be sent (or the
RESET pin be lowered) as part of the power-on initialization sequence. The MCP2510 will be held in reset
for 128 FOSC cycles.
The RTS command can be used to initiate message
transmission for one or more of the transmit buffers.
The part is selected by lowering the CS pin and the
RTS command byte is then sent to the MCP2510. As
shown in Figure 11-4, the last 3 bits of this command
indicate which transmit buffer(s) are enabled to send.
This command will set the TxBnCTRL.TXREQ bit for
the respective buffer(s). Any or all of the last three bits
can be set in a single command. If the RTS command
is sent with nnn = 000, the command will be ignored.
© 2007 Microchip Technology Inc.
DS21291F-page 57
MCP2510
FIGURE 11-1:
BIT MODIFY
Mask byte 0 0 1 1 0 1 0 1
Data byte X X 1 0 X 0 X 1
Previous
Register
Contents
0 1 0 1 0 0 0 1
Resulting
Register 0 1 1 0 0 0 0 1
Contents
TABLE 11-1:
SPI INSTRUCTION SET
Instruction Name
Instruction Format
Description
RESET
1100 0000
Resets internal registers to default state, set configuration mode
READ
0000 0011
Read data from register beginning at selected address
WRITE
0000 0010
Write data to register beginning at selected address
RTS
(Request To Send)
1000 0nnn
Sets TXBnCTRL.TXREQ bit for one or more transmit buffers
1000 0nnn
Request to send for TXB0
Request to send for TXB2
Request to send for TXB1
Read Status
1010 0000
Polling command that outputs status bits for transmit/receive functions
Bit Modify
0000 0101
Bit modify selected registers
FIGURE 11-2:
READ INSTRUCTION
CS
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23
SCK
instruction
0
SI
0
0
0
address byte
0
0
1
1
A7
6
5
4
3
2
1
don’t care
A0
data out
high impedance
SO
7
FIGURE 11-3:
6
5
4
3
2
1
0
BYTE WRITE INSTRUCTION
CS
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19
20 21 22 23
SCK
address byte
instruction
SI
0
0
0
0
0
0
1
0
A7
6
5
4
3
2
data byte
1
A0
7
6
5
4
3
2
1
0
high impedance
SO
DS21291F-page 58
© 2007 Microchip Technology Inc.
MCP2510
FIGURE 11-4:
REQUEST TO SEND INSTRUCTION
CS
0
1
2
3
4
5
6
7
SCK
instruction
1
SI
0
0
0
T2 T1 T0
high impedance
SO
FIGURE 11-5:
0
BIT MODIFY INSTRUCTION
CS
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
SCK
SI
data byte
mask byte
address byte
instruction
0 0 0 0 0 1 0 1 A7 6 5 4 3 2 1 A0 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
high impedance
SO
Note:
FIGURE 11-6:
Not all registers can be accessed with this command. See the register map in Section 10.0
for a list of the registers that apply.
READ STATUS INSTRUCTION
CS
0
1
2
3
4
5
6
7
0
0
0
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23
SCK
instruction
SI
SO
1
0
1
0
0
don’t care
repeat
data out
data out
high impedance
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
CANINTF.RX0IF
CANINTF.RX1IF
TXB0CNTRL.TXREQ
CANINTF.TX0IF
TXB1CNTRL.TXREQ
CANINTF.TX1IF
TXB2CNTRL.TXREQ
CANINTF.TX2IF
© 2007 Microchip Technology Inc.
DS21291F-page 59
MCP2510
FIGURE 11-7:
RESET INSTRUCTION
CS
0
1
2
3
4
5
6
7
0
0
0
SCK
instruction
SI
1
0
1
0
high impedance
SO
FIGURE 11-8:
0
SPI INPUT TIMING
3
CS
11
10
6
1
Mode 1,1
7
2
SCK Mode 0,0
4
5
SI
MSB in
LSB in
high impedance
SO
FIGURE 11-9:
SPI OUTPUT TIMING
CS
8
2
9
SCK
Mode 1,1
Mode 0,0
12
13
SO
SI
DS21291F-page 60
MSB out
14
LSB out
don’t care
© 2007 Microchip Technology Inc.
MCP2510
12.0
ELECTRICAL CHARACTERISTICS
12.1
Absolute Maximum Ratings†
VDD.............................................................................................................................................................................7.0V
All inputs and outputs w.r.t. VSS ..........................................................................................................-0.6V to VDD +1.0V
Storage temperature ...............................................................................................................................-65°C to +150°C
Ambient temp. with power applied ..........................................................................................................-65°C to +125°C
Soldering temperature of leads (10 seconds) ....................................................................................................... +300°C
ESD protection on all pins ......................................................................................................................................................≥ 4 kV
† Notice: Stresses above those listed under “Maximum Ratings” may cause permanent damage to the device. This
is a stress rating only and functional operation of the device at those or any other conditions above those indicated in
the operational listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability.
© 2007 Microchip Technology Inc.
DS21291F-page 61
MCP2510
TABLE 12-1:
DC CHARACTERISTICS
Industrial (I):
Extended (E):
DC Characteristics
Param.
No.
Sym
Characteristic
TAMB = -40°C to +85°C
TAMB = -40°C to +125°C
Min
Max
Units
VDD
Supply Voltage
3.0
5.5
V
VRET
Register Retention Voltage
2.4
—
V
High Level Input Voltage
VIH
RXCAN
Conditions
Note
2
VDD+1
V
SCK, CS, SI, TXnRTS Pins
.7 VDD
VDD+1
V
OSC1
.85 VDD
VDD
V
RESET
.85 VDD
VDD
V
Low Level Input Voltage
VIL
VDD = 3.0V to 5.5V
VDD = 4.5V to 5.5V
Note
RXCAN,TXnRTS Pins
-0.3
.15 VDD
V
SCK, CS, SI
-0.3
0.4
V
OSC1
VSS
.3 VDD
V
RESET
VSS
.15 VDD
V
TXCAN
—
0.6
V
IOL = -6.0 mA, VDD = 4.5V
RXnBF Pins
—
0.6
V
IOL = -8.5 mA, VDD = 4.5V
SO, CLKOUT
—
0.6
V
IOL = -2.1 mA, VDD = 4.5V
INT
—
0.6
V
IOL = -1.6 mA, VDD = 4.5V
Low Level Output Voltage
VOL
High Level Output Voltage
V
TXCAN, RXnBF Pins
VDD -0.7
—
V
IOH = 3.0 mA, VDD = 4.5V, I temp
SO, CLKOUT
VDD -0.5
—
V
IOH = 400 µA, VDD = 4.5V
INT
VDD -0.7
—
V
IOH = 1.0 mA, VDD = 4.5V
All I/O except OSC1 and
TXnRTS pins
-1
+1
µA
CS = RESET = VDD,
VIN = VSS to VDD
OSC1 Pin
-5
+5
µA
CINT
Internal Capacitance
(All Inputs And Outputs)
—
7
pF
TAMB = 25°C, fC = 1.0 MHz,
VDD = 5.0V (Note)
IDD
Operating Current
—
10
mA
VDD = 5.5V, FOSC = 25 MHz,
FCLK = 1 MHz, SO = Open
IDDS
Standby Current (Sleep Mode)
—
5
µA
CS, TXnRTS = VDD, Inputs tied to
VDD or VSS
VOH
Input Leakage Current
ILI
Note:
This parameter is periodically sampled and not 100% tested.
DS21291F-page 62
© 2007 Microchip Technology Inc.
MCP2510
TABLE 12-2:
OSCILLATOR TIMING CHARACTERISTICS
Oscillator Timing Characteristics
Param.
No.
Note:
Sym
Characteristic
Max
Units
Conditions
1
1
25
16
MHz
MHz
4.5V to 5.5V
3.0V to 4.5V
TOSC
Clock In Period
40
62.5
1000
1000
ns
ns
4.5V to 5.5V
3.0V to 4.5V
TDUTY
Duty Cycle (External Clock
Input)
0.45
0.55
—
TOSH / (TOSH + TOSL)
This parameter is periodically sampled and not 100% tested.
CAN INTERFACE AC CHARACTERISTICS
Sym
Characteristic
TWF
TDCLK
TABLE 12-4:
Industrial (I):
Extended (E):
TAMB = -40°C to +85°C
TAMB = -40°C to +125°C
Min
Max
Units
Wakeup Noise Filter
50
—
ns
CLOCKOUT Propagation
Delay
—
100
ns
VDD = 3.0V to 5.5V
VDD = 4.5V to 5.5V
Conditions
CLKOUT PIN AC/DC CHARACTERISTICS
CLKOUT Pin AC/DC Characteristics
Note:
Min
Clock In Frequency
CAN Interface AC Characteristics
Param.
No.
VDD = 3.0V to 5.5V
VDD = 4.5V to 5.5V
FOSC
TABLE 12-3:
Param.
No.
TAMB = -40°C to +85°C
TAMB = -40°C to +125°C
Industrial (I):
Extended (E):
Sym
Characteristic
Industrial (I):
Extended (E):
TAMB = -40°C to +85°C
TAMB = -40°C to +125°C
Min
Max
Units
VDD = 3.0V to 5.5V
VDD = 4.5V to 5.5V
Conditions
thCLKOUT
CLKOUT Pin High Time
15
—
ns
TOSC = 40 ns (Note)
tlCLKOUT
CLKOUT Pin Low Time
15
—
ns
TOSC = 40 ns (Note)
trCLKOUT
CLKOUT Pin Rise Time
—
5
ns
Measured from 0.3 VDD to 0.7 VDD
(Note)
tfCLKOUT
CLKOUT Pin Fall Time
—
5
ns
Measured from 0.7 VDD to 0.3 VDD
(Note)
tdCLKOUT
CLOCKOUT Propagation Delay
—
100
ns
CLKOUT prescaler set to divide by one.
© 2007 Microchip Technology Inc.
DS21291F-page 63
MCP2510
TABLE 12-5:
SPI INTERFACE AC CHARACTERISTICS
SPI Interface AC Characteristics
Param.
No.
Sym
Characteristic
Industrial (I):
Extended (E):
TAMB = -40°C to +85°C
TAMB = -40°C to +125°C
Min
Max
Units
—
—
—
5
4
2.5
MHz
MHz
MHz
VDD = 3.0V to 5.5V
VDD = 4.5V to 5.5V
Conditions
FCLK
Clock Frequency
1
TCSS
CS Setup Time
100
—
ns
2
TCSH
CS Hold Time
100
115
180
—
—
—
ns
ns
ns
VDD = 4.5V to 5.5V
VDD = 4.5V to 5.5V (E temp)
VDD = 3.0V to 4.5V
3
TCSD
CS Disable Time
100
100
280
—
—
—
ns
ns
ns
VDD = 4.5V to 5.5V
VDD = 4.5V to 5.5V (E temp)
VDD = 3.0V to 4.5V
4
TSU
Data Setup Time
20
20
30
—
—
—
ns
ns
ns
VDD = 4.5V to 5.5V
VDD = 4.5V to 5.5V (E temp)
VDD = 3.0V to 4.5V
5
THD
Data Hold Time
20
20
50
—
—
—
ns
ns
ns
VDD = 4.5V to 5.5V
VDD = 4.5V to 5.5V (E temp)
VDD = 3.0V to 4.5V
6
TR
CLK Rise Time
—
2
µs
Note
7
TF
CLK Fall Time
—
2
µs
Note
8
THI
Clock High Time
90
115
180
—
—
—
ns
ns
ns
VDD = 4.5V to 5.5V
VDD = 4.5V to 5.5V (E temp)
VDD = 3.0V to 4.5V
9
TLO
Clock Low Time
90
115
180
—
—
—
ns
ns
ns
VDD = 4.5V to 5.5V
VDD = 4.5V to 5.5V (E temp)
VDD = 3.0V to 4.5V
10
TCLD
Clock Delay Time
50
—
ns
11
TCLE
Clock Enable Time
50
—
ns
12
TV
Output Valid from Clock Low
—
—
—
90
115
180
ns
ns
ns
VDD = 4.5V to 5.5V
VDD = 4.5V to 5.5V (E temp)
VDD = 3.0V to 4.5V
13
THO
Output Hold Time
0
—
ns
Note
TDIS
Output Disable Time
—
200
ns
Note
14
Note:
VDD = 4.5V to 5.5V
VDD = 4.5V to 5.5V (E temp)
VDD = 3.0V to 4.5V
This parameter is not 100% tested.
DS21291F-page 64
© 2007 Microchip Technology Inc.
MCP2510
13.0
PACKAGING INFORMATION
13.1
Package Marking Information
18-Lead PDIP (300 mil)
Example:
XXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXX
YYWWNNN
18-Lead SOIC (300 mil)
XXXXXXXXXXXX
XXXXXXXXXXXX
XXXXXXXXXXXX
YYWWNNN
20-Lead TSSOP (4.4 mm)
MCP2510-I/P e3
XXXXXXXXXXXXXXXXX
0726NNN
Example:
MCP2510-I/SO e3
XXXXXXXXXXXX
XXXXXXXXXXXX
0737NNN
Example:
XXXXXXXX
MCP2510 e3
XXXXXNNN
I/STNNN
YYWW
0728
Legend: XX...X
Y
YY
WW
NNN
e3
*
Note:
Customer-specific information
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
Pb-free JEDEC designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator ( e3 )
can be found on the outer packaging for this package.
In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
© 2007 Microchip Technology Inc.
DS21291F-page 65
MCP2510
18-Lead Plastic Dual In-Line (P) – 300 mil Body [PDIP]
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
N
NOTE 1
E1
1
2
3
D
E
A2
A
L
c
A1
b1
b
e
eB
Units
Dimension Limits
Number of Pins
INCHES
MIN
N
Pitch
e
Top to Seating Plane
A
NOM
MAX
18
.100 BSC
–
–
.210
.195
Molded Package Thickness
A2
.115
.130
Base to Seating Plane
A1
.015
–
–
Shoulder to Shoulder Width
E
.300
.310
.325
Molded Package Width
E1
.240
.250
.280
Overall Length
D
.880
.900
.920
Tip to Seating Plane
L
.115
.130
.150
Lead Thickness
c
.008
.010
.014
Upper Lead Width
b1
.045
.060
.070
b
.014
.018
.022
eB
–
–
Lower Lead Width
Overall Row Spacing §
.430
Notes:
1. Pin 1 visual index feature may vary, but must be located within the hatched area.
2. § Significant Characteristic.
3. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010" per side.
4. Dimensioning and tolerancing per ASME Y14.5M.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
Microchip Technology Drawing C04-007B
DS21291F-page 66
© 2007 Microchip Technology Inc.
MCP2510
18-Lead Plastic Small Outline (SO) – Wide, 7.50 mm Body [SOIC]
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
D
N
E
E1
NOTE 1
1
2 3
b
e
α
h
h
c
φ
A2
A
A1
β
L
L1
Units
Dimension Limits
Number of Pins
MILLMETERS
MIN
N
NOM
MAX
18
Pitch
e
Overall Height
A
–
1.27 BSC
–
2.65
Molded Package Thickness
A2
2.05
–
–
Standoff §
A1
0.10
–
0.30
Overall Width
E
Molded Package Width
E1
7.50 BSC
Overall Length
D
11.55 BSC
10.30 BSC
Chamfer (optional)
h
0.25
–
0.75
Foot Length
L
0.40
–
1.27
Footprint
L1
Foot Angle
φ
0°
–
8°
Lead Thickness
c
0.20
–
0.33
Lead Width
b
0.31
–
0.51
Mold Draft Angle Top
α
5°
–
15°
Mold Draft Angle Bottom
β
5°
–
1.40 REF
15°
Notes:
1. Pin 1 visual index feature may vary, but must be located within the hatched area.
2. § Significant Characteristic.
3. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.15 mm per side.
4. Dimensioning and tolerancing per ASME Y14.5M.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
REF: Reference Dimension, usually without tolerance, for information purposes only.
Microchip Technology Drawing C04-051B
© 2007 Microchip Technology Inc.
DS21291F-page 67
MCP2510
20-Lead Plastic Thin Shrink Small Outline (ST) – 4.4 mm Body [TSSOP]
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
D
N
E
E1
NOTE 1
1 2
b
e
c
φ
A2
A
A1
L
L1
Units
Dimension Limits
Number of Pins
MILLIMETERS
MIN
N
NOM
MAX
20
Pitch
e
Overall Height
A
–
0.65 BSC
–
Molded Package Thickness
A2
0.80
1.00
1.05
Standoff
A1
0.05
–
0.15
1.20
Overall Width
E
Molded Package Width
E1
4.30
6.40 BSC
4.40
Molded Package Length
D
6.40
6.50
6.60
Foot Length
L
0.45
0.60
0.75
Footprint
L1
4.50
1.00 REF
Foot Angle
φ
0°
–
8°
Lead Thickness
c
0.09
–
0.20
Lead Width
b
0.19
–
0.30
Notes:
1. Pin 1 visual index feature may vary, but must be located within the hatched area.
2. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.15 mm per side.
3. Dimensioning and tolerancing per ASME Y14.5M.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
REF: Reference Dimension, usually without tolerance, for information purposes only.
Microchip Technology Drawing C04-088B
DS21291F-page 68
© 2007 Microchip Technology Inc.
MCP2510
APPENDIX A:
REVISION HISTORY
Revision F (January 2007)
This revision includes updates to the packaging
diagrams.
© 2007 Microchip Technology Inc.
DS21291F-page 69
NOTES:
DS21291F-page 70
© 2007 Microchip Technology Inc.
MCP2510
INDEX
A
Acknowledge Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
B
BFpctrl - RXnBF Pin Control and Status Register . . . . . . . 26
Bit Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
BIT Modify instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Bit Modify Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Bit Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Bit Timing Configuration Registers . . . . . . . . . . . . . . . . . . 39
Bit Timing Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Bus Activity Wakeup Interrupt . . . . . . . . . . . . . . . . . . . . . . 45
Bus Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Byte Write instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
L
Lenghtening a Bit Period . . . . . . . . . . . . . . . . . . . . . . . . . 37
Listen Only Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Loopback Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
M
Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Message Acceptance Filter . . . . . . . . . . . . . . . . . . . . . . .
Message Acceptance Filters and Masks . . . . . . . . . . . . .
Message Reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Message Reception Flowchart . . . . . . . . . . . . . . . . . . . . .
Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
61
30
29
21
23
51
N
Normal Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
C
O
CAN Buffers and Protocol Engine Block Diagram . . . . . . . . 5
CAN controller Register Map . . . . . . . . . . . . . . . . . . . . . . . 55
CAN Interface AC characteristics . . . . . . . . . . . . . . . . . . . 63
CAN Protocol Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
CAN Protocol Engine Block Diagram . . . . . . . . . . . . . . . . . 6
CANCTRL - CAN Control Register . . . . . . . . . . . . . . . . . . 52
CANINTE - Interrupt Enable Register . . . . . . . . . . . . . . . . 47
CANSTAT - CAN Status Register . . . . . . . . . . . . . . . . . . . 53
CNF1 - Configuration Register1 . . . . . . . . . . . . . . . . . . . . 39
CNF2 - Configuration Register2 . . . . . . . . . . . . . . . . . . . . 40
CNF3 - Configuration Register3 . . . . . . . . . . . . . . . . . . . . 40
Configuration Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
CRC Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Crystal/ceramic resonator operation . . . . . . . . . . . . . . . . . 49
Cyclic Redundancy Check . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Oscillator Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Overload Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
D
DC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Device Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
E
EFLG - Error Flag Register . . . . . . . . . . . . . . . . . . . . . . . . 43
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Errata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Error Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Error Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 13
Error Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Error Management Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Error Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Error Modes and Error Counters . . . . . . . . . . . . . . . . . . . . 41
Error States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Extended Data Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
External Clock (osc1) Timing characteristics . . . . . . . . . . . 63
External Clock Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
External Series Resonant Crystal Oscillator Circuit . . . . . . 50
F
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Filter/Mask Truth Table . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Form Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Frame Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
H
Hard Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
I
Information Processing Time . . . . . . . . . . . . . . . . . . . . . . . 36
Initiating Message Transmission . . . . . . . . . . . . . . . . . . . . 15
Interframe Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Interrupt Acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
© 2007 Microchip Technology Inc.
P
Package Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Packaging Information . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Phase Buffer Segments . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Programming Time Segments . . . . . . . . . . . . . . . . . . . . . 38
Propagation Segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Protocol Finite State Machine . . . . . . . . . . . . . . . . . . . . . . 6
R
Read Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Read instruction Diagram . . . . . . . . . . . . . . . . . . . . . . . . . 58
Read Status Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Read Status instruction . . . . . . . . . . . . . . . . . . . . . . . . . . 59
REC - Receiver Error Count . . . . . . . . . . . . . . . . . . . . . . . 42
Receive Buffers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Receive Buffers Diagram . . . . . . . . . . . . . . . . . . . . . . . . . 22
Receive Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Receive Message Buffering . . . . . . . . . . . . . . . . . . . . . . . 21
Receiver Error Passive . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Receiver Overrun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Receiver Warning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Remote Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Request To Send (RTS) Instruction . . . . . . . . . . . . . . 57, 59
Resynchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
RXB0BF and RXB1BF Pins . . . . . . . . . . . . . . . . . . . . . . . 21
RXB0CTRL - Receive Buffer 0 Control Register . . . . . . . 24
RXB1CTRL - Receive Buffer 1 Control Register . . . . . . . 25
RXBnDLC - Receive Buffer n Data Length Code . . . . . . . 28
RXBnDm - Receive Buffer n Data Field Byte m . . . . . . . . 28
RXBnEID0 - Receive Buffer n Extended Identifier Low . . 28
RXBnEID8 - Receive Buffer n Extended Identifier Mid . . 27
RXBnSIDH - Receive Buffer n Standard Identifier High . . 26
RXBnSIDL - Receive Buffer n Standard Identifier Low . . 27
RXFnEID0 - Acceptance Filter n Extended Identifier Low 32
RXFnEID8 - Acceptance Filter n Extended Identifier Mid 31
RXFnSIDH - Acceptance Filter n Standard Identifier High 30
RXFnSIDL - Acceptance Filter n Standard Identifier Low 31
RXMnEID0 - Acceptance Filter Mask n Extended Identifier
Low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
RXMnEID8 - Acceptance Filter Mask n Extended Identifier
Mid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
RXMnSIDH - Acceptance Filter Mask n Standard Identifier
High . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
DS21291F-page 71
MCP2510
RXMnSIDL - Acceptance Filter Mask n Standard Identifier
Low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
S
Sample Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Shortening a Bit Period . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Sleep Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
SPI Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
SPI Interface Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
SPI Port AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . 64
Standard Data Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Stuff Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Synchronization Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Synchronization Segment . . . . . . . . . . . . . . . . . . . . . . . . . 36
T
TEC - Transmitter Error Count . . . . . . . . . . . . . . . . . . . . . . 42
Time Quanta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Transmit Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Transmit Message Aborting . . . . . . . . . . . . . . . . . . . . . . . . 15
Transmit Message Buffering . . . . . . . . . . . . . . . . . . . . . . . 15
Transmit Message Buffers . . . . . . . . . . . . . . . . . . . . . . . . . 15
Transmit Message flowchart . . . . . . . . . . . . . . . . . . . . . . . 16
Transmit Message Priority . . . . . . . . . . . . . . . . . . . . . . . . . 15
Transmitter Error Passive . . . . . . . . . . . . . . . . . . . . . . . . . 46
Transmitter Warning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
TXBnCTRL Transmit buffer n Control Register . . . . . . . . . 17
TXBnDm - Transmit Buffer n Data Field Byte m . . . . . . . . 20
TXBnEID0 - Transmit Buffer n Extended Identifier Low . . 20
TXBnEID8 - Transmit Buffer n Extended Identifier Mid . . . 19
TXBnEIDH - Transmit Buffer n Extended Identifier High . . 19
TXBnSIDH - Transmit Buffer n Standard Identifier High . . 18
TXBnSIDL - Transmit Buffer n Standard Identifier Low . . . 19
TXnRTS Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
TXRTSCTRL - TXBNRTS Pin Control and Status Register .
18
Typical System Implementation . . . . . . . . . . . . . . . . . . . . . . 4
W
WAKE-up functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Write Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
WWW, On-Line Support . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
DS21291F-page 72
© 2007 Microchip Technology Inc.
MCP2510
THE MICROCHIP WEB SITE
CUSTOMER SUPPORT
Microchip provides online support via our WWW site at
www.microchip.com. This web site is used as a means
to make files and information easily available to
customers. Accessible by using your favorite Internet
browser, the web site contains the following
information:
Users of Microchip products can receive assistance
through several channels:
• Product Support – Data sheets and errata,
application notes and sample programs, design
resources, user’s guides and hardware support
documents, latest software releases and archived
software
• General Technical Support – Frequently Asked
Questions (FAQ), technical support requests,
online discussion groups, Microchip consultant
program member listing
• Business of Microchip – Product selector and
ordering guides, latest Microchip press releases,
listing of seminars and events, listings of
Microchip sales offices, distributors and factory
representatives
•
•
•
•
•
Distributor or Representative
Local Sales Office
Field Application Engineer (FAE)
Technical Support
Development Systems Information Line
Customers
should
contact
their
distributor,
representative or field application engineer (FAE) for
support. Local sales offices are also available to help
customers. A listing of sales offices and locations is
included in the back of this document.
Technical support is available through the web site
at: http://support.microchip.com
CUSTOMER CHANGE NOTIFICATION
SERVICE
Microchip’s customer notification service helps keep
customers current on Microchip products. Subscribers
will receive e-mail notification whenever there are
changes, updates, revisions or errata related to a
specified product family or development tool of interest.
To register, access the Microchip web site at
www.microchip.com, click on Customer Change
Notification and follow the registration instructions.
© 2007 Microchip Technology Inc.
Advance Information
DS21291F-page 73
MCP2510
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation
can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150.
Please list the following information, and use this outline to provide us with your comments about this document.
To:
Technical Publications Manager
RE:
Reader Response
Total Pages Sent ________
From: Name
Company
Address
City / State / ZIP / Country
Telephone: (_______) _________ - _________
FAX: (______) _________ - _________
Application (optional):
Would you like a reply?
Device: MCP2510
Y
N
Literature Number: DS21291F
Questions:
1. What are the best features of this document?
2. How does this document meet your hardware and software development needs?
3. Do you find the organization of this document easy to follow? If not, why?
4. What additions to the document do you think would enhance the structure and subject?
5. What deletions from the document could be made without affecting the overall usefulness?
6. Is there any incorrect or misleading information (what and where)?
7. How would you improve this document?
DS21291F-page 74
Advance Information
© 2007 Microchip Technology Inc.
MCP2510
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
X
PART NO.
Device
/XX
Temperature
Range
Package
Examples:
a)
MCP2510-E/P:
Extended
temperature,
Industrial
temperature,
PDIP package.
b)
MCP2510-I/P:
PDIP package.
Device:
MCP2510:
MCP2510T:
CAN Controller w/SPI Interface
CAN Controller w/SPI Interface
(Tape and Reel)
c)
MCP2510-E/SO:
SOIC package.
Extended
temperature,
d)
MCP2510-I/SO:
Industrial
temperature,
SOIC package.
Temperature Range:
E
= -40°C to +85°C
= -40°C to +125°C
Package:
P
= Plastic DIP (300 mil Body), 18-Lead
SO = Plastic SOIC (300 mil Body), 18-Lead
ST = TSSOP, (4.4 mm Body), 20-Lead
© 2007 Microchip Technology Inc.
e)
MCP2510-I/SO:
f)
MCP2510I/ST:
TSSOP package.
g)
MCP2510T-I/ST:
Tape and Reel, Industrial
temperature, SOIC package.
Industrial
temperature,
Tape and Reel, Industrial
temperature, TSSOP package.
DS21291F-page75
MCP2510
NOTES:
DS21291F-page 76
© 2007 Microchip Technology Inc.
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
•
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR
WARRANTIES OF ANY KIND WHETHER EXPRESS OR
IMPLIED, WRITTEN OR ORAL, STATUTORY OR
OTHERWISE, RELATED TO THE INFORMATION,
INCLUDING BUT NOT LIMITED TO ITS CONDITION,
QUALITY, PERFORMANCE, MERCHANTABILITY OR
FITNESS FOR PURPOSE. Microchip disclaims all liability
arising from this information and its use. Use of Microchip
devices in life support and/or safety applications is entirely at
the buyer’s risk, and the buyer agrees to defend, indemnify and
hold harmless Microchip from any and all damages, claims,
suits, or expenses resulting from such use. No licenses are
conveyed, implicitly or otherwise, under any Microchip
intellectual property rights.
Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, KEELOQ, microID, MPLAB, PIC, PICmicro, PICSTART,
PRO MATE, PowerSmart, rfPIC, and SmartShunt are
registered trademarks of Microchip Technology Incorporated
in the U.S.A. and other countries.
AmpLab, FilterLab, Migratable Memory, MXDEV, MXLAB,
SEEVAL, SmartSensor and The Embedded Control Solutions
Company are registered trademarks of Microchip Technology
Incorporated in the U.S.A.
Analog-for-the-Digital Age, Application Maestro, CodeGuard,
dsPICDEM, dsPICDEM.net, dsPICworks, ECAN,
ECONOMONITOR, FanSense, FlexROM, fuzzyLAB,
In-Circuit Serial Programming, ICSP, ICEPIC, Linear Active
Thermistor, Mindi, MiWi, MPASM, MPLIB, MPLINK, PICkit,
PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal,
PowerInfo, PowerMate, PowerTool, REAL ICE, rfLAB,
rfPICDEM, Select Mode, Smart Serial, SmartTel, Total
Endurance, UNI/O, WiperLock and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2007, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received ISO/TS-16949:2002 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona, Gresham, Oregon and Mountain View, California. The
Company’s quality system processes and procedures are for its PIC®
MCUs and dsPIC DSCs, KEELOQ® code hopping devices, Serial
EEPROMs, microperipherals, nonvolatile memory and analog
products. In addition, Microchip’s quality system for the design and
manufacture of development systems is ISO 9001:2000 certified.
© 2007 Microchip Technology Inc.
DS21291F-page 77
WORLDWIDE SALES AND SERVICE
AMERICAS
ASIA/PACIFIC
ASIA/PACIFIC
EUROPE
Corporate Office
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7200
Fax: 480-792-7277
Technical Support:
http://support.microchip.com
Web Address:
www.microchip.com
Asia Pacific Office
Suites 3707-14, 37th Floor
Tower 6, The Gateway
Habour City, Kowloon
Hong Kong
Tel: 852-2401-1200
Fax: 852-2401-3431
India - Bangalore
Tel: 91-80-4182-8400
Fax: 91-80-4182-8422
India - New Delhi
Tel: 91-11-4160-8631
Fax: 91-11-4160-8632
Austria - Wels
Tel: 43-7242-2244-39
Fax: 43-7242-2244-393
Denmark - Copenhagen
Tel: 45-4450-2828
Fax: 45-4485-2829
India - Pune
Tel: 91-20-2566-1512
Fax: 91-20-2566-1513
France - Paris
Tel: 33-1-69-53-63-20
Fax: 33-1-69-30-90-79
Japan - Yokohama
Tel: 81-45-471- 6166
Fax: 81-45-471-6122
Germany - Munich
Tel: 49-89-627-144-0
Fax: 49-89-627-144-44
Atlanta
Duluth, GA
Tel: 678-957-9614
Fax: 678-957-1455
Boston
Westborough, MA
Tel: 774-760-0087
Fax: 774-760-0088
Chicago
Itasca, IL
Tel: 630-285-0071
Fax: 630-285-0075
Dallas
Addison, TX
Tel: 972-818-7423
Fax: 972-818-2924
Detroit
Farmington Hills, MI
Tel: 248-538-2250
Fax: 248-538-2260
Kokomo
Kokomo, IN
Tel: 765-864-8360
Fax: 765-864-8387
Los Angeles
Mission Viejo, CA
Tel: 949-462-9523
Fax: 949-462-9608
Santa Clara
Santa Clara, CA
Tel: 408-961-6444
Fax: 408-961-6445
Toronto
Mississauga, Ontario,
Canada
Tel: 905-673-0699
Fax: 905-673-6509
Australia - Sydney
Tel: 61-2-9868-6733
Fax: 61-2-9868-6755
China - Beijing
Tel: 86-10-8528-2100
Fax: 86-10-8528-2104
China - Chengdu
Tel: 86-28-8665-5511
Fax: 86-28-8665-7889
Korea - Gumi
Tel: 82-54-473-4301
Fax: 82-54-473-4302
China - Fuzhou
Tel: 86-591-8750-3506
Fax: 86-591-8750-3521
Korea - Seoul
Tel: 82-2-554-7200
Fax: 82-2-558-5932 or
82-2-558-5934
China - Hong Kong SAR
Tel: 852-2401-1200
Fax: 852-2401-3431
Malaysia - Penang
Tel: 60-4-646-8870
Fax: 60-4-646-5086
China - Qingdao
Tel: 86-532-8502-7355
Fax: 86-532-8502-7205
Philippines - Manila
Tel: 63-2-634-9065
Fax: 63-2-634-9069
China - Shanghai
Tel: 86-21-5407-5533
Fax: 86-21-5407-5066
Singapore
Tel: 65-6334-8870
Fax: 65-6334-8850
China - Shenyang
Tel: 86-24-2334-2829
Fax: 86-24-2334-2393
Taiwan - Hsin Chu
Tel: 886-3-572-9526
Fax: 886-3-572-6459
China - Shenzhen
Tel: 86-755-8203-2660
Fax: 86-755-8203-1760
Taiwan - Kaohsiung
Tel: 886-7-536-4818
Fax: 886-7-536-4803
China - Shunde
Tel: 86-757-2839-5507
Fax: 86-757-2839-5571
Taiwan - Taipei
Tel: 886-2-2500-6610
Fax: 886-2-2508-0102
China - Wuhan
Tel: 86-27-5980-5300
Fax: 86-27-5980-5118
Thailand - Bangkok
Tel: 66-2-694-1351
Fax: 66-2-694-1350
Italy - Milan
Tel: 39-0331-742611
Fax: 39-0331-466781
Netherlands - Drunen
Tel: 31-416-690399
Fax: 31-416-690340
Spain - Madrid
Tel: 34-91-708-08-90
Fax: 34-91-708-08-91
UK - Wokingham
Tel: 44-118-921-5869
Fax: 44-118-921-5820
China - Xian
Tel: 86-29-8833-7250
Fax: 86-29-8833-7256
12/08/06
DS21291F-page 78
© 2007 Microchip Technology Inc.
MCP2510
Stand-Alone CAN Controller with SPI™ Interface 1
1.0
Device Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.0
Can Message Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.0
Message Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.0
Message Reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.0
Bit Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
6.0
Error Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
7.0
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
8.0
Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.0
Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
10.0
Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
11.0
SPI Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
12.0
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
13.0
Packaging Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
On-Line Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Reader Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Product Identification System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Worldwide Sales and Service ............................................................................................................................................................. 76
© 2007 Microchip Technology Inc.
DS21291F-page 79
MCP2510
DS21291F-page 80
© 2007 Microchip Technology Inc.