dspic33fj128mc204 Microchip Technology Inc., dspic33fj128mc204 Datasheet - Page 245

• Manufacturer Part Number: dspic33fj128mc204
• Description: High-performance, 16-bit Digital Signal Controllers
• Manufacturer: Microchip Technology Inc.

21.0
21.1
The Enhanced Controller Area Network (ECAN)
module is a serial interface, useful for communicating
with other CAN modules or microcontroller devices.
This
communications within noisy environments. The
dsPIC33FJ32MC302/304, dsPIC33FJ64MCX02/X04,
and dsPIC33FJ128MCX02/X04 devices contain up to
two ECAN modules.
The ECAN module is a communication controller
implementing the CAN 2.0 A/B protocol, as defined in
the BOSCH CAN specification. The module supports
CAN 1.2, CAN 2.0A, CAN 2.0B Passive and CAN 2.0B
Active versions of the protocol. The module implementa-
tion is a full CAN system. The CAN specification is not
covered within this data sheet. The reader can refer to
the BOSCH CAN specification for further details.
The module features are as follows:
• Implementation of the CAN protocol, CAN 1.2,
• Standard and extended data frames
• 0-8 bytes data length
• Programmable bit rate up to 1 Mbit/sec
• Automatic response to remote transmission
• Up to eight transmit buffers with application
• Up to 32 receive buffers (each buffer can contain
• Up to 16 full (standard/extended identifier)
• Three full acceptance filter masks
• DeviceNet™ addressing support
• Programmable wake-up functionality with
• Programmable Loopback mode supports self-test
• Signaling via interrupt capabilities for all CAN
• Programmable clock source
© 2009 Microchip Technology Inc.
Note:
CAN 2.0A and CAN 2.0B
requests
specified prioritization and abort capability (each
buffer can contain up to 8 bytes of data)
up to 8 bytes of data)
acceptance filters
integrated low-pass filter
operation
receiver and transmitter error states
interface/protocol
ENHANCED CAN (ECAN™)
MODULE
Overview
This data sheet summarizes the features
of
dsPIC33FJ64MCX02/X04,
dsPIC33FJ128MCX02/X04
devices. It is not intended to be a
comprehensive reference source. To com-
plement the information in this data sheet,
refer to the “dsPIC33F Family Reference
Manual”, Section 21. “Enhanced Con-
troller
(DS70185), which is available from the
Microchip website (www.microchip.com).
the
Area
was
dsPIC33FJ32MC302/304,
Network
designed
families
(ECAN™)”
to
allow
and
Preliminary
of
• Programmable link to input capture module (IC2
• Low-power Sleep and Idle mode
The CAN bus module consists of a protocol engine and
message buffering/control. The CAN protocol engine
handles all functions for receiving and transmitting
messages on the CAN bus. Messages are transmitted
by first loading the appropriate data registers. Status
and errors can be checked by reading the appropriate
registers. Any message detected on the CAN bus is
checked for errors and then matched against filters to
see if it should be received and stored in one of the
receive registers.
21.2
The ECAN module transmits various types of frames
which include data messages, or remote transmission
requests initiated by the user, as other frames that are
automatically generated for control purposes. The
following frame types are supported:
• Standard Data Frame:
• Extended Data Frame:
• Remote Frame:
• Error Frame:
• Overload Frame:
• Interframe Space:
for CAN1) for time-stamping and network
synchronization
A standard data frame is generated by a node
when the node wishes to transmit data. It includes
an 11-bit Standard Identifier (SID), but not an
18-bit Extended Identifier (EID).
An extended data frame is similar to a standard
data frame, but includes an extended identifier as
well.
It is possible for a destination node to request the
data from the source. For this purpose, the
destination node sends a remote frame with an
identifier that matches the identifier of the required
data frame. The appropriate data source node
sends a data frame as a response to this remote
request.
An error frame is generated by any node that
detects a bus error. An error frame consists of two
fields: an error flag field and an error delimiter
field.
An overload frame can be generated by a node as
a result of two conditions. First, the node detects
a dominant bit during interframe space which is an
illegal condition. Second, due to internal condi-
tions, the node is not yet able to start reception of
the next message. A node can generate a maxi-
mum of 2 sequential overload frames to delay the
start of the next message.
Interframe space separates a proceeding frame
(of whatever type) from a following data or remote
frame.
Frame Types
DS70291C-page 243