DSPIC30F6012 MICROCHIP [Microchip Technology], DSPIC30F6012 Datasheet - Page 113

• Manufacturer Part Number: DSPIC30F6012
• Description: High-Performance, 16-Bit Digital Signal Controllers
• Manufacturer: MICROCHIP [Microchip Technology]

17.0
17.1
The Controller Area Network (CAN) module is a serial
interface, useful for communicating with other CAN
modules or microcontroller devices. This interface/
protocol was designed to allow communications within
noisy environments.
The CAN module is a communication controller imple-
menting the CAN 2.0 A/B protocol, as defined in the
BOSCH specification. The module will support
CAN 1.2, CAN 2.0A, CAN 2.0B Passive, and CAN 2.0B
Active versions of the protocol. The module implemen-
tation is a full CAN system. The CAN specification is
not covered within this data sheet. The reader may
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
• Support for remote frames
• Double-buffered receiver with two prioritized
• 6 full (standard/extended identifier) acceptance
• 2 full acceptance filter masks, one each
• Three transmit buffers with application specified
• Programmable wake-up functionality with
• Programmable Loopback mode supports self-test
• Signaling via interrupt capabilities for all CAN
• Programmable clock source
• Programmable link to Input Capture module (IC2,
• Low-power Sleep and Idle mode
© 2006 Microchip Technology Inc.
Note: This data sheet summarizes features of this group
of dsPIC30F devices and is not intended to be a complete
reference source. For more information on the CPU,
peripherals, register descriptions and general device
functionality, refer to the “dsPIC30F Family Reference
Manual” (DS70046).
CAN 2.0A and CAN 2.0B
received message storage buffers (each buffer
may contain up to 8 bytes of data)
filters, 2 associated with the high priority receive
buffer and 4 associated with the low priority
receive buffer
associated with the high and low priority receive
buffers
prioritization and abort capability (each buffer may
contain up to 8 bytes of data)
integrated low-pass filter
operation
receiver and transmitter error states
for both CAN1 and CAN2) for time-stamping and
network synchronization
CAN MODULE
Overview
dsPIC30F6011/6012/6013/6014
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.
17.2
The CAN 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:
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 desti-
nation node sends a remote frame with an identi-
fier that matches the identifier of the required data
frame. The appropriate data source node will then
send 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 2
fields: an error flag field and an error delimiter
field.
An overload frame can be generated by a node as
a result of 2 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 may 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
DS70117F-page 111