Datasheet

© 2009-2012 Microchip Technology Inc. Preliminary DS70616F-page 357
dsPIC33EPXXX(GP/MC/MU)806/810/814 and PIC24EPXXX(GP/GU)810/814
21.0 ENHANCED CAN (ECAN™)
MODULE
21.1 Overview
The Enhanced Controller Area Network (ECAN)
module is a serial interface, useful for communicat-
ing with other CAN modules or microcontroller
devices. This interface/protocol was designed to
allow communications within noisy environments.
The dsPIC33EPXXX(GP/MC/MU)806/810/814 and
PIC24EPXXX(GP/GU)810/814 devices contain 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 implemen-
tation 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 ECAN module features are as follows:
• Implementation of the CAN protocol, CAN 1.2,
CAN 2.0A and CAN 2.0B
• Standard and extended data frames
• 0-8 bytes data length
• Programmable bit rate up to 1 Mbit/sec
• Automatic response to remote transmission
requests
• Up to eight transmit buffers with application speci-
fied prioritization and abort capability (each buffer
can contain up to 8 bytes of data)
• Up to 32 receive buffers (each buffer can contain
up to 8 bytes of data)
• Up to 16 full (standard/extended identifier)
acceptance filters
• Three full acceptance filter masks
• DeviceNet™ addressing support
• Programmable wake-up functionality with
integrated low-pass filter
• Programmable Loopback mode supports self-test
operation
• Signaling via interrupt capabilities for all CAN
receiver and transmitter error states
• Programmable clock source
• Programmable link to Input Capture module (IC2
for the ECAN1 and ECAN2 modules) for time-
stamping and network synchronization
• 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.
Note 1: This data sheet summarizes the features
of the dsPIC33EPXXX(GP/MC/MU)806/
810/814 and PIC24EPXXX(GP/GU)810/
814 families of devices. It is not intended
to be a comprehensive reference source.
To complement the information in this
data sheet, refer to Section 21.
“Enhanced Controller Area Network
(ECAN™)” (DS70353) of the “dsPIC33E/
PIC24E Family Reference Manual”,
which is available from the Microchip web
site (www.microchip.com).
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
Section 4.0 “Memory Organization” in
this data sheet for device-specific register
and bit information.