AN2320 Freescale Semiconductor / Motorola, AN2320 Datasheet - Page 2

• Manufacturer Part Number: AN2320
• Description: Interfacing the MCF5272 to a Standalone CAN Controller
• Manufacturer: Freescale Semiconductor / Motorola

MCF5272 Microprocessor
The reference design is based on the M5272C3 development board using a daughter card to provide the
standalone CAN controller circuitry. This application note details the design process, starting with an
overview of the MCF5272 processor and the 82C900 CAN controller, and the reasons for choosing them.
It is followed by a more detailed look at both the hardware design and software development. Full
schematics and basic example application software can be downloaded from the M5272C3 CAN webpage
on Motorola’s ColdFire website. Motorola websites referred to in this document can be accessed from
www.motorola.com/semiconductors.
1.0 Design Overview
The object of this section is to outline the principles of the MCF5272 CAN reference design, to give an
overview of the MCF5272 microprocessor and the 82C900 CAN controller, and to explain the reasons for
choosing them for this design. For additional and more detailed information on the MCF5272 and the
82C900 themselves, please refer to the MCF5272 webpage, and the 82C900 user’s manual,
http://www.infineon.com/cgi/ecrm.dll/ecrm/scripts/public_download.jsp?oid=16123&parent_oid=16899.
Figure 1 shows the basics of the reference design. The MCF5272 microprocessor is interfaced to the
Infineon 82C900 CAN controller using a Queued Serial Peripheral Interface (QSPI). The CAN controller
implements the CAN protocol while an external CAN transceiver, the Philips PCA82C250, provides
physical connection to the CAN bus. Two transceivers are shown here, as the Infineon CAN controller is a
twin CAN device with dual CAN nodes allowing connection to two independent CAN buses. There is no
need for a second transceiver if only one node is required.
1.1
The MCF5272 is a 32-bit embedded processor based on a V2 ColdFire core. This is the most
application-specific ColdFire processor to date, targeted at the low-end communications market. On-chip
peripherals include a Fast Ethernet Controller, a USB 1.1 slave device, a Physical Layer Interface Channel
2
MCF5272 Microprocessor
MCF5272
ColdFire
QSPI_Clk
QSPI_CSn
QSPI_Din
QSPI_Dout
Interfacing the MCF5272 to a Standalone CAN Controller
Figure 1. MCF5272 CAN Reference Design Overview
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
SCLK
SLS
MRST
MTSR
Transceiver
PCA82C250
CAN Bus A
CAN Controller
Philips
CAN
Tx
Infineon
82C900
Rx
Tx
CAN Bus B
Transceiver
PCA82C250
Rx
Philips
CAN
MOTOROLA