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ADSP-BF537 EZ-KIT Lite CAN Receive Example

Analog Devices, Inc.
DSP Division
Three Technology Way
Norwood, MA 02062

Date Created:	12/10/04

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This directory contains an example ADSP-BF537 project that shows how Port Pins, Interrupts, and
the CAN interface can be configured in C. It also demonstrates how to access the LEDs on the EZ-KIT
Lite. This receiver example can be used individually or in conjunction with the transmitter example.
If used stand-alone, another CAN node must be present on the CAN bus with the same timing and with
the same messaging characteristics.  This example is available for hardware testing of the CAN and
is provided to be used as reference code for setting up the CAN to do simple receive operations.
More robust examples will be provided in a future tools update.

Files contained in this directory:

readme.txt				This project description file
CAN_RX.dpj			VisualDSP++ project file
main.c				C file containing the main program 
Initialization.c	C file containing all initialization routines
Interrupts.c		C file containing the interrupt service routines for CAN TX, CAN RX, and PORT F
CAN_Functions.c		C file containing CAN-specific Functions
CAN_RX.h			Header file containing prototypes, global data, and macros
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CONTENTS

I.	FUNCTIONAL DESCRIPTION
II.	IMPLEMENTATION DESCRIPTION
III.OPERATION DESCRIPTION

I.    FUNCTIONAL DESCRIPTION

This example demonstrates the initialization of the Port pins, Interrupts, and the CAN interface.

Theis program initializes the CAN the same way the TX program does.  In addition to setting up
the CAN and the Port, this program executes a blink routine that scrolls a light across the
LEDs from left to right.  Upon receipt of a byte into Mailbox 7, the CAN RX ISR checks for a
valid command of 0x01, 0x02, 0x03, or 0x04, and sets a series of software flags that are used by
the CAN RX main routine to determine what is displayed on the LEDs.  Valid commands change the
display to blink all 6 LEDs (0x01), scroll the LED left-to-right (0x02) or right-to-left (0x03),
or turn all of the LEDs off (0x04).  An unrecognized command will turn the LEDs off.  After the
command is received, this program writes the value of the command into mailbox 24 and sends
it back out the CAN controller.

II.   IMPLEMENTATION DESCRIPTION

The main file calls the following sub-routines:

1.	Init_PLL()
2.	Init_Port()
3.	Init_Interrupts()
4.	Init_CAN_Timing()
5.	Init_CAN_Mailboxes()
6.	CAN_Setup_Interrupts()
7.	CAN_Enable()

It then executes an endless blink routine and takes CAN interrupts to change the pattern.

III.  OPERATION DESCRIPTION

- Make sure that switch SW2.4 is turned on (Attaches PJ4 to CAN_RX Pin)
- Open project "CAN_RX.dpj" in VisualDSP++ Integrated Development Environment (IDDE).
- Under the "Project" tab, select "Build Project" (program is then loaded automatically into DSP).
- Select "Run" from the "Debug" tab on the menu bar of VisualDSP++.
- Observe scrolling LED on board after initialization is completed.

- If two EZ-KITs are used, the transmitter will display the command sent via push-button interrupt
  on the LEDs when the response comes back from the receiver board.