AN2633 Freescale Semiconductor / Motorola, AN2633 Datasheet - Page 8

• Manufacturer Part Number: AN2633
• Description: LIN Drivers for SLIC Module on the MC68HC908QL4
• Manufacturer: Freescale Semiconductor / Motorola

AN2633/D
Hardware — M68EVB908QL4 Evaluation Board
8
The QL4 evaluation board is made from a QL4 with an added enhanced LIN
interface, which consists of an MC33661 enhanced LIN transceiver and a 5-V
regulator (an LT1121 chip). The board can be programmed either using the
RS-232 MON08 interface or a Cyclone/MultiLink tool.
The primary difference between the EVB and the LIN kit board is the
connection of inputs and outputs. There is only one LED (D1) on the EVB,
which is used for displaying the least significant data bit. This bit is inverted in
software to accommodate the circuitry differences in the boards, keeping the
interface consistent so that a logic 1 turns on the LED.
The other three bits of data, which are output to LEDs D7, D6, and D5 on the
LIN kit board, are still brought out to PTB1, PTB2, and PTB6, respectively.
The input button is used differently on the LIN kit board and EVB. Because
there is not a dedicated button for the application on the EVB, the reset button
is reused. Because the reset function on the QL4 device isn’t active unless
activated by software in user mode, there is no problem using this button for the
application.
Another major difference with running application code on the EVB is the
presence of the enhanced LIN transceiver (MC33661). This allows the
possibility of controlling the physical layer slew rate through software control of
the enable (EN) pin of the device. Operation of this feature is beyond the scope
of this application note. Refer to the documentation for the MC33661 device for
more information.
LIN Drivers for SLIC Module on the MC68HC908QL4
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
MOTOROLA