AN2503 Freescale Semiconductor / Motorola, AN2503 Datasheet - Page 6

• Manufacturer Part Number: AN2503
• Description: Slave LIN Driver for the MC68HC908QT/QY Family
• Manufacturer: Freescale Semiconductor / Motorola

AN2503/D
Driver Functionality
6
The following is a description of the LIN implementation in an MC68HC908QY
MCU. Some functionality may be more understandable if the MCU is familiar.
More information on this MCU and its pinout can be found in the
MC68HC908QY4 Signal
Because this microcontroller doesn’t have an SCI module, one channel from
the timer will be used as an input and a general-purpose pin will be used as an
output using the timer overflow functionality. To lower the costs, the internal
oscillator can be used through the synch frame feature.
The flow diagram of the driver can be seen in
1. Initialize all variables.
2. Driver will perform all the functionality in the Interrupt service routines. In
3. After a valid break is detected, all the following fields will be expected:
Slave LIN Driver for the MC68HC908QT/QY Family
Freescale Semiconductor, Inc.
For More Information On This Product,
the idle state, it will wait for a new frame.
a.
b.
c.
•
•
Synch field (where trimming process may occur)
Identifier field (where the slave task will be defined)
Proper action will be executed (either reception or transmission)
Go to: www.freescale.com
Reception — Waits for the data fields to be defined, store
definitions in the proper buffer and calculate checksum field.
Transmission — Sends the corresponding buffer and its
checksum. If a sleep mode frame is detected, the MCU will either
enter low power-consumption mode, or it will power off if a
regulator is used.
Description.
Figure
3.
MOTOROLA