AN2503 Freescale Semiconductor / Motorola, AN2503 Datasheet - Page 3

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

Error Detection
LIN Driver Software
Description
MOTOROLA
The slave must detect these errors:
Fault confinement depends on system requirements and is not part of the LIN
specification. The most common procedure for fault confinement is performed
by the master asking for the slave status flags.
Because this LIN driver will be implemented in a very small MCU, there are
several aspects that should be considered when implementing the driver:
Slave LIN Driver for the MC68HC908QT/QY Family
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Freescale Semiconductor, Inc.
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Bit error — When sending data, the data monitored on the bus is
different from the bit value that is sent
Checksum error — When receiving data, the sum of the inverted
modulo-256 of received bytes plus the checksum is not 0xFF
Identifier parity error — When receiving data, the expected ID parity bits
are not equal to the received ones
Small size — Size is dependent on the needs of the application and can
be less than 650 bytes with minimum functionality or less than 1 K and
support the LIN specification.
High modularity — Based on the application needs, modules can be
configured to enable or disable LIN functionality such as sleep mode, bit
error checking, and parity checking. As modules are disabled, the code
is reduced without affecting functionality.
Flexibility — This driver supports sleep mode specification 1.3 and
earlier versions. It can also be configured to manage IDs in different
ways, so that the user can choose the best option for the application.
Easy hardware changes — All I/O pins used can be configured easily to
change according to the application needs.
Minimal hardware required — Only one timer channel is used, allowing
the user to use the second one; however, the timer is shared and the
channels can’t be managed simultaneously. If a transceiver isn’t used,
only one pin can be used for input and output (from the timer). If the
transceiver is used, only two general-purpose I/O pins and the one used
by the timer can be used. If sleep mode is enabled, IRQ can be used as
an input, or a regulator will handle this functionality.
Go to: www.freescale.com
LIN Basic Concepts
AN2503/D
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