atmega32c1 ATMEL Corporation, atmega32c1 Datasheet - Page 204

• Manufacturer Part Number: atmega32c1
• Description: Atmega32m1 Automotive 8-bit Avr Microcontroller With 32k/64k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

17.3.3
17.3.4
17.3.5
17.4
17.4.1
204
LIN / UART Controller
ATmega32/64/M1/C1
Data Transport
Schedule Table
Compatibility with LIN 1.3
LIN Overview
Two types of data may be transported in a frame; signals or diagnostic messages.
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The master task (in the master node) transmits frame headers based on a schedule table. The
schedule table specifies the identifiers for each header and the interval between the start of a
frame and the start of the following frame. The master application may use different schedule
tables and select among them.
LIN 2.1 is a super-set of LIN 1.3.
A LIN 2.1 master node can handle clusters consisting of both LIN 1.3 slaves and/or LIN 2.1
slaves. The master will then avoid requesting the new LIN 2.1 features from a LIN 1.3 slave:
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LIN 2.1 slave nodes can not operate with a LIN 1.3 master node (e.g. the LIN1.3 master does
not support the enhanced checksum).
The LIN 2.1 physical layer is backwards compatible with the LIN1.3 physical layer. But not the
other way around. The LIN 2.1 physical layer sets greater requirements, i.e. a master node
using the LIN 2.1 physical layer can operate in a LIN 1.3 cluster.
The LIN/UART controller is divided in three main functions:
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These functions mainly use two services:
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Because these two services are basically UART services, the controller is also able to switch
into an UART function.
The LIN/UART controller is designed to match as closely as possible to the LIN software appli-
cation structure. The LIN software application is developed as independent tasks, several slave
tasks and one master task (c.f.
Signals
Signals are scalar values or byte arrays that are packed into the data field of a frame. A sig-
nal is always present at the same position in the data field for all frames with the same iden-
tifier.
Diagnostic messages
Diagnostic messages are transported in frames with two reserved identifiers. The interpreta-
tion of the data field depends on the data field itself as well as the state of the communicat-
ing nodes.
Enhanced checksum,
Re-configuration and diagnostics,
Automatic baud rate detection,
"Response error" status monitoring.
Tx LIN Header function,
Rx LIN Header function,
LIN Response function.
Rx service,
Tx service.
Section 17.3.4 on page
204). The ATmega32/64/M1/C1 con-
7647A–AVR–02/08