AN2633 Freescale Semiconductor / Motorola, AN2633 Datasheet - Page 5

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

Faster, More Efficient
Interrupt Servicing
MOTOROLA
Figure 2. SLIC versus UART-Based Interrupt Handling
With 10 fewer interrupts to service (an 83.3% reduction in interrupts), the CPU
is free for a much greater amount of time. Using the SLIC module instead of a
UART-based solution significantly reduces the chance of an interrupt
interfering with other application operations.
In addition to reducing the number of interrupts required to service a LIN frame
(two interrupts only), the SLIC module has been designed to maximize the
efficiency of the interrupt service routine (ISR), which minimizes the CPU
requirements for LIN communications. A patented encoding method is used to
allow the ISR to service all SLIC interrupts in a short, fixed, and predictable
amount of time. Details of this are explained in
Assembly Source Code Basic SLIC
Because the SLIC module automates standard LIN communication functions,
less time is spent inside the ISR. Checksum calculations have been
automated, which eliminates the extra instructions that would be needed to
perform this calculation in a UART solution. This further reduces the amount of
LIN Drivers for SLIC Module on the MC68HC908QL4
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
Driver.
SLIC Module Operation, Features, and Benefits
CodeWarrior Project —
AN2633/D
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