Using the ATAVRAUTO200
2-4
ATAVRAUTO200 User Guide
7698A–AUTO–01/07
2.2
Power Supply
The on-board power supply circuitry is supplied through the LIN connector.
2.2.1
LIN powered
The LIN connector power line is used to provide VBAT to the ATAVRAUTO200 LIN
transceiver.
A LIN network has to be connected to have your LIN interface function (Input supply
from 8 up to 18V DC, see Figure 2-3 on page 5) .
2.3
Oscillator Sources
The ATAVRAUTO200 board allows only one oscillator source:
Internal RC oscillator (Default configuration).
Note:
The “Divide by 8” Fuse is configured by default. The first step in the demonstra-
tion application is to clear the prescaler to have the internal RC oscillator run-
ning at 8MHz:
CLKPR = (1<<CLKPCE); //! Clear Prescaler
CLKPR = 0;
2.3.1
Interal RC oscillatorn
A LIN Slave node with a run-time oscillator calibration can be used with the internal RC
oscillator.
At ambiant temperature and normal Vcc, the internal oscillator is precise enough to be
compliant with LIN 1.3 and 2.0 specifications. For wider temperature and/or power
ranges, a run-time calibration of the internal RC oscillator can be used as explained in
the application note AVR140: “ATMega48/88/168 family run-time calibration of the inter-
nal RC oscillator” available on the Atmel website.
2.4
On-board Resources
2.4.1
LIN & Power supply
The LIN screwed connector allows the user to select his own connector.
Note:
The LIN power supply input is reverse voltage protected.
LIN transceiver control is realized by the micrcontroller. All modes depend on microcon-
troller’s ports configuration.
