Atmel 7698AAUTO01/07, Руководство пользователя

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Using the ATAVRAUTO200
ATAVRAUTO200 User Guide 2-5
7698A–AUTO–01/07
Table 2-1. LIN ressources
Figure 2-3. LIN transceiver and power supply
Note: The LIN transceiver undervoltage protection can be disabled by removing the
NISP jumper.
Note: The NISP jumper has to be removed when programming.
2.4.2 Power supply measurement
The voltage measurement is realized with a bridge of resistors. The read value is 0.281
of the LIN power supply (47 K
Ω / (47 K Ω + 120 K Ω )). Input voltage on channel 1 of the
ADC is limited to 5.1V by a zener diode. This will give a voltage reading range from 0 to
18.1V with Vcc as reference.
The power supply measurement can be performed using the A/D converter. See the
ATmega48/88/168 datasheet for how to use the ADC. The input voltage value (V
IN
) is
calculated with the following expression:
Where:
V IN
= Input voltage value (V)
V ADC7
= Voltage value on ADC-1 input (V)
Function Port State Description
LIN_NSLP PD2 Low LIN transceiver in Sleep mode
High LIN transceiver in normal mode
NRES_LIN PC6 Low Perform MCU reset when NISP Jumper is inserted
High No Action
+
V
B
a
t
G
N
D
L
IN
V
IN
3.55
V
A DC
1
×
=