AN2573 Freescale Semiconductor / Motorola, AN2573 Datasheet - Page 4

• Manufacturer Part Number: AN2573
• Description: LINkits LIN Evaluation Boards
• Manufacturer: Freescale Semiconductor / Motorola

AN2573/D
4
V
Bat
GND
LIN
2.2 k
10 k
6
3
~12 V
LIN
WAKE
7
V
Sup
MC33399
GND
8
5
5
8
INH
devices, the pin-outs of P1 and P2 are as consistent as possible across all the
boards. The masters have additional pins available on a third 20-way
connector, P3.
The basic circuit diagram of a LIN slave node is very simple. It comprises the
MCU, the LIN physical interface, and a 5-volt regulator. In this case, the
physical interface used is the MC33399 and the regulator is an LT1121, though
these two chips could be replaced by a single chip, the MC33689 LIN SBC
(systems base chip). The MCU enables the MC33399, which controls the
regulator. When there is no LIN activity, the MC33399 shuts down the
regulator, thus powering down the MCU and putting the node to sleep with an
I
demonstration software is written in such a way that at least one LED is always
on when the MCU is powered up. An absence of LIN bus activity will not cause
the MC68HC908QY4 to go to sleep.
1. To achieve this current, the LED attached to the 12-V line should be removed from the board.
LT1121
DD
27 k
(MONITOR
3
Freescale Semiconductor, Inc.
EN
Rx
Tx
of less than 50
Figure 1. MC68HC908EY16 LINkits Slave
MODE)
For More Information On This Product,
J2
47 k
2
1
4
OSCILLATOR MODULE
1
(DEBUG)
J3
5 V (DEBUG)
LINkits LIN Evaluation Boards
1 k
Go to: www.freescale.com
9.1 V
ZENER
1
J4
. This can be seen by the LEDs switching off because the
100 k
17
24
23
9
6
5 V
B5
IRQ
E1
E0
OSC1
(ESCI)
V
V
V
28
29
30
DD
DDA
REFH
MC68HC908EY16
27
26
25
47 k
V
V
V
SS
SSA
REFL
RESET
13
100 nF
A4
B0
B1
B2
B3
31
18
14
12
11
1 k
1 k
RESET
100 k
1 k
1 k
S1
PUSH-BUTTON
MOTOROLA