MC33794 Просмотр технического описания (PDF) - Motorola => Freescale

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MC33794

Electric Field Imaging Device

Motorola => Freescale 

RST

1

WD_IN

2

NC

3

LAMP_GND

4

NC

5

LAMP_CTRL

6

NC

7

LAMP_SENSE

8

LAMP_MON

9

DIS_SHIELD

10

D

11

C

12

B

13

A

14

SIGNAL

15

LEVEL

16

PWR_MON

17

LP_CAP

18

R_OSC

19

NC

20

NC

21

NC

22

NC

23

CLK

24

VDD_MON

25

VDD

26

VPWR

27

54

LAMP_OUT

53

ISO-9414

52

NC

51

ISO_IN

50

NC

49

NC

48

NC

47

ISO_OUT

46

REF_B

45

REF_A

44

E9

43

E8

42

E7

41

E6

40

E5

39

E4

38

E3

37

E2

36

E1

35

TEST

34

NC

33

NC

32

GND

31

NC

30

SHIELD

29

AGND

28

VCC

SOICW-EP PIN FUNCTION DESCRIPTION

Pin

Pin Name

Formal Name

1

RST

Reset

2

WD_IN

Watchdog In

3, 5, 7,

20–23, 31,

33, 34,

48–50, 52

4

NC

LAMP_GND

6

LAMP_CTRL

8

LAMP_SENSE

9

LAMP_MON

No connect

Lamp Ground

Lamp Control

Lamp Sense

Lamp Monitor

Definition

This output is intended to generate the reset function of a typical MCU. It has a delay

for power-on reset, level detectors to force a reset when VCC is out-of-range high or

low, and a watchdog timer that will force a reset if WD_IN is not asserted at regular

intervals. Timing is derived from the oscillator and will change with changes in the

resistor attached to R_OSC.

This pin must be asserted and deasserted at regular interval in order to prevent RST

from being asserted. By having the MCU program perform this operation more often

the allowed time, a check that the MCU is running and executing its program is

assured. If this doesn’t occur, the MCU will be reset. If the watchdog function is not

desired, this pin may be connected to CLK to prevent a reset from being issued.

These pins may be used at some future date and should be left open.

This is the ground for the current from the lamp. The current into LAMP_OUT flows

out through this pin.

This signal is used to control the lamp driver. A high logic level turns on the lamp.

This pin is normally connected to the LAMP_OUT pin. The voltage at this pin is

reduced and sent to LAMP_MON so the voltage at the lamp pin is brought into the

range of the analog-to-digital converter (ADC) in the MCU.

This pin is connected through a voltage divider to the LAMP_SENSE pin. The

voltage divider scales the voltage at this pin so that battery voltage present when the

lamp is off is scaled to the range of the MCU ADC. With the lamp off, this pin will be

very close to battery voltage if the lamp is not burned out and the pin is not shorted

to ground. This is useful as a lamp check.

33794

6

MOTOROLA ANALOG INTEGRATED CIRCUIT DEVICE DATA

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