The levels on these three terminals determine which of the five antiblooming modes is selected:

Mode

ABS2

ABS1

ABS0

Operation

0

NC

L

L

No ABG pulses

1

NC

H

L

2-MHz burst of ABG pulses

2

NC

L

H

1-MHz burst of ABG pulses

3

H

H

H

1-MHz continuous ABG pulses

4

L

H

H

2-MHz continuous ABG pulses

SN28837

1/2-INCH PAL TIMER

SOCS031B – JULY 1991

3

POST OFFICE BOX 655303

Terminal Functions

TERMINAL

I/O

DESCRIPTION

NAME

NO.

I/O

DESCRIPTION

ABIN

38

O

Antiblooming in

ABS0

21

I

ABS1

22

I

ABS2

23

I

Mode 1 is used for normal operation.

BCP1

1

O

Optical black clamp

BCP2

2

O

Optical black clamp

BF

7

O

Burst flag

CBLK

6

O

Composite blank

CLK

50

O

3.34-MHz clock (factory-test point)

CLK13M

47

O

13-MHz clock (connect to SN28838 color-subcarrier generator for color operation)

CP1

3

O

Clamp 1 (signal processing)

CP2

4

O

Clamp 2 (signal processing)

CSYNC

5

O

Composite sync

E/L

19

I

Delay select for S1, S2, S3. When E/L is high, the three serial-transfer pulses occur early relative to the

sample-and-hold pulses SH1, SH2, and SH3. When E/L is low, the three serial-transfer pulses occur late

relative to the sample-and-hold pulses.

FI

13

O

Field index

GND

41, 60

Ground

GP

27

I

Exposure control: GP gates the PS and PI outputs (see the description of GPS)

GPS

26

I

When GPS is high, the timer operates in the normal-integration-time mode (tint = 20 ms) and VD is

connected internally to GP. To operate the imager in the variable-integration-time mode, GPS must be

held low and a user-defined logic circuit must be inserted between VD and GP to vary the integration time

(see Figure 1).

GT

37

O

TMS3473B parallel-driver MIDSEL input switch

GT1/SH3

56

O

GT1/SH3 is a logic signal for both Y gate 1 of the TL1051 video preprocessor and sample-and-hold

channel 3 of the TL1593 3-channel sample-and-hold circuit.

GT2

57

O

Y gate 2 for the TL1051 video preprocessor

GT3/SH2

53

O

GT3/SH2 is a logic signal for both Y gate 3 of the TL1051 video preprocessor and sample-and-hold

channel 2 of the TL1593 3-channel sample-and-hold circuit.

HCR

59

I

Horizontal-counter reset

HGATE

11

O

Decoded H count signal. HGATE is a test point and is not used in normal operation.

HIGH

25

I

Not used (tie high)

IDP

10

O

ID pulse (for SECAM operation)

LSW

48

O

Line switch (connect to SN28838 for color operation)

NC

15, 30,

35, 46,

52, 54, 55

No connect

PD

49

O

Power down. A low-logic level on PD causes the device to enter a low power-consumption mode.

PI

39

O

Parallel-image-area gate clock

PS

36

O

Parallel-storage-area gate clock

SB

29

I

Standby-mode select. When SB is high, normal operation is selected; when SB is low, the power-down

mode is selected.

SCBLK

9

O

Subcarrier blank (for SECAM applications)