SN65512B, SN75512B

VACUUM FLUORESCENT DISPLAY DRIVERS

SLDS016A − DECEMBER 1985 − REVISED OCTOBER 1989

4−4

POST OFFICE BOX 655303

POST OFFICE BOX 1443

logic diagram (positive logic)

1D

C1

C2

2D

DATA IN

CLOCK

1D

C1

C2

2D

1D

C1

C2

2D

1D

C1

C2

2D

R11

R12

R2

R1

LC12

LC11

LC2

LC1

Q1

Q2

Q11

Q12

Latches

Shift

Register

SERIAL OUT

STROBE

LATCH

ENABLE

8 Stages

(Q3 thru Q10)

Not Shown

FUNCTION TABLE

CONTROL INPUTS

SHIFT REGISTER

LATCHES

OUTPUTS

FUNCTION

CLOCK

LATCH

ENABLE

STROBE

SHIFT REGISTER

R1 THRU R12

LATCHES

LC1 THRU LC12

SERIAL

Q1 THRU Q12

Load

↑

X

X

Load and shift†

Determined by LATCH

‡

R12

Determined by STROBE

Load

↑

No

↑

XX

Load and shift†

No change

Determined by LATCH

ENABLE‡

R12

Determined by STROBE

Latch

X

L

X

As determined above

Stored data

R12

Determined by STROBE

Latch

X

L

H

X

As determined above

Stored data

New data

R12

Determined by STROBE

Strobe

X

X

H

As determined above

Determined by LATCH

‡

R12

All LC

Strobe

X

X

H

L

As determined above

Determined by LATCH

ENABLE‡

R12

All LC

LC1 thru LC12, respectively

H = high level, L = low level, X = irrelevant,

↑ = low-to-high-level transition

† R12 takes on the state of R11, R11 takes on the state of R10, . . . R2 takes on the state of R1, and R1 takes on the state of the data input.

‡ New data enter the latches while LATCH ENABLE is high. These data are stored while LATCH ENABLE is low.