MC44BC373C/374C Technical Data

Modulator Description

13.5 Test Bit TB1

This test bit allows a different bus format.

•

TB1=0 — All MC44BC373C/4C Functions Available—Normal Mode.

•

TB1=1 — Limited Software Compatibility with MC443533. MC44BC373C/4C Functions Not

Available. TB1=1, allows a first evaluation of MC44BC373C/4C using software developed for

MC44353 devices.

13.6 Transient Output Inhibit

To minimize the risk of interference to other channels while the UHF PLL is acquiring a lock on the

desired frequency, the Sound and Video modulators are turned OFF during a time out period for each of

the following two cases:

•

Power-ON from zero (i.e., all Vcc is switched from 0 V to 5V ).

•

UHF oscillator power-ON from OFF state (i.e., OSC bit is switched from 1 to 0)

There is a time-out of 263ms until the output is enabled. This lets the UHF PLL settle to its programmed

frequency. During the 263ms time-out, the sound PLL current source is set to 10

µA typical to speed up the

locking time. After the 263ms time-out, the current source is switched to 1

µA. Use care when selecting

loop filter components, to ensure the loop transient does not exceed this delay.

For test purposes, it is possible to disable the 263ms delay using Test Mode1–State1.h (this is called speed

up mode).

13.7 UHF Oscillator—VHF range

The UHF oscillator is fully integrated and does not require any external components.

For low frequency testing or VHF range operation (test mode 1, states 1.b to 1.c), the UHF oscillator can

be internally divided by: 2, 4, 8, or 16.

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ACK

CA—CHIP ADDRESS

11001010

ACK

C1—High Order Bits

1

*

*

*

PS

*

*

SYSL

ACK

C0—Low Order Bits

*

*

*

SFD1

SFD0

1

0

0

ACK

FM—High Order Bits

0

TPEN

N11

N10

N9

N8

N7

N6

ACK

FL—Low Order Bits

N5

N4

N3

N2

N1

N0

*

*

ACK

† Case TB1=1 compatible with MC44353

•

All “

∗” are don’tcare bits.

•

PS bit replaces PSD2 bit in MC44353 bus format:

•

PS = 0 is for Picture-to-Sound ratio = 12dB

•

PS = 1 is for Picture-to-Sound ratio = 16dB

•

SFD1 and SFD0 bits have the same definition for both bus formats (MC44353 and MC44BC373C/4C) and

allows a select sound frequency between 4.5MHz, 5MHz, 5.5MHz, and 6.5MHz.

•

SYSL bit is the same definition for both bus formats (MC44353 and MC44BC373C/4C) and allows a select

system L or BG.

•

All MC44BC373C/4C functions are set to their default values.

Freescale Semiconductor, Inc.

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