Texas Instruments Incorporated

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GC1012B 3.3V DIGITAL TUNER

SLWS138B

This document contains information which may be changed at any time without notice

1.2

BLOCK DIAGRAM

A block diagram illustrating the major functions of the chip is shown in Figure 1

Figure 1. GC1012B Block Diagram

Each of these functions are described below.

1.3

CONTROL INTERFACE

The control interface performs four major functions: It allows an external processor to configure the

chip, it allows an external processor to capture and read output samples from the chip, it allows an external

processor to perform diagnostics, and it generates internal synchronization strobes.

The chip is configured by writing control information into 8 bit control registers within the chip. The

contents of these control registers and how to use them are described in Section 3. The registers are written

to or read from using the C[0:7], A[0:3], WE, RE, and CE pins. Each control register has been assigned a

unique address within the chip. An external processor (a microprocessor, computer, or DSP chip) can write

into a register by setting A[0:3] to the desired register address, setting the CE pin low, setting C[0:7] to the

desired value and then pulsing WE low. RE must remain high

To read from a control register the processor must set A[0:3] to the desired address, set CE low,

and then set RE low. The chip will then drive C[0:7] with the contents of the selected register. After the

processor has read the value from C[0:7] it should set RE and CE high. The C[0:7] pins are turned off (high

impedance) whenever CE is high or WE is low.

DIAG-

NOSTIC

RAMP

DIGITAL

OSCILLATOR

COS

SIN

DIAG

SELECT

FREQ

PROGRAMMABLE

LOW PASS

FILTER

GAIN

ADJUST

OUTPUT

FORMAT

CHECKSUM

GAIN

I/Q

BANDWIDTH

CONTROL INTERFACE

C0-C7

A0-A3

CE

WE

REAL,

CHECKSUM

I

Q

(10,12,14, OR 16 BITS)

STROBES

(WS,IFLAG)

SYNCS OUT

(SO,OS,INT,OFLOW)

CK

YNCS IN

S,AS,GS)

X

VCC

GND

AND

SAMPLES

OUTPUTS

OPTIONS

FLIP

OFFSET

(12 BITS)

RE

(CS)

(R/W)

(GND)

(<- GC1012A Signal Names)