TCM4400EPET datasheet(44/64 Pages) TI

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TCM4400E

GSM/DCS BASEBAND AND VOICE A/D

AND D/A RF INTERFACE CIRCUIT

SLWS082A – JULY 1999 – REVISED MARCH 2000

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

BDLON

BCAL

BULON

BENA

DLON

DLCAL DLREC

ULON

ULCAL ULSEND

CKDL

CKUL

Figure 17. Timing Interface

DSP/MCU serial interface operation and format

The DSP/MCU serial interface configures the GSM baseband, the voice A/D and D/A converters (read and write

operation in internal registers), and transmits RF data to the DSP during the reception of a burst by the downlink

path of the GSM baseband and voice A/D and D/A circuitry.

During reception of a burst (bit DLR of the status register is 1) and DSP serial interface and associated internal

bus are dedicated to the transfer of RF data from the GSM baseband A/D and D/A converters to the DSP. During

this period only a write operation of internal registers can be done through the DSP serial interface. However,

all registers can be accessed by the serial MCU interface.

During transmission of a burst (bit ULX of the status register is 1) no read or write operation can be done in the

registers of the baseband uplink part of the GSM baseband, APC RAM, and APC shape register.

Writing or reading registers using the serial interface is done by transferring 16-bit words to the serial interface.

Each word is split into three fields as shown in Table 4.

Table 4. Read/Write Data Word

DATA

ADDRESS

R/W

1 / 0

When writing to internal registers observe the following convention:

Bit 0

: A 0 indicates a write operation.

Bits 1 to 5

: This field contains the address of the register to be accessed.

Bits 6 to 15

: This field contains the data to be written into the internal register.

When reading from internal registers observe the following convention:

Bit 0

: A 1 indicates a read operation.

Bits 1 to 5

: This field contains the address of the register to be accessed.

Bits 6 to 15

: This field is an irrelevant status in a read request operation.

TCM4400EPET Datasheet(PDF) 44 Page - Texas Instruments

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