SERIAL PORT OPERATION

The serial port interface is a bi-directional port for reading and writing programming data from/to the in-

ternal registers of this device. For data transfers SDEN* is brought high, serial data is presented at the

SDATA pin, and a serial clock is applied to the SCLK pin. After the SDEN* goes high , the first 16 pulses

applied to the SCLK pin will shift the data presented at the SDATA pin into an internal shift register on

the rising edge of each clock. An internal counter prevents more than 16 bits from being shifted into the

register. The data in the shift register is latched after the 16th SCLK pulse. If less than 16 clock pulses

are provided before SDEN* goes low, the data transfer is aborted.

All transfers are shifted into the serial port LSB first. The first byte of the transfer is for R/W and address

and instruction information. The first bit is R/W instruction bit, 0 is for WRITE and 1 is for READ.

Following 7 bits are Address.

INSTRUCTION, 1 BIT

ADDRESS, 7 BITS

D98IN845

DATA, 8 BITS

SDEN

SCLK

SDATA

Figure 2. Serial Port Data Transfer Format.

INTERNAL REGISTER DEFINITION

Reg:

Name:

Type:

Address:

0

VCM DAC (High) Register

Write only

0Eh

BIT

LABEL

DESCRIPTION

0

VDAC BIT8

VCM DAC bit 8

1

VDAC BIT9

VCM DAC bit 9

2

VDAC BIT10

VCM DAC bit 10

3

VDAC BIT11

VCM DAC bit 11

4

VDAC BIT12

VCM DAC bit 12

5

VDAC BIT13

MSB resistor ladder of the 14 bit VCM DAC

6

PSM/LINEAR

Selects Voice Coil PSM or Linear Output Current Control. 1=PSM

0=Linear.

7

VCM_CAL

VCM calibration. 1 = Enables VCM control circuits and tristates

VCM power transistors.

L6268

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