LM98714 datasheet(63/115 Pages) TI1

63 / 115 page

LM98714

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SNAS254A – OCTOBER 2006 – REVISED JANUARY 2014

Serial Interface

A serial interface is used to write and read the configuration registers. The interface is a three wire interface

using SCLK, SEN, and SDIO connections. The main input clock (INCLK) to the LM98714 must be active during

all Serial Interface commands.

WRITING TO THE SERIAL REGISTERS

To write to the serial registers, the timing diagram shown in Figure 61 must be met. First, SEN is toggled low.

The LM98714 assumes control of the SDIO pin during the first eight clocks of the command. During this period,

data is clocked out of the device at the rising edge of SCLK. The eight bit value clocked out is the contents of the

previously addressed register, regardless if the previous command was a read or a write. At the rising edge of

ninth clock, the LM98714 releases control of the SDIO pin. At the falling edge of the ninth clock period, the

master should assume control of the SDIO pin and begin issuing the new command. SDIO is clocked into the

LM98714 at the rising edge of SCLK. The remaining bits are composed of the “write” command bit (a zero), two

device address bits (zeros for the LM98714), five bit register address to be written, and the eight bit register

value to be written. When SEN toggles high, the register is written to, and the LM98714 now functions with this

new data.

Figure 61. Serial Write

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LM98714 Datasheet(PDF) 63 Page - Texas Instruments