Datasheet

START (S)

STOP (P)

SDA

SCL

SDA

SCL

SDA

SCL

Data line stable;

Data valid

Change

of data

allowed

bq24190, bq24192

bq24192I, bq24193

SLUSAW5A –JANUARY 2012–REVISED OCTOBER 2012

www.ti.com

Serial Interface

The bq24190, bq24192, bq24192I, bq24193 uses I

C compatible interface for flexible charging parameter

programming and instantaneous device status reporting. I2C

is a bi-directional 2-wire serial interface

developed by Philips Semiconductor (now NXP Semiconductors). Only two bus lines are required: a serial data

line (SDA) and a serial clock line (SCL). Devices can be considered as masters or slaves when performing data

transfers. A master is the device which initiates a data transfer on the bus and generates the clock signals to

permit that transfer. At that time, any device addressed is considered a slave.

The device operates as a slave device with address 6BH, receiving control inputs from the master device like

micro controller or a digital signal processor. The I

C interface supports both standard mode (up to 100kbits), and

fast mode (up to 400kbits).

Both SDA and SCL are bi-directional lines, connecting to the positive supply voltage via a current source or pull-

up resistor. When the bus is free, both lines are HIGH. The SDA and SCL pins are open drain.

Data Validity

The data on the SDA line must be stable during the HIGH period of the clock. The HIGH or LOW state of the

data line can only change when the clock signal on the SCL line is LOW. One clock pulse is generated for each

data bit transferred.

Figure 33. Bit Transfer on the I

C Bus

START and STOP Conditions

All transactions begin with a START (S) and can be terminated by a STOP (P). A HIGH to LOW transition on the

SDA line while SCl is HIGH defines a START condition. A LOW to HIGH transition on the SDA line when the

SCL is HIGH defines a STOP condition.

START and STOP conditions are always generated by the master. The bus is considered busy after the START

condition, and free after the STOP condition.

Figure 34. START and STOP conditions

Product Folder Links: bq24190 bq24192 bq24192I bq24193