Gpadc(General Purpose Adc) And Autoadc2 - LG TU750 Service Manual

3. TECHNICAL BRIEF

3.4 GPADC(General Purpose ADC) and AUTOADC2

The General Purpose Analog–to-Digital Converter (GPADC) consists of a 14 input
Multiplexer (MUX) and a 10-bit ADC. The analog input signal is selected with the MUX
and converted in the ADC. The digital output data is stored in registers in the I²C block,
some of them cleared after read-out, see the I²C Map
The voltages at CHSENSE-, DCIO, BDATA, and the current feed to CHSENSE- cannot
be measured directly by the GPADC. Instead, level shifters and measuring amplifiers
translate these inputs to a voltage proportional to the input, and within the range of the
GPADC.
Additionally, the die temperature can be measured.
The ADC can operate in different modes and the different functions are set through I2C.
All operations are started on the rising edge of the internal strobe signal ADSTR, which
can be copied to the ADC output pin ADOUT. This signal is generated by an I2C MUX
write, or by the AUTOADC controller running in the background.
The data is stored in result registers in the I2C block. There are four result registers used
in manual GPADC measurements. Which registers to use for storing the result depends
on how the measurement was started. A measurement started by a write to the MUXa
register ends up in the GPRa register (8 MSB bits) and GPRla register (2 LSB bits), and a
write to the MUXb register ends up in the GPRb/GPRlb registers, accordingly.
The ADC block can be configured to adjust the measurement cycle in accordance with
the status of TXON signal, charger or SLEEP mode.
LGE Internal Use Only
Fig 3-4-1. GPADC and AUTOADC Block diagram
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Only for training and service purposes