DA6512.000

11 July, 2012

6 (26)

OPERATING MODES

MAS6512

has

two

capacitance

measurement

modes and one temperature measurement mode.

In capacitance measurement mode the output is

measurement mode the output is proportional to the

absolute temperature.

Measurement mode configuration and start of

conversion is done by writing 8-bit configuration

data to the Measurement control register (address

control register chapter.

MAS6512 includes a 256-bit EEPROM memory for

storing trim and calibration data on chip. Four bytes

(32 bits) of EEPROM are reserved for trim values

but the remaining 28 bytes (224 bits) are free for

calibration and other data.

The stored trim data consists of measurement

configuration settings that are automatically read

from EEPROM memory in the beginning of each

conversion.

The calibration data should comprise of calibration

and temperature compensation coefficients that can

be used to calculate accurate calibrated sensor and

temperature measurement results from the non-

calibrated measurement reading. All calculations

need to be done in an external micro controller unit

(MCU).

A calibrated MAS6512 sensor system should be

operated as illustrated in figure 2. The calibration

and compensation coefficients need to be read to

the MCU memory only once. From each pair of

sensor and temperature measurement readings the

accurate sensor and temperature values can then

be calculated by using an external MCU.

All communication with MAS6512 is done using

either the I

conversion, reading the conversion result and

reading and writing data from and to the EEPROM

memory are all accomplished via serial bus

communication.

In addition to the serial buses the digital interface

includes also end-of-conversion (EOC) and master

reset (XCLR) pins. See A/D Conversion in the Serial

Data Interface (I

Figure 2.

Flow chart for a calibrated MAS6512 sensor system

START

READ EEPROM

CALIBRATION DATA

MEASURE SENSOR

MEASURE TEMPERATURE

CALCULATE CALIBRATED

TEMPERATURE

CALCULATE TEMPERATURE

COMPENSATED SENSOR VALUE