HT85F2270 datasheet(160/226 Pages) HOLTEK

160 / 226 page

Rev. 1.00

160 of ��6

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Standard 8051 8-Bit Flash MCU

HT85F2260/HT85F2270/HT85F2280

Temperature Sensor

A temperature sensor circuit is provided to measure the temperature which the designer can use

to adjust some measured parameters. The temperature sensor output voltage is proportional to the

temperature increment and can be amplified by the PGA. The accompanying diagram illustrates the

basic relationship between the measured temperature and the voltage output. However, the designer

should consider that the temperature sensor output voltage might be affected by the manufacturing

process.

The ADC temperature sensor input channel is selected by the ACS4 bit. The TSEN bit in the

ADCR1 register controls the temperature sensor enable/disable function. When the function is

disabled, the temperature sensor defaults to an unknown state and any A/D conversion performed

on the sensor will generate undefined data.

A/D Reference Voltage Source

The A/D can obtain its reference voltage from three different sources, the VCCA3 power supply

pin, an externally supplied reference voltage supplied on pin VREF or from the internal voltage

reference generator. Two bits control which reference source is selected, these are the VREFIS and

VREFAS bits.

A/D Converter Voltage Reference Select

VREFIS

VREFAS

Reference Source

VCCA� pin

Externall� supplied on VREF pin

VCCA� pin

Internal Voltage Reference Generator

HT85F2270 Datasheet(PDF) 160 Page - Holtek Semiconductor Inc